Kinetis Microcontrollers Knowledge Base

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Kinetis Microcontrollers Knowledge Base

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The FlexIO module was first introduced in the Freescale Kinetis KL43 family. It is capable of emulating various serial communication protocols including: UART, SPI and I2C. The FlexIO module is very flexible and you can configure it according to your communication needs. The main components of the FlexIO module are the shifters, timers, and pins. Data is loaded onto a shifter and a timer is assigned to generate the shifter clock and use a pin to output the data from the shifter. The KL43 FlexIO module has 4 32-bit shifters, 4 16-bit timers and 8 bidirectional I/O pins. Each shifter and timer has its own configuration registers. The most important registers that configure the whole FlexIO behavior are the SHIFTCFG, SHIFTCTL, TIMCFG, TIMCTL and TIMCMP registers. There are other registers that contain status flags, interrupt enabling bits and the buffers for the shifters. Shifters have a timer assigned to them to generate the shift clock and it can be configured to shift data in or out. When the shifter is configured to transmit mode, the data from the SHIFTBUF register will be loaded to the shifter and the shifter status flag will be set meaning that the shifter is ready to start the transmission. In receive mode, the shifter status flag is set when SHIFTBUF has been loaded with the data from the shifter, and the status flag is cleared when the SHITBUF register is read. The timers are highly configurable, they can use external or internal triggers to generate certain conditions to reset, enable and disable the timer. The triggers can be a timer output, shifter status flag, pin input or an external trigger input. They can be configured to enable in response to a trigger, pin or shifter condition. Each shifter or timer can be configured to use any FlexIO pin with either polarity. The pins can be used as an input or output. A pin configured as an input for a timer can be used to receive a clock and use it as the shifter clock that is assigned to this timer. Once everything is configured you need to read/write the shifter buffers and the shifter and timer status flags to start a transmission or to read the contents of the shifter buffer when receiving data. The following diagram gives a high-level overview of the configuration of FlexIO timers and shifters. Figure 1. FlexIO block diagram In the following example configuration, the FlexIO module will be configured as a transmitter. It will use one shifter, two timers, and three pins. The pins will be used for the outputs of the shifter and the two timers. One timer will be used as the shifter clock and the other timer will be used as a chip select to show when a transmission is being made. The FlexIO will be configured to have a baud rate of FlexIO clock/4 and will do an 8-bit transmission. Figure 2. Example transmission Timer 0 Timer Configuration 0 Register (FLEXIO_TIMCFG0) = 0x00002200 TIMOUT = 0    Timer output is logic one when enabled and is not affected by timer reset. TIMDEC = 0    Decrement counter on FlexIO clock, Shift clock equals Timer output. TIMRST = 0    Timer never reset. TIMDIS = 2    Timer disabled on Timer compare. TIMENA = 2    Timer enabled on Trigger high. TSTOP  = 0    Stop bit is disabled. TSTART = 0    Start bit disabled. Timer Control 0 Register (FLEXIO_TIMCTL0) = 0x01C30101 TRGSEL = 1    Trigger select. Shifter 0 status flag. TRGPOL = 1    Trigger active low. TRGSRC = 1    Internal trigger selected. PINCFG = 3    Timer pin output. PINSEL = 1    Timer pin 1 select. PINPOL = 0    Pin is active high. TIMOD   = 1    Dual 8-bit counters baud/bit mode. Timer Compare 0 Register (FLEXIO_TIMCMP0) = 0x00000F01 TIMCMP = 0x00000F01        Configure 8-bit transfer with a baud rate of FlexIO clock/4. Set TIMCMP[15:8] = (number of bits x 2) - 1. Set TIMCMP[7:0] = (baud rate divider / 2) - 1. In our case we want an 8-bit transfer so TIMCMP[15:8] = 0xF and a baud rate divider of 4 so TIMCMP[7:0] = 0x1. Timer 1 Timer Configuration 1 Register (FLEXIO_TIMCFG1) = 0x00001100 TIMOUT = 0    Timer output is logic one when enabled and is not affected by timer reset. TIMDEC = 0    Decrement counter on FlexIO clock, Shift clock equals Timer output. TIMRST = 0    Timer never reset. TIMDIS = 1    Timer disabled on Timer N-1 disable. TIMENA = 1    Timer enabled on Timer N-1 enable. TSTOP   = 0    Stop bit is disabled. TSTART = 0    Start bit disabled. Timer Control 1 Register (FLEXIO_TIMCTL1) = 0x00030283 TRGSEL = 0    Trigger select. Doesn’t matter because we won’t use a trigger. TRGPOL = 0    Trigger active high. TRGSRC = 0    External trigger selected. PINCFG = 3    Timer pin output. PINSEL = 2    Timer pin 2 select. PINPOL = 1    Pin is active low. TIMOD   = 3    Single 16-bit counter mode. Timer Compare 1 Register (FLEXIO_TIMCMP1) = 0x0000FFFF TIMCMP = 0x0000FFFF Never compare. Shifter 0 Shifter Control 0 Register (FLEXIO_SHIFTCTL0) TIMSEL = 0    Timer 0 select. TIMPOL = 0    Shift on posedge of Shift clock. PINCFG = 3    Shifter pin output. PINSEL = 0    Shifter pin 0 select. PINPOL = 0    Pin is active high. SMOD    = 2    Transmit mode. Load SHIFTBUF contents into the Shifter on expiration of the Timer. Shifter Configuration 0 Register (FLEXIO_SHIFTCFG0) INSRC   = 0    The input source of the shifter is from a pin. In our cause this doesn’t matter because our shifter is set as transmit mode. SSTOP   = 0    Stop bit disabled. SSTART = 0    Start bit disabled. Once all the FlexIO components are configured you have to enable the FlexIO instance by setting the FLEXEN bit in the FLEX_CTRL register. Initially, the shifter status flag is set and is cleared each time the SHIFTBUF register is written. This flag is set each time the SHIFTBUF data has been transferred to the Shifter (SHIFTBUF is empty).  The shifter status flag 0 is configured to be the trigger of the timer 0, so as soon as the status flag is cleared, the timer 0 will be enabled because TIMENA = 2 ( Timer enabled on Trigger high ) and TRGPOL = 1 (Trigger active low). The shifter will begin to shift out the data on the positive edge of the clock ( TIMPOL = 0) until the timer is disabled. The timer will disable when the timer counter reaches 0 ( TIMDIS = 2). The timer 1 is configured to be active (low) when the timer 0 is enabled. This is because TIMDIS = 1 and TIMENA = 1 . The compare register is configured to 16-bit counter and set to 0xFFFF. With this value the timer will never compare and always be active when the timer is enabled. To send data, you have to make sure that the previous transaction was completed and you can check this by reading the TIMSTAT flag. This flag sets each time the timer counter reaches 0. Once the TIMSTAT flag is set, you clear it and write your new data to the SHITBUF register to start the transaction. The KSDK 1.2.0 has drivers and a HAL to facilitate the configuration of the FlexIO module. Some of the important functions are: FLEXIO_DRV_ Init ( uint32_t instance, const flexio_user_config_t * userConfigPtr ); Use this function to initialize the FlexIO module before using it. In this configuration you can change the settings in the FLEXIO_CTRL register such as: Doze Enable, Debug Enable, Fast Access and software reset. FLEXIO_HAL_ ConfigureTimer ( FLEXIO_Type * base, uint32_t timerIdx , const flexio_timer_config_t * timerConfigPtr ); Use this function to configure a timer in the FlexIO. This function uses a configuration structure that can change the TIMCFG, TIMCTL and TIMCPM registers. FLEXIO_HAL_ ConfigureShifter ( FLEXIO_Type * base, uint32_t shifterIdx , const flexio_shifter_config_t * shifterConfigPtr ); Use this function to configure a shifter in the FlexIO. This function uses a configuration structure that can change the SHIFTCFG and SHIFTCTL registers. FLEXIO_HAL_ SetShifterBuffer ( FLEXIO_Type * base, uint32_t shifterIdx , uint32_t value); Use this function to start a transmission. When writing to the SHIFTBUF register, the Shifter Status Flag is cleared. FLEXIO_DRV_ Start ( uint32_t instance); Use this function to enable the FlexIO module by setting the FLEXEN bit in the FLEX_CTRL register. FLEXIO_HAL_ GetTimerStatusFlags ( FLEXIO_Type * base); This function returns the contents of the TIMSTAT register. You can use this function to check when a transmission is finished. FLEXIO_HAL_ ClearTimerStatusFlags ( FLEXIO_Type * base, uint32_t mask); This function clears a specific Timer Status Flag. You can use this function to clear a flag after you read that the flag was set. To change the frequency of the transmission you have to change the value of the TIMCMP register. In dual 8-bit counters baud/bit mode, the lower 8-bits configures the baud rate divider equal to ( CMP[ 7:0] + 1) * 2 and the upper 8-bits configure the number of bits in each word equal to (CMP[15:8] + 1) / 2. In our example the baud rate divider is set to 4, this means CMP[ 7:0] has the value 1. The number of bits transmitted is set to 8, this means CMP[ 15:8] has the value 0xF. Let’s change the baud rate divider to 32. To obtain the CMP[ 7:0] value, we will have to solve the simple equation: 32 = (CMP[7:0]+1)*2 CMP[7:0] = 15=0xF Now let’s change the number of bits to 16. The CMP[ 15:8] value is defined by: 16 = ((CMP[15:8]+1))/2 CMP[15:8] = 31=0x1F The value for the TIMCMP for the timer 0 has to be 0x00001F0F to get a baud rate divider of 32 and a word length of 16 bits. The waveform will look as follows. Figure 3. 16-bit transmission By default the shifter in the FlexIO transmits the LSB first. To change the transmission order, you have to write to the SHIFTBUFBIS (Bit swapped) register instead of the SHIFTBUF register. There are also other buffer registers: SHIFTBUFBYS and SHIFTBUFBBS. The first register swaps the bytes and the second register swaps the bytes and bits at the same time. When using one of these registers you have to be careful to consider that the length of the SHIFTBUF registers is of 32 bits, so if you choose to use the SHIFTBUFBIS for a transmission and your transmission length is not of 32 bits, you have to start writing your data starting from the most significant bit. The following image shows a MSB transmission. The value 0x6AED0000 was written to the SHIFTBUFBIS register. Figure 4 . MSB 16-bit transmission The FlexIO module supports automatic start and stop bit handling. All you have to do is change the SHIFTCFG and the TIMCFG configuration bits. In the SHIFTCFG register set SSTOP to 11 if you want the stop bit to have the value 1, and set the SSTART to 10 if you want the stop bit to have the value 0. In the TIMCFG register set the TSART to 1 and the TSOP to 10. The transmission will look as the following image. Data transmitted 0x0F. Figure 5. Transmission with start and stop bit Changing the phase of the clock is very easy, you just have to set the TIMPOL bit to 1 in the SHIFTCTL register. Figure 6. Shift on negedge of Shift clock The conditions to disable and enable the timers can be configured by changing the TIMENA and TIMDIS values in the TIMCFG register. In our example the timer is enabled by the trigger high. The trigger can be set to be an external pin, a shifter status flag, or a timer output. In our case the trigger was set to the shifter status flag, but you can change this configuration to your communication needs. The timer can also be enabled when the previous timer is enabled, on a certain pin edge, or with a combination of pins and triggers. The timer in the example above disables on the timer compare. This means that when the timer counter reaches zero, the timer will disable automatically. The timer counter is loaded with the timer compare value every time it reaches zero or when it is first enabled.  The timer can also be disabled by other conditions such as: when the previous timer is disabled, on a trigger falling edge, on a pin edge, or on a combination of these. Each pin can be configured to be active high or low. When a pin polarity is changed it only affects the output of the pin, for example, if a timer is set to be the shifter clock and you change the pin polarity, the shifter clock will not change its polarity, only the output to the pin from the timer will change. The configuration for the polarity of the pins is located in the TIMCTL and SHIFTCTL. When the PINPOL value is changed to 1, the pin is active low. In the following image the polarity of the timer pin and the shifter pin was changed to 1, so they are active low. Figure 7. Timer and Shifter active low The FlexIO module can generate an interrupt from 3 sources: Shifter error, Shifter status flag and Timer status flag. To enable the interrupts you need to set the bits in the SHIFTSIEN ,SHIFTEIEN and TIMIEN. If you are using KSDK you can enable the interrupt in NVIC by setting true . useInt in the FlexIO user config that the function FLEXIO_DRV_Init utilizes. The default handler for the interruption is named UART2_FLEXIO_IRQHandler. The following example configuration will configure the FlexIO module as a receiver. This configuration works with the first example configuration shown. Both tower boards (TWR-KL43Z48M) have to be connected as shown further below in the Table 1 Hardware connnections. The FlexIO module will use one Shifter, one timer, and three pins. The pins will be used for the input of the shifter, the input clock for the timer and the trigger for the timer. The timer will use pin 1 as an input and its output will be the same as the input clock. The trigger for the timer will be the transmitter chip select pin and it will be used to enable or disable the timer. The FlexIO will be configured to do an 8-bit transmission. Shifter 0 Shifter Control 0 Register (FLEXIO_SHIFTCTL0) = 0x00800001 TIMSEL = 0    Timer 0 select. TIMPOL = 1    Shift on negedge of Shift clock. PINCFG = 0    Shifter pin output disabled. PINSEL = 0    Shifter pin 0 select. PINPOL = 0    Pin is active high. SMOD    = 1    Receive mode. Captures the current Shifter content into the SHIFTBUF on expiration of the Timer. Shifter Configuration 0 Register (FLEXIO_SHIFTCFG0) = 0x00000000 INSRC   = 0    The input source of the shifter is from a pin. In our cause this doesn’t matter because our shifter is set as transmit mode. SSTOP   = 0    Stop bit disabled. SSTART = 0    Start bit disabled. Timer 0 Timer Configuration 0 Register (FLEXIO_TIMCFG0) = 0x01206602 TIMOUT = 1    Timer output is logic zero when enabled and is not affected by timer reset. TIMDEC = 2    Decrement counter on Pin input (both edges), Shift clock equals Pin input. TIMRST = 0    Timer never reset. TIMDIS = 6    Timer disabled on Trigger rising edge. TIMENA = 6    Timer enabled on Trigger falling edge. TSTOP   = 0    Stop bit is disabled. TSTART = 1    Start bit enabled. Timer Control 0 Register (FLEXIO_TIMCTL0) = 0x04C00103 TRGSEL = 4    Trigger select. Pin 2 input . TRGPOL = 1    Trigger active low. TRGSRC = 1    Internal trigger selected. PINCFG = 0    Timer pin output disabled. PINSEL = 1    Timer pin 1 select. PINPOL = 0    Pin is active high. TIMOD   = 3    Single 16-bit counter mode. Timer Compare 0 Register (FLEXIO_TIMCMP0) = 0x0000000F TIMCMP = 0x0000000F Configure 8-bit transfer. Set TIMCMP = (number of bits x 2) - 1. The shifter status flag is set every time the SHIFTBUF register has been loaded with data from the shifter. This occurs every time that the transmitter sends 8 bits of data. You can read the shifter status flag by polling or by enabling an interrupt based on your needs. This flag clears automatically when you read the SHITBUF register. During the transmission, the first thing that happens is that timer from the receiver will be enabled because the chip select signal from the transmitter is configured as a trigger. Once the timer is enabled, the timer will begin to decrement on the pin input, this means that the shifter clock of the receiver will be equal to the pin input. The transmitter shifter is configured to shift data out on the positive edge of the clock and the receiver shifter is configured to shift data in on the negative edge of the clock. After 8 bits have been transmitted, the compare register from the receiver will reach 0 and this generates an event to store the data from the shifter to the SHITBUF register and the Shifter Status Flag will be set. Finally the timer will be disabled by the chip select signal and keep waiting for another transaction. The hardware connections are shown in the following table. Signal name TWR-KL43Z48M transmitter TWR-KL43Z48M receiver Pin name Board Location Pin name Board Location Serial Data PTD0/FXIO0_D0 B46 PTD0/FXIO0_D0 B46 Clock PTD1/FXIO0_D1 B48 PTD1/FXIO0_D1 B48 Chip Select PTD2/FXIO0_D2 B45 PTD2/FXIO0_D2 B45 GND GND B2 GND B2 Table 1 . Hardware connections Figure 8 . Hardware connections The example projects for the FlexIO transmitter and receiver are developed in KDS 3.0.0 with KSDK 1.2.0. The application lets the user communicate with the transmitter via a serial terminal and the transmitter sends each character to the receiver via FlexIO and the receiver displays the received character on another serial terminal. To be able to compile the project, first you need to compile the library located in C:\Freescale\KSDK_1.2.0\lib\ksdk_platform_lib\kds\KL43Z4. Once the two TWR-KL43Z48M are connected as described above, import both projects into KDS, compile the platform library, and both projects. Open two serial terminals configured to 115200 bauds and run each project on a different tower. On the transmitter terminal you can write anything and it will be displayed and transmitted to the receiver tower via FlexIO and will be shown on the other terminal. Figure 9 . FlexIO example application. Transmitter (left terminal). Receiver (Right terminal). The FlexIO module is also capable of generating a PWM signal by configuring one of its timers to the Dual 8-bit counters PWM mode. This mode is configured by writing 01 to TIMOD in the TIMCTL register. In this mode, the lower 8-bits of the counter and compare register are used to configure the high period of the timer output and the upper 8-bits are used to configure the low period of the timer output. The shifter bit count is configured using another timer or external signal. To calculate the frequency of the PWM signal you have to add the lower 8-bits of the counter and the upper 8-bits and divide it by the FlexIO clock*2 (Only if the timer is configured to decrement on the FlexIO clock.) The frequency of the PWM signal is given by: f = (FlexIO clock)/(TIMCMP[15:8]+TIMCPM[7:0]+2) To calculate the TIMCMP values to get a certain frequency you can solve the equation for TIMCMP TIMCMP[15:8]+TIMCPM[7:0] = (FlexIO clock)/f-2 For example, let’s say we want a 200kHz PWM signal, by using the formula above and using the FlexIO clock of 48MHz, we get that the sum of the TIMCMP values must be 238. If we want a 50% duty cycle we need to write the value 238/2 to the lower and upper 8 bits of the TIMCMP register. The waveform generated by these settings is shown in the figure below. Figure 10. 200kHz 50% duty cycle PWM signal To change the duty cycle you need to change the values of TIMCPM[ 15:8] and TIMCPM[7:0] but without changing the sum of both values, otherwise the frequency will also be altered. For example, if we need a 20% duty cycle we multiply 0.20*238 and 0.8*238. We round up the results and get TIMCPM[ 7:0] = 48 and TIMCPM[15:8] = 190. The waveform generated will look as shown in the figure below. Figure 11. 200kHz 20% duty cycle PWM signal
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Hi All Kinetis Lovers, Microcontroller programming is a passion for all we are following this Community, but sometimes, trying to understand the peripherals of a Microcontroller is not an easy task, especially if we are in our first approach to a new module or device. In this post you will find a document that explains in detail the DMA module for Kinetis devices and also some examples for CodeWarrior and Kinetis Design Studio using DMA and other peripherals. The Documentation found here is: Using DMA module in Kinetis devices (complete): Document that includes DMA module explanation: everything you need to know when using DMA and the necessary information to understand the code included (K20_DMA for CW or K20D72_DMA for KDS). Using DMA module in Kinetis devices (example): Document that includes the necessary information to understand the code included (K20_DMA for CW or K20D72_DMA for KDS). Attached are two folders named: DMA examples for CW: include the DMA example projects for CW DMA examples for KDS: include the DMA example projects for KDS. Each folder includes 5 examples that are: Please feel free to modify the examples; I hope this will be useful for you. Many thanks and credits to manuelrodriguez for his valuable help developing and editing this project. :smileyinfo:For the SPI examples it is necessary to make a bridge between MOSI and MISO pins (master loop mode is used for the example). For this the TWR Elevators were used.     In the attachments you can find some extra information when using SPI and DMA. Best Regards, Adrian Sanchez Cano Technical Support Engineer
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Hi community!! The following example uses a PIT to start an adc conversion, once the conversion has finished it issues a DMA request and the DMA controller stores the converted value in a buffer. The examples were implemented in both CodeWarrior 10.6 and KDS 1.1 for every board. The recommended test circuit is the following: Please feel free to modify the files, I hope this examples will be useful for you and will help you by decreasing your development time. Best Regards Manuel Rodríguez Technical Information Center Intern
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1. How Calibration works There are three main sub-blocks important in understanding how the Kinetis SAR module works.  There is a capacitive DAC, a comparator, and the SAR engine that controls the module. Of those blocks, the DAC is most susceptible to variations that can cause linearity problems in the SAR. The DAC is architected with three sets of binary weighted capacitors arrayed in banks, as in Figure 1. The capacitors that represent the most significant bits of the SAR (B15:B11) are connected directly to the inputs of the comparator. The next bank of five capacitors (B10:B6) is connected to the top plate of the MSB array through an intentionally oversized scaling capacitor. The final six capacitors that makeup the least significant bits of the SAR (B5:B0) are correspondingly connected to the top plate of the middle bank of capacitors through another scaling capacitor. Figure 1. Arrangement of DAC capacitors Only the MSB capacitor bank is calibrated. Because the first scaling capacitor is intentionally oversized, each of the non-calibrated MSB capacitors will have an effective capacitance too small to yield accurate results. However, because they are always too small, we can measure the amount oferror that each of those capacitors would cause individually, and add that back in to the result. Calibration starts with the smallest of the LSB capacitors, B11. The SAR samples Vrefl on all of the capacitors that are lower-than or equal-to the capacitor under test (CUT), while connecting all of the smaller capacitors to Vrefh. The top plate of all of the MSB capacitors is held at VDDA while this happens. After the sampling phase is complete, the top plates of the MSB capacitors are allowed to float, and the bottom plates of the MSBs not under test are connected to Vrefl. This allows charge to redistribute from the CUT to the smaller capacitors. Finally, an 11 bit SAR algorithm (corresponding with the 11 capacitors that are smaller than the MSB array) is performed which produces a result that indicates the amount of error that the CUT has compared to an ideally sized capacitor. This process is repeated for each of the five MSBs on both the plus side and minus side DACs and the five error values that are reported correspond to the five MSBs accordingly. All of these error values are about the same magnitude, with a unit of 16-bit LSBs. See Figure 2 for an example. Figure 2. Example of calibration on bit 11 The DAC MSB error is cumulative. That is, if bit 11 of the DAC is set, then the error is simply the error of that bit. However if bit 12 of the DAC is set, the total error is equivalent tothe error reported on bit 12, plus the error reported on bit 11. For each MSB the error is calculated as below, where Ex is the error found during the calibration for its corresponding MSB bit: When bit 11 of the DAC is set: CLx0 = E0. When bit 12 of the DAC is set: CLx1 = E0+E1. When bit 13 of the DAC is set: CLx2 = E2 + E1 + 2E0. When bit 14 of the DAC is set: CLx3 = E3 + E2 + 2E1 + 4E0. When bit 15 of the DAC is set: CLx4 = E4 + 2E3 + 4E2 + 8E1 + 16E0 Figure 3. Effect of calibration error on ADC response These are the values that are then placed in each of the CLxx calibration results registers. Figure 3 shows how the errors would accumulate if all of the CLxx registers were set to zero. The offset and gain registers are calculated based on these values as well. Because of this, the gain and offset registers calibrate only for errors internal to the SAR itself. Self calibration does not compensate for board or system level gain or offset issues . 2. Recommended Calibration Procedure From the above description it is evident that the calibration procedure is in effect several consecutive analog to digital conversions. These are susceptible to all of the same sources of error of any ADC conversion. Because what is primarily being measured is the error in the size of the MSB capacitors; the recommendation is to configure the SAR in such a way as to make for the most accurate conversions possible in the environment that the SAR is being calibrated in. Noise is the primary cause of run-to-run variation in this process,so steps should be taken to reduce the impact of noise during the calibration process. Such as: All digital IO should be silent and unnecessary modules should be disabled. The Vrefh should be as stable and high a voltage as possible, since higher Vrefh means larger ADC code widths. An isolated Vrefh pin would be ideal. Lacking that, using an isolated VDDA as the reference would be preferable to using VREFO. The clock used should be as noise free as possible, and less than or equal to 6 MHz. For this purpose the order of desirable clock sources for calibration would be OSC > PLL > FLL > ASYNC The hardware averaging should be set to the maximum 32 samples. The Low Power Conversion bit should be set to 0. The calibration should be done at room temperature. The High Speed Conversion and Sample Time Adder will not have much effect in most situations, and the Diff and Mode bits are completely ignored by the calibration routine. The calibration values should be taken for each instance of the SAR on a chip in the above conditions. They should be stored in nonvolatile memory and then written into their appropriate registers whenever the ADC register values are cleared. In some instances, the system noise present will still cause the calibration routine to exhibit greater than desired run-to-run variation. One rule of thumb would be to repeat calibration several times and look at the CLx0 registers. If the value reported in that register varies by more than three, the following procedure can be implemented. Run the calibration routine several times. Twenty to forty times. Place the value of each of the calibration registers into a corresponding array. Perform a bubble sort on each array and find the median value for each of the calibration registers. Use  these median values as described for typical calibration results.
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Revise History: Version 23: NXP kinetis bootloader GUI upgrade from v1.0 to v1.1: added 04 extended linear address record  and 02 sector address record processing for hex format. This article describes how to do in-system reprogramming of Kinetis devices using standard communication media such as SCI. Most of the codes are written in C so that make it easy to migrate to other MCUs. The solution has been already adopted by customers. The pdf document is based on FRDM-KL26 demo board and Codewarrior 10.6.  The bootloader and user application source codes are provided. GUI and video show are also provided. Now the bootloader source code is ported to KDS3.0, Keil5.15 and IAR7.40 which are also enclosed in the SW package. Customer can make their own bootloader applications based on them. The application can be used to upgrade single target board and multi boards connected through networks such as RS485. The bootloader application checks the availability of the nodes between the input address range, and upgrades firmware nodes one by one automatically. ​ Key features of the bootloader: Able to update (or just verify) either single or multiple devices in a network. Application code and bootloader code are in separated projects, convenient for mass production and firmware upgrading. Bootloader code size is small, only around 2K, which reduces the requirement of on chip memory resources. Source code available, easy for reading and migrating. GUI supports S19,HEX and BIN format burning images. For more information, please see attached document and code. The attached demo code is for KL26 which is Cortex - M0+ core. For Cortex-M4 core demo, refer this url: https://community.freescale.com/docs/DOC-328365 User can also download the document and source code from Github: https://github.com/jenniezhjun/Kinetis-Bootloader.git Thanks for the great support from Chaohui Guo and his team. NOTE: The bootloader and GUI code are all open source, users can revise them based on your own requirement. Enjoy Bootloader programming 🙂
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For Remote Control means, that is needed two computers - Server Computer and User Computer, which will be in connection. There are two types of connection, which can be used - HTTP or DCOM. There are two different ways how to set up the remote control in Windows. I made the tutorial, which describes both types of Remote Control. Ok - so, let´s start! HTTP Settings On the Server Computer side: 1. Plug the board to the Server Computer 2. Go to Remote Communication Server 3. Set HTTP connection and choose the right COM Port according the plugged board If the plugged board is on e.g. COM23, it is possible to edit number of Port in Device Manager On the User PC side: 1. Open FreeMASTER,  go to Project -> Options 2. Choose Plug-in Module: FreeMASTER CommPlugin for Remote Server (HTTP) and type the IP address of the server, do not forget join to IP address :8080 3. And start communication by STOP button to successful connection DCOM Settings On the Server Computer side: 1. Plug board to the Server Computer 2. Launch DCOM in FreeMASTER Remote Server Choose COM according plugged board or edit COM according to step 2 - Server Computer in HTTP Connection (up). 3. Setting permissions for the user, User PC. Right click on Computer -> Manage. In Computer Management click to Distributed COM Users. In Distributed COM Users Properties add the user, User Computer. After that, set the permissions in Component Services. In cmd type dcomcnfg.exe In Component Services go to Computers -> My Computer -> DCOM Config -> MCB FreeMASTER Remote Server Application Right click on MCB FreeMASTER Remote Server Application and go to Properties. In Security Tab is possible to add the permissions. There are 3 types of permissions. First permission - Launch and Activation Permissions. There are 4 permission options. Local Launch and Remote Launch means, that user, User Computer can launch e.g. FM Remote Server Application. But for success communication is needed allowing Local Activation and Remote Activation. Second permission - Access Permissions. Click to Edit and Allow Local Access and Remote Access for the user. Do not forget that if there is a change of permissions, specifically allowing, it is necessary for User to log out and log in. On the User Computer side: 1. Open Freemaster, go to Project -> Options 2. Choose Plug-in Module: FreeMASTER CommPlugin for Remote Server (DCOM) and for filling Connect string is possible to use Configure. Definitely, type the IP address of the server and ;Port Name. 3. And start communication by STOP button in FreeMASTER to successful connection And now.. you can do anything 🙂
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Introduction This document is being written to communicate the need for serialization of memory operations and events in an end application.  In addition, directions will be provided to properly serialize memory operations in the end application.  Memory operations and event serialization applies to all Kinetis devices but is only necessary in specific scenarios. These scenarios include memory writes and reads, clearing status flags, and changing mode control operations. Serialization of memory operations Serialization of memory operations or events is the action of guaranteeing that said memory operations or events are executed in a specific order.  This action is required when making a change to a peripheral module when that change must complete before continuing with program execution.  Users often make the mistake of assuming that since a peripheral register has been written to, the change is in effect immediately.  However, this is not always the case.  The Kinetis series devices implement a crossbar and peripheral bridge interface system that allows masters (the CPU, DMA, etc.) to interface with the peripherals.  The crossbar allows multiple masters to access the individual peripherals on the bus, and the peripheral bridge functions as a bus protocol translator between the crossbar switch and the slave peripheral bus.  Wait states can be inserted at either stage of the communication channel (crossbar or peripheral bridge).  When a master attempts to access a slave and another master is already accessing this slave or the slave is busy, wait states will be inserted.  If the access is a write, then the master's write is simply pushed to the peripheral bus and the master continues.  However, if the access is a read, the master must wait for a response from the slave.  The slave may insert wait states in this communication as it must finish any commands (or writes) it was previously given before responding.    Peripheral module changes that require serialization actions include clearing interrupt service flags, changing power modes (of the module or the SOC as a whole), or software triggering a hardware event.  If the events or memory operations are not serialized in these situations, the CPU could go on to execute code with undesired effects. When do I need to serialize my memory operations and events? Memory operations and events require serialization anytime the program needs to guarantee that a peripheral access happens before code execution continues.  Examples of these situations includes: Exiting an interrupt service routine (ISR) Changing a clock mode or power mode Configuring a function Configuring a hardware change Software triggering a hardware event How do I serialize my memory operations and events? Memory operations are serialized by performing the following operations: Write the desired peripheral register Read the peripheral register that was just written Continue with the subsequent operations By simply reading the register that was just written, the core is forced to wait for a response from the peripheral module that was written before code execution can continue.   In this manner, it is guaranteed that the peripheral module will have completed the desired operations. Example event serialization The following is an example of a function that services the LPTMR ISR flag and implements the event serialization discussed in this document.  void lptmr_isr(void) {   // Declare dummy variable to store the read of the LPTMR0_CSR register volatile int dummy_var; /****   STEP #1  ****/   // Clear the flag; enable interrupts; enable the timer   LPTMR0_CSR = ( LPTMR_CSR_TEN_MASK | LPTMR_CSR_TIE_MASK | LPTMR_CSR_TCF_MASK  );   /****  STEP #2  ****/    // Store CSR register in dummy_var to serialize the clearing of the TCF flag   dummy_var = LPTMR0_CSR; } Conclusion In conclusion, there are situations where code execution can continue before a peripheral change has taken effect. These situations include clearing interrupt service flags, changing power modes (of the module or the SOC as a whole), or software triggering a hardware event.   Sometimes these events can cause unexpected results or even cause your application to crash.  These situations call for the serialization of memory operations and events, which is simply the act of guaranteeing that events and code are executed in a specific order.  To serialize memory operations, simply follow these directions: Write the desired peripheral register Read the peripheral register that was just written Continue with the subsequent operations Following these steps, you will be guaranteed that peripheral configurations have taken effect before continuing with the application. 
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for M68HC08, HCS08, ColdFire and Kinetis MCUs by: Pavel Lajsner, Pavel Krenek, Petr Gargulak Freescale Czech System Center Roznov p.R., Czech Republic The developer's serial bootloader offers to user easiest possible way how to update existing firmware on most of Freescale microcontrollers in-circuit. In-circuit programming is not intended to replace any of debuging and developing tool but it serves only as simple option of embedded system reprograming via serial asynchronous port or USB. The developer’s serial bootloader supported microcotrollers includes 8-bit families HC08, HCS08 and 32-bit families ColdFire, Kinetis. New Kinetis families include support for K series and L series. This application note is for embedded-software developers interested in alternative reprogramming tools. Because of its ability to modify MCU memory in-circuit, the serial bootloader is a utility that may be useful in developing applications. The developer’s serial bootloader is a complementary utility for either demo purposes or applications originally developed using MMDS and requiring minor modifications to be done in-circuit. The serial bootloader offers a zero-cost solution to applications already equipped with a serial interface and SCI pins available on a connector. This document also describes other programming techniques: FLASH reprogramming using ROM routines Simple software SCI Software for USB (HC08JW, HCS08JM and MCF51JM MCUs) Use of the internal clock generator PLL clock programming EEPROM programming (AS/AZ HC08 families) CRC protection of serial protocol option NOTE: QUICK LINKS The Master applications user guides: Section 10, Master applications user guides. The description of Kinetis version of protocol including the changes in user application: Section 7, FC Protocol, Version 5, Kinetis. The quick start guide how to modify the user Kinetis application to be ready for AN2295 bootloader: Section 7.8, Quick guide: How to prepare the user Kinetis application for AN2295 bootloader. Full application note and  software attached.
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The Real Time Clock (RTC) module is the right tool when we want to keep tracking the current time for our applications. For the Freedom Platform (KL25Z) the RTC module features include: 32-bit seconds counter with roll-over protection and 32-bit alarm 16-bit prescaler with compensation that can correct errors between 0.12 ppm and 3906 ppm. Register write protection. Lock register requires POR or software reset to enable write access. 1 Hz square wave output. This document describes how to implement the module configuration. Also, how to modify the hardware in order feed a 32 KHz frequency to RTC module (it is just a simple wire link).     Hardware. The RTC module needs a source clock of 32 KHz. This source is not wired on the board; hence we need to wire it. Do not be afraid of this, it is just a simple wire between PTC3 and PTC1 and the good news are that these pins are external.   PTC1 is configured as the RTC_CLKIN it means that this is the input of source clock.     PTC3 is configured as CLKOUT (several options of clock frequency can be selected in SIM_SOPT2[CLKOUTSEL] register). For this application we need to select the 32 Khz clock frequency.                         RTC configuration using Processor Expert. First of all we need to set the configurations above-mentioned in Component Inspector of CPU component. Enable RTC clock input and select PTC1 in Pin Name field. This selects PTC1 as RTC clock input. MCGIRCLK source as slow in Clock Source Settings > Clock Source Setting 0 > Internal reference clock > MCGIRCLK source. This selects the 32 KHz clock frequency. Set ERCLK32K Clock Source to RTC Clock Input in Clock Source Settings > Clock Source Setting 0 > External reference clock > ERCLK32K Clock Source. This sets the RTC_CLKIN as the 32 KHz input for RTC module. Select PTC3 as the CLKOUT pin and the CLKOUT pin output as MCGIRCLK in Internal peripherals > System Integration Module > CLKOUT pin control. With this procedure we have a frequency of 32 KHz on PTC3 and PTC1 configured as RTC clock-in source. The MCG mode configurations in this case is PEE mode: 96 MHz PLL clock, 48 MHz Core Clock and 24 MHz Bus clock.   For the RTC_LDD component the only important thing is to select the ERCKL32K as the Clock Source. The image below shows the RTC_LDD component configuration for this application.   After this you only need to Generate Processor Expert Code and write your application.  The code of this example application can be found in the attachments of the post. The application prints every second the current time.     RTC bare-metal configuration. For a non-PEx application we need to do the same configurations above. Enable the internal reference clock. MCGIRCLK is active.          MCG_C1 |= MCG_C1_IRCLKEN_MASK; Select the slow internal reference clock source.          MCG_C2 &= ~(MCG_C2_IRCS_MASK); Set PTC1 as RTC_CLKIN and select 32 KHz clock source for the RTC module.          PORTC_PCR1 |= (PORT_PCR_MUX(0x1));              SIM_SOPT1 |= SIM_SOPT1_OSC32KSEL(0b10); Set PTC3 as CLKOUT pin and selects the MCGIRCLK clock to output on the CLKOUT pin.     SIM_SOPT2 |= SIM_SOPT2_CLKOUTSEL(0b100);     PORTC_PCR3 |= (PORT_PCR_MUX(0x5));   And the RTC module configuration could be as follows (this is the basic configuration just with seconds interrupt): Enable software access and interrupts to the RTC module.     SIM_SCGC6 |= SIM_SCGC6_RTC_MASK; Clear all RTC registers.   RTC_CR = RTC_CR_SWR_MASK; RTC_CR &= ~RTC_CR_SWR_MASK;   if (RTC_SR & RTC_SR_TIF_MASK){      RTC_TSR = 0x00000000; } Set time compensation parameters. (These parameters can be different for each application) RTC_TCR = RTC_TCR_CIR(1) | RTC_TCR_TCR(0xFF); Enable time seconds interrupt for the module and enable its irq. enable_irq( INT_RTC_Seconds - 16); RTC_IER |= RTC_IER_TSIE_MASK; Enable time counter. RTC_SR |= RTC_SR_TCE_MASK; Write to Time Seconds Register. RTC_TSR = 0xFF;   After this configurations you can write your application, do not forget to add you Interrupt Service Routine to the vector table and implement an ISR code.   In the attachments you can find two zip files: PEx application and non-PEx application.   I hope this could be useful for you,   Adrián Sánchez Cano. Original Attachment has been moved to: FRDM-KL25Z-RTC-TEST.zip Original Attachment has been moved to: FRDM-KL25Z-PEx-RTC.zip
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Porting FatFs file system to KL26 SPI SD card code 1 Abstract      Without the SDHC module, Kinetis KL series need to use the SPI interface to communicate with the SD card. Normally, when customer use the SD card, they are not only want to write and read the SD card, but also prefer to create files(eg, text file, csv file,etc.) in the SD card to record some important data. Use the file to record the data, then the data can be read easily by the PC. MCU need to use the file system to operate the files, the file system should realize the function of file creating, file deleting, file reading and writing, etc. FatFs is a generic FAT/exFAT file system module for small embedded systems. This document mainly describe how to port a FatFs file system to the KL26 SPI SD card code, SD card SPI interface hardware circuit and the SD card basic operation code. 2 FatFs file system introduction 2.1 FatFs feature Windows compatible FAT/exFAT file system. Platform independent. Easy to port. Very small footprint for program code and work area. Various configuration options to support for: Multiple volumes (physical drives and partitions). Multiple ANSI/OEM code pages including DBCS. Long file name in ANSI/OEM or Unicode. exFAT file system. RTOS envilonment. Fixed or variable sector size. Read-only, optional API, I/O buffer and etc... 2.2 FatFs file system organizations   From the above pictures, we can see that in a project with Fatfs module, there mainly 4 parts: application, Fatfs, Disk I/O layer and the Media(SD card). (1) Application, user just need to call the FatFs API function to realize the file creation, read, write and delete. (2) FatFs module, this module contains 6 important files which customer need to use, it is: diskio.c, diskio.h, ff.c, ff.h, ffconf.h, integer.h.  diskio.c and diskio.h is used to call the SD card operation function from the Disk I/O layer, user need to modify this file to match the disk I/O layer, or write the disk I/O layer match this file. ff.c,ff.h is the FatFs file system layer, it defines the API function, user don’t need to modify it. ffconf.h is the system configuration file. integer.h is the data type define file, user don’t need to modify these two files. (3) Disk I/O layer, there has mmc.c and spi.c, actually, the detail name can be defined by the user, it is not fixed. Mmc.c is used to realize the SD card function, eg, SD initialization, SD block writing and reading.  Spi.c is the MCU SPI interface file, it realize the SPI communication function, because the Kinetis series don’t have the SDHC interface, then it use the SPI interface to communicate with the SD card. (4) Media, it can be SD,MMC, USB, NAND flash, here we use the SD card. More details, please refer to FatFs Module application note. 2.3 Common API function f_mount - Register/Unregister a work area of a volume f_open - Open/Create a file f_close - Close an open file f_read - Read data f_write - Write data f_lseek - Move read/write pointer, Expand size f_truncate - Truncate size f_sync - Flush cached data More functions, please go to this link: http://elm-chan.org/fsw/ff/00index_e.html 3 SPI SD operation 3.1 Hardware       This document use the YL_KL26 as the testing board, customer also can add an external SD card circuit to the FRDM-KL26 board. The board is using the TF card, SD SPI interface circuit is:   The pin assignment in the YL-KL26 board is defined as follows: KL26 pin SPI name PTC4 SPI_CS0 PTC5 SPI_SCK PTC6 SPI_MOSI PTC7 SPI_MISO 3.2 Softwave      The test code project is based on the MDK5.1x. 3.3 SD I/O Layer 3.3.1 SD card initialization The communication speed for SD card initialization can’t exceed 400kb/s, if the speed is higher than 400kbps, user need to add the delay in the initialization code, otherwise the initialization will be failure. After the initialization is successful, user can increase the SD card communication speed. Initialization process: (1)  Initialize the SPI interface which connect to the SD card, down to low speed. (2)  Power on delay 72clks, wait for the SD card ready (3)  Go idle state, CMD0, this command will trigger the SD card to use the SPI interface. (4)  Get SD card information, CMD8, get the SD card version. (5) Active the SD card,  with CMD55+CMD41 (6) Read OCR data,CMD59. (7) Set SD card block size to 512Byte. CMD16 (8) Read CSD, get other information, CMD9 (9) Change to high speed and disable the CS uint8 MMCInit(void) {                 uint8 i = 0,k = 0,tmp = 0;                 uint16 cnt=0;                 uint8  buff[512];                                 SSP0LowSpeed();                                      // low speed                 MMCDelayUs(5000);                                                                                   for (i=0; i<0x0F; i++)                               {                    Send_Byte(0xFF);          // send 72 clocks                 }                 // Send Command CMD0 to SD/SD Card  enter idle                 do                 {                     tmp = MMCWriteCmd(CMD0,0x00,0x95);   // CMD0                      k++;                 }while ((tmp != 1) && (k < 200));                                   if(k == 0)                 {                   MMCCS(1);           //cs pullup, disconnect                   Send_Byte(0xFF);                   printf("\n SD reset fail");                   return 1;//                 }                                              //get SD card version                  tmp = MMCWriteCmd( CMD8,0x1AA,0x87 );                  printf( "SD_CMD8  return  %d........\n\n", tmp );  if(tmp == 1)// 2.0 card {          cnt=0xffff;                    do    {     MMCWriteCmd( CMD55, 0, 0xff );     tmp = MMCWriteCmd( CMD41,0x40000000, 0xff);//CMD41      cnt--;    } while ((tmp) && (cnt));                  //Get OCR information                  tmp = MMCWriteCmd(CMD58, 0, 0 );    if ( tmp != 0x00 )    {                   MMCCS(1);           //cs pullup, SD card disconnect                                 printf( "\nSD_CMD58 return  %d....\n", tmp );                   return 1;//    }      for ( i = 0; i < 4; i++ )    {     buff[ i ] = Get_Byte();    }    MMCCS(1);    printf( "OCR return: %x %x %x %x....\n\n", buff[0],buff[1],buff[2],buff[3] );      if ( buff[0] & 0x40 )    {                                  SD_Type = SD_TYPE_V2HC;      printf( "card is V2.0 SDHC.....\n\n" );    }    else {                                  SD_Type = SD_TYPE_V2;      printf( "card is V2.0.....\n\n" );    }              while(MMCWriteCmd(CMD16,512,0xff)!=0);                  MMCWriteCmd(CMD9,0,0xff);   }                 SSP0HighSpeed();                    //back to high speed                 MMCCS(1);                             return 0;                        } 3.3.2 Read one SD card block The block size is 512Byte, the read process is: Send CMD17 and wait the response Receive the start token 0XFE Receive the 512Byte data Receive 2 bytes CRC Disable the CS pin   uint8 MMCReadSingleBolck(uint32 addr,uint8 *buf) {                 uint16 i;                 uint8 sta;                 if(SD_Type!=SD_TYPE_V2HC)                 {                       addr= addr<<9;                 }                 sta = MMCWriteCmd(CMD17,addr,0x01);                 while(sta !=0)                 {                   sta = MMCWriteCmd(CMD17,addr,0x01);                 }                   while (Get_Byte() != 0xFE){;}                   if(sta == 0)                 {                   for (i=0; i<512; i++)                        {                     buf[i] = Send_Byte(0xFF);                   }                            }                 Send_Byte(0xFF);                                                                  Send_Byte(0xFF);                 MMCCS(1);                 return 0; } 3.3.3 Read multiple SD card block uint8 MMCReadMultipleBolck(uint32 addr,uint8 *buf,uint8 count) {          uint16 i;                 if(SD_Type!=SD_TYPE_V2HC)                 {                     addr= addr<<9;                 }                                                 if (MMCWriteCmd(CMD18,addr,0xFF) != 0x00)                    {                     return 1;                                          }                                 MMCCS(0);                 do                 {                     while (Send_Byte(0xFF) != 0xFE){;}                     for (i=0; i<512; i++)                                         {                         *buf++ = Send_Byte(0xFF);                     }                     Send_Byte(0xFF);                                                                                         Send_Byte(0xFF);                                 }while (--count);                 MMCCS(1);                 MMCWriteCmd(CMD12,0x00,0xFF);                   Send_Byte(0xFF);//delay                 return 0; } 3.3.4 Write one SD card block The procedure is: Send CMD24 and wait the response Receive the start token 0XFE Send the 512Byte data Send 2 bytes CRC Disable the CS pin   uint8 MMCWriteSingleBlock(uint32 addr,const uint8 *buf) {                 uint16 i,retry ;                 uint8  temp;                                 if(SD_Type!=SD_TYPE_V2HC)                 {                      addr=addr<<9 ;                 }                                              if (MMCWriteCmd(CMD24,addr,0x01) != 0x00)                         {                     return 1;                                                  }                 MMCCS(0);                 //wait SD card ready                 Send_Byte(0xFF);                          Send_Byte(0xFF);                 Send_Byte(0xFF);                 Send_Byte(0xFE);                               for (i=0; i<512; i++)                                 {                     Send_Byte(buf[i]);                 }                 //Dummy CRC                 Send_Byte(0xFF);                                                                              Send_Byte(0xFF);                 temp = Send_Byte(0xFF);                                                        temp &= 0x1F;                        if (temp != 0x05)                 {                     MMCCS(1);                     return 1;                                                                                                  }                                                 while (Send_Byte(0xFF) == 0x00)                 {                      retry++;                      if(retry>0xfffe)                     {                       MMCCS(1);                        return 1 ;                      }                 }                 MMCCS(1);                 Send_Byte(0xFF);                 return 0; } 3.3.5 Write multiple SD card block uint8 MMCReadMultipleBolck(uint32 addr,uint8 *buf,uint8 count) {     uint16 i;                 if(SD_Type!=SD_TYPE_V2HC)                 {                                   addr= addr<<9;                 }                                                 if (MMCWriteCmd(CMD18,addr,0xFF) != 0x00)                    {                     return 1;                                          }                                 MMCCS(0);                 do                 {                     while (Send_Byte(0xFF) != 0xFE)                     {                         ;                                                                                    }                                     for (i=0; i<512; i++)                                         {                         *buf++ = Send_Byte(0xFF);                     }                                     Send_Byte(0xFF);                                                                                         Send_Byte(0xFF);                                 }while (--count);                                 MMCCS(1);                 MMCWriteCmd(CMD12,0x00,0xFF);                   Send_Byte(0xFF);//delay                 return 0; } 4 FatFs file system porting 4.1 FatFs source code download Go to FatFs official website download the source code, the link is: http://elm-chan.org/fsw/ff/00index_e.html The latest version is FatFs R0.12.    Unzip it, like the following picture, just need 6 files, user can copy it to the project SPI driver folder, and create a new folder named as fatfs. 4.2 Modify diskio.c file We need to modify these functions: disk_initialize:Disk initialize disk_status     :Get the Disk status disk_read       :Read Disk block disk_write      :Write Disk block disk_ioctl       :control device character get_fattime    :Get current time 4.2.1 disk_initialize function DSTATUS disk_initialize (                 BYTE pdrv                                                 ) {                 DSTATUS stat;                    stat=MMCInit();  //SD card initialization                  if(stat == STA_NODISK)                    {                         return STA_NODISK;                     }                 else if(stat != 0)                   {                         return STA_NOINIT;                   }               else                {                      return 0;                         } } 4.2.2 disk_status  function DSTATUS disk_status (                 BYTE pdrv                 /* Physical drive nmuber to identify the drive */ ) {        if(pdrv)     {         return STA_NOINIT;      }                 return RES_OK; } 4.2.3 disk_read function DRESULT disk_read (                 BYTE pdrv,                                /* Physical drive nmuber to identify the drive */                 BYTE *buff,                               /* Data buffer to store read data */                 DWORD sector,        /* Sector address in LBA */                 UINT count                               /* Number of sectors to read */ ) {     DRESULT res;     if (pdrv || !count)     {            return RES_PARERR;      }                           if (count == 1)                  {                                 res = MMCReadSingleBolck(sector,buff);                 }                 else                           {                                 res = MMCReadMultipleBolck(sector,buff,count);                 }     if(res == 0x00)     {         return RES_OK;     }     else     {         return RES_ERROR;     } } 4.2.4 disk_write function DRESULT disk_write (                 BYTE pdrv,                                                /* Physical drive nmuber to identify the drive */                 const BYTE *buff,      /* Data to be written */                 DWORD sector,                        /* Sector address in LBA */                 UINT count                                               /* Number of sectors to write */ ) {                 DRESULT res;                   if (pdrv || !count)     {            return RES_PARERR;      }     if(count == 1)     {         res = MMCWriteSingleBlock(sector, buff);     }     else     {         res = MMCWriteMultipleBlock(sector, buff, count);     }     if(res == 0)     {         return RES_OK;     }     else     {         return RES_ERROR;     } }   4.2.5 disk_ioctl function DRESULT disk_ioctl (                 BYTE pdrv,                                /* Physical drive nmuber (0..) */                 BYTE cmd,                /* Control code */                 void *buff                /* Buffer to send/receive control data */ ) {                 DRESULT res;                 BYTE n, csd[16];                 DWORD csize;                  if (pdrv)                  {                         return RES_PARERR;                  }                 res = RES_ERROR;                 switch (cmd)                 {                     case CTRL_SYNC       : res = RES_OK; break;                     case GET_SECTOR_COUNT: /* Get number of sectors on the disk (WORD) */                                                                 if((MMCWriteCmd(0x49,0x00,0x95) == 0) && MMCCSD_CID(0x49, csd))                                                                 {                                                                 if((csd[0] >> 6) == 1) /* SDC ver 2.00 */                                                                 {                                                                 csize = csd[9] + ((WORD)csd[8] << 😎 + 1;                                                                 *(DWORD*)buff = (DWORD)csize << 10;                                                                 }                                                                 else /* MMC or SDC ver 1.XX */                                                                 {                                                                 n = (csd[5] & 15) + ((csd[10] & 128) >> 7) + ((csd[9] & 3) << 1) + 2;                                                                 csize = (csd[8] >> 6) + ((WORD)csd[7] << 2) + ((WORD)(csd[6] & 3) << 10) + 1;                                                                 *(DWORD*)buff = (DWORD)csize << (n - 9);                                                                 }                                                                 res = RES_OK;                                                                 }                                                                 break;                     case GET_SECTOR_SIZE : /* Get sectors on the disk (WORD) */                                                                    *(WORD*)buff = 512;                                                                    res = RES_OK;                                                                    break;                     case GET_BLOCK_SIZE  :                                                             if ((MMCWriteCmd(0x49,0x00,0x95) == 0) && MMCCSD_CID(0x49, csd)) /* Read CSD */                                                        {                              *(DWORD*)buff = (((csd[10] & 63) << 1) + ((WORD)(csd[11] & 128) >> 7) + 1) << ((csd[13] >> 6) - 1);                                                                        res = RES_OK;                                                        }                                            break;                       default              : res = RES_PARERR; break;                 }                   return res; } 4.2.6 Get_fattime function   This function is used to get the current time, and write it in the file attribute when create, modify the files. It should associate with the RTC, this project didn’t add this function, so just write the code like this: DWORD get_fattime (void) { return 0; } 4.2.7 include SD.h file Comment usb, ATA include files, and add the user SD.h file, this is the SD card IO layer header file. #include "diskio.h"                   /* FatFs lower layer API */ //#include "usbdisk.h"              /* Example: Header file of existing USB MSD control module */ //#include "atadrive.h"            /* Example: Header file of existing ATA harddisk control module */ //#include "sdcard.h"                               /* Example: Header file of existing MMC/SDC contorl module */ #include "SD.h " /* Definitions of physical drive number for each drive */ //#define ATA                           0              /* Example: Map ATA harddisk to physical drive 0 */ //#define MMC                        1              /* Example: Map MMC/SD card to physical drive 1 */ //#define USB                          2              /* Example: Map USB MSD to physical drive 2 */ 4.3 Modify main function This project function is to create two files: Test.csv and Test.txt.  Write four items in these files: Test1, Test2, Test3, Test4. int main (void) {                 uint16 i,j;                 FATFS fs;                               FRESULT fr;                 FIL          fil;                                                            UINT bw;                 char file_name1[12]="Test.csv";                 char file_name2[12]="Test.txt";                 System_init();                 spiInit(SPI0_BASE_PTR , Master);                 fr= f_mount(&fs,file_name1,0);                 if(fr)                 {                                 printf("\nError mounting file system\r\n");                                 for(;;){}                 }                 fr = f_open(&fil, file_name1, FA_WRITE | FA_OPEN_ALWAYS);//create csv file                 if(fr)                 {                                 printf("\nError opening text file\r\n");                                 for(;;){}                 }                 fr = f_write(&fil, "Test1 ,Test2 ,Test3 ,Test4 \r\n", 29, &bw); //write data to the excel file                 if(fr)                 {                                 printf("\nError write text file\r\n");                                 for(;;){}                 }                  fr = f_close(&fil);                 if(fr)                 {                                 printf("\nError close text file\r\n");                                 for(;;){}                 }                 fr= f_mount(&fs,file_name2,0);                 if(fr)                 {                                 printf("\nError mounting file system\r\n");                                 for(;;){}                 }                              fr = f_open(&fil, file_name2, FA_WRITE | FA_OPEN_ALWAYS);//create txt file                 if(fr)                 {                                 printf("\nError opening text file\r\n");                                 for(;;){}                 }                 fr = f_write(&fil, "Test1 ,Test2 ,Test3 ,Test4 \r\n", 29, &bw); //write data to the txt file                 if(fr)                 {                                 printf("\nError write text file\r\n");                                 for(;;){}                 }                 fr = f_close(&fil);                 if(fr)                 {                                 printf("\nError close text file\r\n");                                 for(;;){}                 }            while(1)                 {                          for(i=0;i<10;i++) for(j=0;j<65535;j++);                         printf("\ntest_sd\n");//                 } } Add FatFs header files in the main.h. #include "spi.h" #include "SD.h" #include "diskio.h" #include "ff.h" 5 Test result     After download the code to the KL26 board, then insert a 8G microSD card which already format with the Fat32, press the reset button on the board, user can find the following printf log from the com port: It means the SD card is identified.      Now, take out the SD card and insert it to the PC, user will find there has two files: Test.csv and Test.txt. Open these files, data Test1, Test2, Test3, Test4 can be find in it,  it means the FatFs file system is porting successfully.
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Although most of us have a basic understanding of how an ADC works and how to understand some of the basic figures that define an ADC performance, that is far from really understanding how to fully interpret and use the figures depicted in a datasheet ADC section. With all those numbers it is easy to get lost on which ones to look at when we want to know how it will react to conditions such as frequency, signal amplitude, temperature, etc; having such knowledge would allow us to better fit a specific ADC to your application and take full advantage of its features. Having this in mind I took the time to compile some information related to what the most common figures that describe an ADC performance depicted in a datasheet mean, most of the material can be found in any Analog to Digital Conversion theory book; as I mentioned before this is just a general compilation of knowledge I hope will help you better understand those specifications. It assumes those of us who use datasheets are somehow familiar with the basic working of ADCs, so I will spare the basic concepts. Now down to business, this is a extract of a typical ADC section from a microcontroller's datasheet: I am almost certain not a lot of people who use microcontrollers, and more specifically ADCs; have a clear idea of what Total Unadjusted Error, Integral Non-Linearity or Differential Non-Linearity describe in the behavior of an ADC. Even though I will try to describe in detail the most common parameters I might miss some others and there is the possibility some of the information might not be as accurate as I would like it to be, if any of you reading this brief document have specific questions regarding any parameter I describe or miss by all means comment. Common ADC electrical characteristics depicted in datasheets EQ           Quantization error      Since the analog input to an ADC can take any value, but the digital output is quantized, there may be a difference of up to ½ Less Significant Bit between the actual analog input and the exact value of the digital output. This is known as the quantization error or quantization uncertainty as shown below. In ac (sampling) applications this quantization error gives rise to quantization noise. SINAD, SNR and ENOB ( Signal to Noise plus Distortion, SIgnal to Noise Ratio and Effective Number of Bits)      Signal-to-Noise-and Distortion (SINAD, or S/(N + D) is the ratio of the rms signal amplitude to the mean value of the root-sum square (rss) of all other spectral components, including harmonics, but excluding dc. SINAD is a good indication of the overall dynamic performance of an ADC      as a function of input frequency because it includes all components which make up noise (including thermal noise) and distortion. It is often plotted for various input amplitudes. SINAD is equal to THD + N if the bandwidth for the noise measurement is the same. SINAD is often converted      to effective-number-of-bits (ENOB) using the relationship for the theoretical SNR of an ideal N-bit ADC: SNR = 6.02N + 1.76 dB, the equation is solved for N, and the value of SINAD is substituted for SNR.      Effective number of bits (ENOB) is a measure of the dynamic performance of an analog to digital converter and its associated circuitry. The resolution of an ADC is specified by the number of bits used to represent the analog value, in principle giving 2 N signal levels for an N-bit signal. However, all real ADC circuits introduce noise and distortion. ENOB specifies the resolution of an ideal ADC circuit that would have the same resolution as the circuit under consideration. Often ENOB is calculated using the relationship for the theoretical SNR of an ideal N-bit ADC: SNR =      6.02N + 1.76 dB, the equation is solved for N, and the value of SINAD is substituted for SNR. SFDR       Spurious Free Dynamic Range     One of the most significant specification for an ADC used in a communications application is its spurious free dynamic range (SFDR). SFDR of an ADC is defined as the ratio of the rms signal amplitude to the rms value of the peak spurious spectral content measured over the bandwidth      of interest. SFDR is generally plotted as a function of signal amplitude and may be expressed relative to the signal amplitude (dBc) or the ADC full-scale (dBFS) as shown in Figure n. For a signal near full-scale, the peak spectral spur is generally determined by one of the first few harmonics of the fundamental. However, as the signal falls several dB below full-scale, other spurs generally occur which are not direct harmonics of the input signal. This is because of the differential nonlinearity of the ADC transfer function as discussed earlier. Therefore, SFDR      considers all sources of distortion, regardless of their origin. INL       Integral Non-Linearity     Integral nonlinearity (acronym INL) is the maximum deviation between the ideal output of an ADC and the actual output level (after offset and gain errors have been removed). The transfer function of an ADC should ideally be a line and the INL measurement depends on the ideal line selected. Two often used lines are the best fit line, which is the line that minimizes the INL result and the endpoint line which is a line that passes through the points on the transfer function corresponding to the lowest and highest input code. In all cases, the INL is the maximum distance between the ideal line selected and the actual transfer function. DNL         Differential Non-Linearity      Differnetial NonLinearity relates to the linearity of the code transitions of the converter. In the ideal case, a change of 1 LSB in digital code corresponds to a change of exactly 1 LSB of analog signal. In an ADC there should be exactly 1 LSB change of analog input to move from one           digital transition to the next. Differential linearity error is defined as the maximum amount of deviation of any quantum (or LSB change) in the entire transfer function from its ideal size of 1 LSB. Where the change in analog signal corresponding to 1 LSB digital change is more or less than 1 LSB, there is said to be a DNL error. The DNL error of a converter is normally defined as the maximum value of DNL to be found at any transition across the range of the converter. The following figure shows the non-ideal transfer functions for an ADC and shows the effects of the DNL error.      A common result of excess DNL in ADCs is missing codes resulting from DNL < –1 LSB. THD      Total Harmonic Distortion Total harmonic distortion (THD) is the ratio of the rms value of the fundamental signal to the mean value of the root-sum-square of its harmonics (generally, only the first 5 are significant). THD of an ADC is also generally specified with the input signal close to full-scale, the harmonics of the input signal can be distinguished from other distortion by their location in the frequency spectrum. The second and third harmonics are generally the only ones specified on a data sheet because they tend to be the largest. EFS      Full Scale Error Full-scale error can be defined as the difference between the actual value triggering the transition to full-scale and the ideal analog full-scale transition value. Full-scale error is equal to the offset error + gain error Offset error The transfer characteristics of both DACs and ADCs may be expressed as a straight line given by D = K + GA, where D is the digital code, A is the analog signal, and K and G are constants. In a unipolar converter, the ideal value of K is zero. The offset error is the amount by which the actual value of K differs from its ideal value. Gain error The gain error is the amount by which G differs from its ideal value, and is generally expressed as the percentage difference between the two, although it may be defined as the gain error contribution (in mV or LSB) to the total error at full-scale. TUE      Total Unadjusted Error This is the result of performing conversions without having calibrated the ADC, it is dominated by the uncalibrated gain and uncalibrated offset terms in the data sheet. Although most devices will be well within the data sheet limits, it should be noted that they are not centered around zero and full range of the incoming analog signal is not guaranteed. Therefore, an uncalibrated ADC will always show unknown levels of gain and offset error, thus reflecting the worst case of conversion error the module can provide.
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The following document contains a list of documents , questions and discussions that are relevant in the community based on the amount of views they are receiving each month. If you are having a problem, doubt or getting started in Kinetis processors or MCUXpresso, you should check the following links to see if your doubt have been already solved in the following documents and discussions. MCUXpresso MCUXpresso Supported Devices Table FAQ: MCUXpresso Software and Tools  Getting Started with MCUXpresso and FRDM-K64F  Generating a downloadable MCUXpresso SDK v.2 package  Quick Start Guide – Using MCUXpresso SDK with PINs&amp;CLOCKs Config Tools  Moving to MCUXpresso IDE from Kinetis Design Studio Kinetis Microcontrollers Guides and examples Using RTC module on FRDM-KL25Z  Baremetal code examples using FRDM-K64F Using IAR EWARM to program flash configuration field Understanding FlexIO  Kinetis K80 FAQ How To: Secure e-mail client (SMTP + SSL) with KSDK1.3 + WolfSSL for FRDM-K64F  Kinetis Bootloader to Update Multiple Devices in a Network - for Cortex-M0+  PIT- ADC- DMA Example for FRDM-KL25z, FRDM-K64F, TWR-K60D100 and TWR-K70  USB tethering host (RNDIS protocol) implementation for Kinetis - How to use your cellphone to provide internet connectivity for your Freedom Board using KSDK Write / read the internal flash Tracking down Hard Faults  How to create chain of pbuf's to be sent? Send data using UDP.  Kinetis Boot Loader for SREC UART, SD Card and USB-MSD loading  USB VID/PID numbers for small manufacturers and such like  Open SDA and FreeMaster OpenSDAv2  Freedom OpenSDA Firmware Issues Reported on Windows 10 Let´s start with FreeMASTER!  The Kinetis Design Studio IDE (KDS IDE) is no longer being actively developed and is not recommended for new designs. The   MCUXpresso   IDE has now replaced the Kinetis Design Studio IDE as the recommended software development toolchain for NXP’s Kinetis, LPC and i.MX   RT Cortex-M based devices. However, this documents continue to receive considerable amount of views in 2019 which means it could be useful to some people. Kinetis Design Studio New Kinetis Design Studio v3.2.0 available Using Kinetis Design Studio v3.x with Kinetis SDK v2.0  GDB Debugging with Kinetis Design Studio  KDS Debug Configurations (OpenOCD, P&amp;E, Segger) How to use printf() to print string to Console and UART in KDS2.0  Kinetis Design Studio - enabling C++ in KSDK projects  Using MK20DX256xxx7 with KDS and KSDK  Kinetis SDK Kinetis SDK FAQ  Introducing Kinetis SDK v2  How to: install KSDK 2.0  Writing my first KSDK1.2 Application in KDS3.0 - Hello World and Toggle LED with GPIO Interrupt 
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This is a Processor Expert project created by CodeWarrior for MCUs v10.6 which implements the charge-discharge time of a RC circuit for measuring capacitance. The charge-discharge sequence is performed by TPM0 operating in PWM mode, while the time is measured by TPM1 operating in Input Capture mode. A 100K ohm series resistor is being used, and the result is expressed on nF. It is also using the LCDHTA component from Erich Styger for showing the measurements on a 16x2 LCD, connected to the FRDM-KL05Z through a proto shield. The project is attached, and the pictures shows the measurements of three different capacitors: 10nF, 47nF and 1uF.
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Hello All, Power consumption of devices and implications around designing on embedded systems is a common topic nowadays. Kinetis MCUs offer different power modes to fit user's needs. Among these low power modes, we can find the lowest consumption modes: Low-Leakage Stop (LLS) and Very Low-Leakage Stop modes (VLLS). Attached document provides a brief introduction/explanation on these modes and lists the steps needed to configure MCU to operate in any of these modes. It is a bare-board project for FRDM-KL26Z but same principle applies to other Kinetis families. Also, two projects for KDS v3.2 are attached for reference. I hope you can find them useful! Regards, Isaac
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Latest version of the AN2295 universal bootloader includes support for IAR 7.6 IDE. - added support for Kinetis E MCUs - Kinetis K,L,M,E,W,V support
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Introduction The K32L3A60VPJ1AT MCU is a next generation Kinetis dual core device.  This device brings processing and multi-tasking capabilities that legacy Kinetis devices did not support.  In addition, the K32L3A60VPJ1AT offers improved power consumption and security features.   Some important aspects of these security features lie in a nonvolatile information register (IFR) memory region and how this region is programmed.  The IFR memory region is a memory space with restricted access separate from the main array and is comprised of an erasable IFR region and a non-erasable IFR region.  The non-erasable IFR region contains the program once identifier and the version identifier.  The erasable IFR region holds the flash security, flash options, mass erase enable, and other such features that governs how the device behaves.  In legacy Kinetis devices, certain fields of the main flash array (flash addresses 0x400 - 0x40F) configured the IFR at boot time.  In the K32L3A60VPJ1AT however, the IFR memory region is no longer controlled in this manner.  This presents challenges when trying to configure these settings.  The purpose of this document is to explain how these settings can be changed and provide some options of how to make these changes.   The first step in configuring the IFR fields is understanding how the these fields are programmed via the hardware. IFR fields are programmed using a special flash command called the Program Index Command. Once programmed, the flash configuration values cannot be reprogrammed without first erasing these fields.  The only way to erase these values is via a mass erase.  This provides security in that the IFR values cannot be changed without erasing the user code as well.  In addition, changes to the user code image cannot affect the bootloader operation, ensuring that a secure boot function can be executed.  The procedure for writing the erasable IFR values is described here: Write FCCOB0 with the Program Index command (0x43). Write FCCOB1 with the Index to be programmed. The possible Indexes are listed in Erasable IFR Map table (table 16.4.1.2 in the K32L3A6 reference manual). Write FCCOB2 and FCCOB3 with 0x00 as they are not used with this command.  Write FCCOB4 - FCCOBB with the desired value.  (Note that not all of the indexes use all of the FCCOB fields.  Be sure to consult the Erasable IFR Map table for which FCCOB fields are used for the index you are programming).  Write 0x70 to the Flash status register (FSTAT) to clear any errors that might have been present from the last flash command. (Note that this command MUST be a byte write.) Write 0x80 to the Flash status register (FSTAT) to initiate the programmed flash command. Poll the FSTAT register until the CCIF bit field (bit field 7) is one ('1').  (Note that it may not be possible in your scripting language to do this, or it may just be easier to simply wait for the flash command to finish executing. In these cases, wait significantly longer than the typical Program Index command completion time of 110us.) After the IFR has been programmed, the IFR should be read back to verify that it completed correctly.  The process for this is as follows: Write FCCOB0 with the Read Index command (0x41). Write FCCOB1 with the Index to be read.   The possible Indexes are listed in Erasable IFR Map table (table 16.4.1.2 in the K32L3A6 reference manual). Write FCCOB2 - FCCOBB with 0. The results will be stored in FCCOB4 - FCCOBB so, these should be cleared to ensure correct results are received. Write 0x70  to the Flash status register (FSTAT) to clear any errors that might have been present from the last flash command. Note that this command MUST be a byte write. Write 0x80 to the Flash status register (FSTAT) to initiate the programmed flash command . Poll the FSTAT register until the CCIF bit field (bit field 7) is one ('1').  (Note that it may not be possible in your scripting language to do this, or it may just be easier to simply wait for the flash command to finish executing. In these cases, wait significantly longer than the maximum Read Index command completion time of 35us.) When using the Program Index Command, you must know which index you want to modify to create the correct flash commands.  The index list can be found in the IFR descriptions section of the Flash chapter in the K32L3A60VPJ1AT reference manual.   There are several different options for programming the FOPT fields. These options are: Using the Kinetis Flash Tool  Using blhost Debugger script Subroutine in user software Option #1: Kinetis Flash Tool Using the Kinetis Flash Tool is likely the most convenient method to change the IFR values.  The Kinetis Flash Tool uses either the UART or USB protocol to interface with the K32L3A6 bootloader and write the IFR fields desired. One of the biggest advantages for the Kinetis Flash Tool is that it provides a graphical interface for users to easily program the IFR fields. The following figure is a picture of the Kinetis Flash Tool and highlights the important input controls and tabs to be used when programming the IFR fields: This field is the Port set box.  It selects the interface (UART or USB) to be used when communicating to the bootloader.  This box also allows for configuration of the interface.  Consult the K32L3A6 reference manual for default configurations.   This is the Flash Utilities tab.  Select this tab to see the controls shown in this image.  This is the Index input field.  The Index of the IFR to program should be entered here.  This is the Hex digits field.  This value will be programmed at the IFR Index indicated in the Index field. The value here should be in hex format WITHOUT the preceding "0x".   This is the Byte Count field.  This tells the utility how many bytes to program and must be the byte count of that IFR field.  Consult the Erasable IFR Map table in the reference manual for the value of the specific IFR index to be programmed.   This is the Program button.  After all of the fields have been filled out, click this button to program the desired IFR location.  Option #2: BLHOST The MCUBoot package also includes a command line executable to interface with the bootloader.  This tool, blhost, can be used to program the IFR fields as well.  The "flash-program-once" command should be used to program the desired IFR location.  The syntax of this command is as follows: flash-program-once <index> <byteCount> <data> So for example, if you want to program the FOPT IFR field (record index 0x84) with 0xFFFFF3FF, the correct syntax using this command would be flash-program-once 0x84 4 FFFFF3FF After programming, the "flash-read-once" command can be used to read back and verify the programmed IFR field(s).  Below is an example using the previous IFR locations flash-read-once 0x84 4 Below is a full example of erasing the device, programming the FOPT IFR, and reading the FOPT IFR back from the command line using blhost.   Option #3: Debugger Script A simple debugger script is another convenient way to write the IFR values.  Debugger scripts are executed in the background of the debug session initiation process (therefore are hidden operations from the user) and typically can be edited easily using any text editor.  However, it can be cumbersome to change the value because this generally must done manually with each programming by the user. With that in mind, it is a good idea to have different connect scripts for different configurations The first step in using a debugger script is writing a debugger script.  The capabilities and syntax of a debugger script are dependent on your toolchain. For the purposes of this document, we will focus on MCUXpresso IDE.  MCUXpresso IDE uses the PokeXX and PeekXX (where XX is 8, 16, or 32 depending on whether you want to byte access, half-word or word access to the desired register) commands, which are debugger agnostic. So the same commands that work on a device will continue to work whether you are debugging with a JLink or CMSIS-DAP, or whatever other debugger you are using. Below is an example of a MCUXpresso connect script which writes the FOPT register and then reads it back for printing to the debug log.  5140 REM ====================Program FOPT=================================== 5150 Poke32 this 0x40023004 0x43840000 5160 REM Stuff FCCOB registers with desired FOPT value 5170 Poke32 this 0x40023008 v% 5171 s% = Peek32 this 0x40023008 5172 Print "New Val ";~s% 5180 Poke32 this 0x4002300c 0x00000000 5180 Poke8 this 0x40023000 0x70 5190 Poke8 this 0x40023000 0x80 5200 wait 1000 6000 REM ================== Read FOPT ===================================== 6001 REM Now read the FOPT back 6010 Poke32 this 0x40023004 0x41840000 6020 Poke32 this 0x40023008 0x00000000 6030 Poke32 this 0x4002300c 0x00000000 6040 Poke8 this 0x40023000 0x70 6050 Poke8 this 0x40023000 0x80 6060 wait 1000 6070 s% = Peek32 this 0x40023008 6080 Print "New FOPT Val ";~s%   Note in the above script that v% is the desired FOPT value and it has been defined in sections of the script not shown (at line 164).  162 REM This is the value to be written to the FOPT 164 v% = 0xfffff3ff After the script is written, MCUXpresso must be told to use the connect script.  This is done in the Debug Configurations window.  Assuming a debug configuration has already been created, click on the arrow next to the green bug icon and select Debug Configurations.   In the resulting dialog box, select the debug configuration you want to use, and select the Linkserver Debug tab.  In the Connect Script field, point MCUXpresso to the location of your connect script.   That's all that needs to be done in the IDE. The selected debug configuration should now be using the script which was written.   Some debuggers will allow standalone command line running of a script, such as a JLink debugger.  As the JLink is one of the more popular external debuggers that we encounter, an example of programming using this script has been provided below.   // Now Program the FOPT w4 0x40023004, 0x43840000 // The 43 selects the Program Index command. The 84 selects the FOPT IFR field. // Stuff the FCCOB registers (4-7) with the FOPT value we want to write. // ** (Boot Settings) ** w4 0x40023008, 0xfffff3ff // Write 0xFFFF_1FFF to boot the M4 from internal Flash. Asserting the NMI pin will force booting from the ROM. // Write FCCOB registers 8-B with dummy values. w4 0x4002300c, 0x00000000 // Write the FSTAT register to clear any errors that could have been present. w1 0x40023000, 0x70 // Launch the flash command. w1 0x40023000, 0x80 // Wait for the flash command to finish. Sleep 1 // Now Read the FOPT back w4 0x40023004, 0x41840000 // The 43 selects the Program Index command. The 84 selects the FOPT IFR field. // Stuff the FCCOB registers (4-7) with the FOPT value we want to write. // ** (Boot Settings) ** w4 0x40023008, 0x00000000 // Write 0xFFFF_F1FF to boot the M0+ from internal Flash. Asserting the NMI pin will force booting from the ROM. // Write FCCOB registers 8-B with dummy values. w4 0x4002300c, 0x00000000 // Write the FSTAT register to clear any errors that could have been present. w1 0x40023000, 0x70 // Launch the flash command. w1 0x40023000, 0x80 // Wait for the flash command to finish. Sleep 1 // Read the memory back to verify the FOPT settings that should be present after reset. mem32 40023000,4 Option #4: Subroutine in User Software Occasionally the requirements of your system will prevent implementation of any of the above methods to program the IFR values.  In these cases, you may need to implement your own subroutine to program the IFR.  The procedure to do this is essentially the same as in the debugger script methods, just written in code instead of an external script.  One key to remember is that you likely will need to erase the entire flash.  So this subroutine should be placed in RAM memory.  Because flash operations are executing, being in RAM will prevent certain flash errors from occurring.   Conclusion In summary, the IFR registers are nonvolatile information registers that govern certain behaviors of the K32L3A MCU.  The IFR is dividing into an  erasable IFR space and non-erasable IFR space, both of which are not a part of the main flash array.  Programming these values requires the use of special flash commands and requires that these values haven't been previously written since the last mass erase.  There are, in general, four different methods of programming the FOPT register settings.  The four methods are: Kinetis Flash Tool BLhost command line interface Debugger script  User software subroutine Each method has its advantages, therefore, you should pick the one that meets your needs and is most convenient. However with any of the methods chosen, the IFR values must not have been programmed before writing erasable IFR fields. It is best to perform a mass erase (which can be done using any of the methods presented in this document) before attempting to program any IFR fields.     
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Hello all.   I would like to share an example project for FRDM-KL25Z board on which C90TFS Flash Driver was included to implement emulated EEPROM (Kinetis KL25 doesn’t have Flex Memory). It is based on the “NormalDemo” example project. A string of bytes is stored on the last page of the flash memory (address 0x1FC00-0x1FFFF), and then, it is overwritten with a different string.   The ZIP file also includes the “Standard Software Driver for C90TFS/FTFx Flash User’s Manual” document. For more information, please refer to Freescale website and search for “C90TFS” flash driver. Hope this will be useful for you. Best regards! /Carlos
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    以DMA方式通过UART发送数据应该是工程应用中很常用的一种方式了,尤其是在需要频繁发送数据或者数据包长度较大的场合,如果使用传统的UART查询或者中断方式发送和接收数据,对CPU资源的占用将是极大的浪费,带操作系统的应用还好些,如果是纯粹的前后台程序有时不能容忍的,所以DMA方式是很恰当的选择。 而本篇以Kinetis L系列为例介绍一下以DMA方式通过UART端口发送长数据包,当然不同于K系列复杂强大的eDMA功能,L系列的DMA模块配置起来还是比较简单的。 测试平台:IAR6.7 + KL26 FRDM 测试代码:FRDM-KL26Z_SC\FRDM-KL26Z_SC_Rev_1.0\klxx-sc-baremetal\build\iar\uart0_dma        其实KL26的官方sample code中是自带uart0_dma例程的,但是实现的功能只是将UART口接收到的每一个字节的数据通过DMA方式再发送出去(即环形缓冲),这样用来作为一个功能演示的demo是可以,但是往往我们需要的是将某缓冲区的数据以DMA方式发送出去或者将接收到的数据以DMA方式写到某缓冲区这样的功能,为此我们就需要在原有的例程上进行修改从而达到我们的应用目的,这里给出几点需要修改的地方,并做了相关注释(整个工程见最后附件): 1)定义待发送缓冲区: /* array to be sended */ uint8 testdata[]={"\nFreescale Kinetis KL26\n"}; 2)设置DMA源地址: #define DMA0_DESTINATION  0x4006A007    /* the memory adress of UART0_D register */ #define DMA0_SOURCE_ADDR  (uint32)testdata    /* define the source data array address */ 3) 在DMA0_init()函数中修改发送数据包的长度: DMA_SAR0 = DMA0_SOURCE_ADDR;    //Set source address to UART0_D REG DMA_DSR_BCR0 = DMA_DSR_BCR_BCR(sizeof(testdata));    //Set BCR to know how many bytes to transfer DMA_DCR0 &= ~(DMA_DCR_SSIZE_MASK | DMA_DCR_DSIZE_MASK);    //Clear source size and destination size fields 4)添加源地址自动加1功能,因为之前的环形缓冲方式只是单字节数据,所以不需要源地址递增,但是由于我们这次需要发送整个数据包,所以这里我们就需要将源地址递增功能打开,而具体递增1,2还是4则取决于发送数据的最小单位(8bit,16bit or 32bit): /* Set DMA as follows: Source size is 8-bit size Destination size is 8-bit size Cycle steal mode External requests are enabled source address increments 1 automatically */ DMA_DCR0 |= (DMA_DCR_SSIZE(1) | DMA_DCR_DSIZE(1) | DMA_DCR_CS_MASK | DMA_DCR_ERQ_MASK | DMA_DCR_EINT_MASK | DMA_DCR_SINC_MASK ); 5)配置DMAMUX通道为UART0 TX即发送通道(通道号为3),因为我们需要的是UART0_TX触发DMA传送: DMA_DAR0 = DMA0_DESTINATION;    //Set source address to UART0_D REG DMAMUX0_CHCFG0 = DMAMUX_CHCFG_SOURCE(3);    //Select UART0 TX as channel source DMAMUX0_CHCFG0 |= DMAMUX_CHCFG_ENBL_MASK;    //Enable the DMA MUX channel 6)在UART0_DMA_init()函数中修改UART0发送缓冲区为空时即触发DMA发送: void UART0_DMA_init(void) { UART0_C2 &= ~(UART0_C2_TE_MASK | UART0_C2_RE_MASK);  //Disable UART0 UART0_C5 |= UART0_C5_TDMAE_MASK;                      // Turn on DMA request(Transmit) for UART0 UART0_C2 |= (UART0_C2_TE_MASK | UART0_C2_RE_MASK);  //Enable UART0 } 7)在DMA发送完成中断服务函数中禁掉DMA通道,实现单次发送,即每个数据包发送完成之后即停止发送,否则不禁掉的话会一直触发DMA发送,造成串口堵塞: void DMA0_IRQHandler(void) {  /* Create pointer & variable for reading DMA_DSR register */ volatile uint32_t* dma_dsr_bcr0_reg = &DMA_DSR_BCR0; uint32_t dma_dsr_bcr0_val = *dma_dsr_bcr0_reg; if (((dma_dsr_bcr0_val & DMA_DSR_BCR_DONE_MASK) == DMA_DSR_BCR_DONE_MASK)      | ((dma_dsr_bcr0_val & DMA_DSR_BCR_BES_MASK) == DMA_DSR_BCR_BES_MASK)      | ((dma_dsr_bcr0_val & DMA_DSR_BCR_BED_MASK) == DMA_DSR_BCR_BED_MASK)      | ((dma_dsr_bcr0_val & DMA_DSR_BCR_CE_MASK) == DMA_DSR_BCR_CE_MASK)) { DMA_DSR_BCR0 |= DMA_DSR_BCR_DONE_MASK;                //Clear Done bit DMA_DSR_BCR0 = DMA_DSR_BCR_BCR(sizeof(testdata));      //Reset BCR dma0_done = 1; } /* once the array complete the transfer, then disable the DMA channel.*/ DMAMUX0_CHCFG0 &= ~DMAMUX_CHCFG_ENBL_MASK; }        将上述代码做完相应修改即可实现单次将内存缓冲区数据以DMA方式通过UART0发送出去,效果如下。此外,如果想周期性触发或者条件性触发,则只需再相应位置添加“ DMAMUX0_CHCFG0 |= DMAMUX_CHCFG_ENBL_MASK; ”这句代码即可打开通道,然后立即会触发UART0_TX发送数据,然后待数据包发送完之后再次停止等待下次使能。 另外,关于DMA的传输速度的话,因为其独立占用一条自己的总线,其搬运时钟为系统时钟(即coreclock/Systemclock),相比于总线上的传输速度,本例程中整个数据包的发送时间主要是取决于UART串口的波特率*数据包长度。 附件为修改好后的完整工程:
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Introduction With the growth of the Internet of Things (IoT), more and more applications are incorporating the use of sensors while also requiring power efficiency and increased performance.  A popular interface for these sensors is the I2C protocol. The I2C bus is a great protocol that is a true multi-master protocol and allows for each bus to contain many devices.  As the performance demand of the application grows, so will the speed of the I2C bus as it will be necessary to get more data from the sensors and/or at a faster rate.  Many applications may already have a need to operate an I2C bus at 400 kHz or more.  Higher data rates means the MCU core will need to spend more time servicing the I2C transactions.  The DMA module is one good way to free up the core in order to let it tend to other aspects of the application.  This can add much needed or much desired performance to applications.  Especially applications that may be using small, power efficient, single core MCUs. It may seem like an easy, straight-forward task to add I2C reads from a sensor to an application.  However I2C is a time sensitive protocol and consequently, so is the I2C peripherals on MCUs.  It is important to understand the time requirements and how to overcome them. The recommended approach is to use DMA to transfer the received I2C data to the desired buffer in your application software.  This document is going to outline how to setup your DMA and provide an example of how to do this for a KW40 device using the Kinetis SDK version 1.3.  The KW40 is being targeted because this is a small, power efficient MCU that incorporates a radio for your wireless applications and as such, it is likely that your application could need this DMA approach.  The KSDK version 1.3 is being targeted because this version of the SDK does not currently support DMA transactions for the I2C peripheral. Understanding the Kinetis I2C peripheral module Before getting into the specifics of creating a DMA enabled I2C driver, it is important to understand some basics of the Kinetis I2C peripheral module.  This module handles a lot of the low-level timing.  However the I2C registers must be serviced in a timely manner to operate correctly.  Take the case of a master reading data from a typical I2C sensor as shown in the diagram below. In the diagram above, the red lines indicate points in the transaction where software or DMA needs to interact with the I2C peripheral to ensure the transaction happens correctly.  To begin a transaction the core must change the MST bit which puts a start bit on the bus (marked by symbol ST).  Immediately following this, the core should then also write the target slave's address (Device Address) including the read/write bit (R/W).  Once this transaction is complete, the I2C will issue an interrupt and then the core should write the register address to be read from. Upon completion of that being put on the bus, the I2C will issue another interrupt and the master should then put a repeated start (SR) on the bus as well as the slave's address again.  Now the slave will send data to the master (once the master begins the transaction by issuing a dummy read of the I2C data register).  In the standard configuration, the I2C peripheral will automatically send the NAK or AK depending on the configuration of the TXAK bit in the I2C peripheral.  Because of this automation, it is important that this bit be handled properly and is configured one frame in advance. Furthermore, to ensure that the NAK bit is sent at the appropriate time, the TXAK bit must be set when the second to last byte is received.  The timing of this configuration change is very important to ensuring that the transaction happens properly. This document will describe how to use DMA to receive the data.  The DMA will be configured before the transaction begins and will be used to receive the data from the slave.  The document will also discuss options to handle proper NAK'ing of the data to end the transaction. Writing a DMA I2C master receive function The first step in adding DMA capability to your SDK driver is to create a new receive function with an appropriate name.  For this example, the newly created receive function is named I2C_DRV_MasterReceiveDataDMA.  To create this function, the I2C_DRV_MasterReceive function (which is called for both blocking and non-blocking) was copied and then modified by removing the blocking capability of the function. Then in this function, after the dummy read of the IIC data register that triggers the reception of data, the DMA enable bit of the I2C control register is written. /*FUNCTION********************************************************************** * * Function Name : I2C_DRV_MasterReceiveDataDMA * Description   : Performs a non-blocking receive transaction on the I2C bus *                 utilizing DMA to receive the data. * *END**************************************************************************/ i2c_status_t I2C_DRV_MasterReceiveDataDMA(uint32_t instance,                                                const i2c_device_t * device,                                                const uint8_t * cmdBuff,                                                uint32_t cmdSize,                                                uint8_t * rxBuff,                                                uint32_t rxSize,                                                uint32_t timeout_ms) {     assert(instance < I2C_INSTANCE_COUNT);     assert(rxBuff);       I2C_Type * base = g_i2cBase[instance];     i2c_master_state_t * master = (i2c_master_state_t *)g_i2cStatePtr[instance];             /* Return if current instance is used */     OSA_EnterCritical(kCriticalDisableInt);         if (!master->i2cIdle)     {         OSA_ExitCritical(kCriticalDisableInt);         return kStatus_I2C_Busy;     }         master->rxBuff = rxBuff;     master->rxSize = rxSize;     master->txBuff = NULL;     master->txSize = 0;     master->status = kStatus_I2C_Success;     master->i2cIdle = false;     master->isBlocking = true;     OSA_ExitCritical(kCriticalDisableInt);             while(I2C_HAL_GetStatusFlag(base, kI2CBusBusy));     I2C_DRV_MasterSetBaudRate(instance, device);         /* Set direction to send for sending of address. */     I2C_HAL_SetDirMode(base, kI2CSend);       /* Enable i2c interrupt.*/     I2C_HAL_ClearInt(base);     I2C_HAL_SetIntCmd(base, true);       /* Generate start signal. */     I2C_HAL_SendStart(base);       /* Send out slave address. */     I2C_DRV_SendAddress(instance, device, cmdBuff, cmdSize, kI2CReceive, timeout_ms);       /* Start to receive data. */     if (master->status == kStatus_I2C_Success)     {         /* Change direction to receive. */         I2C_HAL_SetDirMode(base, kI2CReceive);                 /* Send NAK if only one byte to read. */         if (rxSize == 0x1U)         {         I2C_HAL_SendNak(base);         }         else         {         I2C_HAL_SendAck(base);         }                 /* Dummy read to trigger receive of next byte in interrupt. */         I2C_HAL_ReadByte(base);                 /* Now set the DMA bit to let the DMA take over the reception. */         I2C_C1_REG(I2C1) |= I2C_C1_DMAEN_MASK;                 /* Don't wait for the transfer to finish. Exit immediately*/     }     else if (master->status == kStatus_I2C_Timeout)     {         /* Disable interrupt. */         I2C_HAL_SetIntCmd(base, false);                 if (I2C_HAL_GetStatusFlag(base, kI2CBusBusy))         {         /* Generate stop signal. */         I2C_HAL_SendStop(base);         }                 /* Indicate I2C bus is idle. */         master->i2cIdle = true;     }         return master->status; } After writing the DMA driver, a DMA specific transfer complete function must be implemented. This is needed in order for the application software to signal to the driver structures that the transfer has been completed and the bus is now idle. In addition, the DMA enable bit needs to be cleared in order for other driver functions to be able to properly use the IIC peripheral. void I2C_DRV_CompleteTransferDMA(uint32_t instance) {     assert(instance < I2C_INSTANCE_COUNT);     I2C_Type * base = g_i2cBase[instance];     i2c_master_state_t * master = (i2c_master_state_t *)g_i2cStatePtr[instance];         I2C_C1_REG(base) &= ~(I2C_C1_DMAEN_MASK | I2C_C1_TX_MASK);     I2C_C1_REG(base) &= ~I2C_C1_MST_MASK;;        /* Indicate I2C bus is idle. */     master->i2cIdle = true; } DMA Configuration Next, the application layer needs a function to configure the DMA properly, and a DMA callback is needed to properly service the DMA interrupt that will be used as well as post a semaphore. But before diving into the specifics of that, it is important to discuss the overall strategy of using the DMA in this particular application. After every transaction, the data register must be serviced to ensure that all of the necessary data is received.  One DMA channel can easily be assigned to service this activity.  After the reception of the second to last data byte, the TXAK bit must be written with a '1' to ensure that the NAK is put on the bus at the appropriate time. This is a little trickier to do.  There are three options: A second dedicated DMA channel can be linked to write the I2C_C1 register every time the I2C_D register is serviced.  This option will require a second array to hold the appropriate values to be written to the I2C_C1 register.  The following figure illustrates this process. The second DMA channel can be linked to write the I2C_C1 register after the second to last data byte has been received.  This option would require that the primary DMA channel be set to receive two data bytes less than the total number of desired data bytes.  The primary DMA channel would also need to be re-configured to receive the last two bytes (or the application software would need to handle this).  However this could be a desirable programming path for applications that are memory constrained as it reduces the amount of memory necessary for your application. The primary DMA channel can be set to receive two data bytes less than the total number of desired data bytes and the core (application software) can handle the reception of the last two bytes.  This would be a desirable option for those looking for a simpler solution but has the drawback that in a system where the core is already handling many other tasks, there may still be issues with writing the TXAK bit on time. This example will focus on option number 1, as this is the simplest, fully automatic solution.  It could also easily be modified to fit the second option as the programmer would simply need to change the number of bytes to receive by the primary DMA and add some reconfiguration information in the interrupt to service the primary DMA channel. DMA Channel #1 The first DMA channel is configured to perform 8-bit  transfers from the I2C data register (I2C_D) to the buffer to hold the desired data.  This channel should transfer the number of desired bytes minus one.  The final byte will be received by the core.  Other DMA configuration bits that are important to set are the cycle steal bit, disable request bit, peripheral request bit (ERQ), interrupt on completion of transfer (EINT), and destination increment (DINC).  It also important to configure the link channel control to perform a link to channel LCH1 after each cycle-steal transfer and LCH1 should be configured for the channel that will transfer from memory to the I2C control register (I2C_C1).  The first DMA channel is configured as shown below. // Set Source Address (this is the UART0_D register       DMA_SAR0 = (uint32_t)&I2C_D_REG(base);             // Set BCR to know how many bytes to transfer       // Need to set to desired size minus 1 because the last will be manually       // read.        DMA_DSR_BCR0 = DMA_DSR_BCR_BCR(destArraySize - 1);             // Clear Source size and Destination size fields.        DMA_DCR0 &= ~(DMA_DCR_SSIZE_MASK                     | DMA_DCR_DSIZE_MASK                     );       // Set DMA as follows:       //     Source size is byte size       //     Destination size is byte size       //     D_REQ cleared automatically by hardware       //     Destination address will be incremented after each transfer       //     Cycle Steal mode       //     External Requests are enabled       //     Interrupts are enabled       //     Asynchronous DMA requests are enabled.       //     Linking to channel LCH1 after each cycle steal transfer       //     Set LCH1 to DMA CH 1.        DMA_DCR0 |= (DMA_DCR_SSIZE(1)             // 1 = 8-bit transfers                    | DMA_DCR_DSIZE(1)           // 1 = 8-bit transfers                    | DMA_DCR_D_REQ_MASK                    | DMA_DCR_DINC_MASK                    | DMA_DCR_CS_MASK                    | DMA_DCR_ERQ_MASK                    | DMA_DCR_EINT_MASK                    | DMA_DCR_EADREQ_MASK                    | DMA_DCR_LINKCC(2)          // Link to LCH1 after each cycle-steal transfer                    | DMA_DCR_LCH1(1)            // Link to DMA CH1                    );       // Set destination address       DMA_DAR0 = (uint32_t)destArray; DMA Channel #2 The second DMA channel, which is the linked channel, should be configured to perform 8-bit transfers that transfer data from an array in memory (titled ack_nak_array in this example) to the I2C control register (I2C_C1).  This channel should also disables requests upon completion of the entire transfer, and enable the cycle-steal mode.  In this channel, the source should be incremented (as opposed to the destination as in the first channel). This channel is configured as shown below: // Set Source Address (this is the UART0_D register       DMA_SAR1 = (uint32_t)ack_nak_array;             // Set BCR to know how many bytes to transfer       // Need to set to desired size minus 1 because the last will be manually       // read.       DMA_DSR_BCR1 = DMA_DSR_BCR_BCR(destArraySize - 1);             // Clear Source size and Destination size fields.        DMA_DCR1 &= ~(DMA_DCR_SSIZE_MASK                     | DMA_DCR_DSIZE_MASK                     );             // Set DMA as follows:       //     Source size is byte size       //     Destination size is byte size       //     D_REQ cleared automatically by hardware       //     Destination address will be incremented after each transfer       //     Cycle Steal mode       //     External Requests are disabled       //     Asynchronous DMA requests are enabled.       DMA_DCR1 |= (DMA_DCR_SSIZE(1)             // 1 = 8-bit transfers                    | DMA_DCR_DSIZE(1)           // 1 = 8-bit transfers                    | DMA_DCR_D_REQ_MASK                    | DMA_DCR_SINC_MASK                    | DMA_DCR_CS_MASK                    | DMA_DCR_EADREQ_MASK                    );             // Set destination address       DMA_DAR1 = (uint32_t)&I2C_C1_REG(base); Once the DMA channels are initialized, the only action left is to configure the interrupts, enable the channel in the DMA MUX, and create the semaphore if it has not already been created.  This is done as shown below. //Need to enable the DMA IRQ       NVIC_EnableIRQ(DMA0_IRQn);       //////////////////////////////////////////////////////////////////////////       // MUX configuration       // Enables the DMA channel and select the DMA Channel Source        DMAMUX0_CHCFG0 = DMAMUX_CHCFG_SOURCE(BOARD_I2C_DMAMUX_CHN); //DMAMUX_CHCFG_ENBL_MASK|DMAMUX_CHCFG_SOURCE(0x31); //0xb1;       DMAMUX0_CHCFG0 |= DMAMUX_CHCFG_ENBL_MASK;             /* Create semaphore */       if(semDmaReady == NULL){         semDmaReady = OSA_EXT_SemaphoreCreate(0);       } Finally, the DMA initialization function also initializes the ack_nak_array.  This is only necessary when implementing the first DMA strategy.  The second DMA strategy would only need to write a single value at the correct time.  The array initialization for strategy #1 is shown below.  Note that the values written to the array are 0xA1 plus the appropriate value of the TXAK bit.  By writing 0xA1, it is ensured that the I2C module will be enabled in master mode with the DMA enable bit set. // Initialize Ack/Nak array       // Need to initialize the Ack/Nak buffer first       for( j=0; j < destArraySize; j++)       {           if(j >= (destArraySize - 2))           {               ack_nak_array[j] = 0xA1 | I2C_C1_TXAK_MASK;           }           else           {               ack_nak_array[j] = 0xA1 & (~I2C_C1_TXAK_MASK);           }       } DMA Interrupt Handler Now a DMA interrupt handler is required.  A minimum of overhead will be required for this example as the interrupt handler simply needs to service the DONE bit and post the semaphore created in the initialization.  The DMA interrupt handler is as follows: void DMA0_IRQHandler(void) {     // Clear pending errors or the done bit     if (((DMA_DSR_BCR0 & DMA_DSR_BCR_DONE_MASK) == DMA_DSR_BCR_DONE_MASK)         | ((DMA_DSR_BCR0 & DMA_DSR_BCR_BES_MASK) == DMA_DSR_BCR_BES_MASK)         | ((DMA_DSR_BCR0 & DMA_DSR_BCR_BED_MASK) == DMA_DSR_BCR_BED_MASK)         | ((DMA_DSR_BCR0 & DMA_DSR_BCR_CE_MASK) == DMA_DSR_BCR_CE_MASK))     {         // Clear the Done MASK and set semaphore, dmaDone         DMA_DSR_BCR0 |= DMA_DSR_BCR_DONE_MASK;         //dmaDone = 1;         OSA_SemaphorePost(semDmaReady);     } } Using your newly written driver function Once all of these items have been taken care of, it is now time for the application to use the functions. It is expected that the DMA will be initialized before calling the DMA receive function.  After the first call, the DMA can be re-initialized every time or could simply be reset with the start address of the arrays and byte counter (this is the minimum of actions that must be performed).  Then the application should ensure that the transaction happened successfully.   Upon a successful call to the I2C_DRV_MasterReceiveDataDMA function, the application should wait for the semaphore to be posted.  Once the semaphore posts, the application software should wait for the Transfer Complete flag to become set.  This ensures that the application does not try to put a STOP signal on the bus before the NAK has been physically put on the bus.  If the STOP signal is attempted out of sequence, the I2C module could be put in an erroneous state and the STOP signal may not be sent.  Next, the I2C_DRV_CompleteTransferDMA function should be called to send the STOP signal and to signal to the driver structures that the bus is idle.  At this point, the I2C transaction is now fully complete and there is still one data byte that hasn't been transferred to the receive buffer.  It is the application's responsibility to perform one last read of the Data register to receive the last data byte of the transaction. /* Now initialize the DMA */    dma_init(BOARD_I2C_INSTANCE, Buffer, ack_nak_buffer, FXOS8700CQ_READ_LEN); //Init DMAMUX       returnValue = I2C_DRV_MasterReceiveDataDMA(BOARD_I2C_INSTANCE, &slave,                                                   cmdBuff, 1, Buffer, FXOS8700CQ_READ_LEN, 1000); if (returnValue != kStatus_I2C_Success)    {        return (kStatus_I2C_Fail);    } /* Wait for the DMA transaction to complete */    OSA_SemaphoreWait(semDmaReady, OSA_WAIT_FOREVER);       /* Need to wait for the transfer to complete */ for(temp=0; temp<250; temp++)     {         if(I2C_HAL_GetStatusFlag(base, kI2CTransferComplete))         {             break;         }     }       /* Now complete the transfer; this includes sending the I2C STOP signal and       clearing the DMA enable bit */    I2C_DRV_CompleteTransferDMA(BOARD_I2C_INSTANCE);       // Once the Transfer is complete, there is still one byte sitting in the Data    // register.      Buffer[11] = I2C_D_REG(g_i2cBase[BOARD_I2C_INSTANCE]); Conclusion To summarize, as consumers demand more and more power efficient technology with more and more functionality, MCU product developers need to cram more functionality in small power efficient MCUs.  Relying on DMA for basic data transfers is one good way to improve performance of smaller power efficient MCUs with a single core. This can be particularly useful in applications where an MCU needs to pull information from and I2C sensor.  To do this, there are three methods of implementing an I2C master receive function in your SDK 1.3 based application. Use two DMA channels.  The first to transfer from the I2C Data register to the destination array.  A second dedicated DMA channel can be linked to write the I2C_C1 register every time the I2C_D register is serviced. Use two DMA channels.  The first to transfer from the I2C Data register to the destination array. The second DMA channel can be linked to write the I2C_C1 register only after the second to last data byte has been received. Use a single DMA channel can be set to receive two data bytes less than the total number of desired data bytes and the core (application software) can handle the reception of the last two bytes. The recommendation of this document is to implement the first or second option as these are fully automatic options requiring the least intervention by the core.
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The FRDM-KL25Z is an ultra-low-cost development platform enabled by Kinetis L Series KL1 and KL2 MCUs families built on ARM® Cortex™-M0+ processor. Features include easy access to MCU I/O, battery-ready, low-power operation, a standard-based form factor with expansion board options and a built-in debug interface for flash programming and run-control. The FRDM-KL25Z is supported by a range of Freescale and third-party development software. Features MKL25Z128VLK4 MCU – 48 MHz, 128 KB flash, 16 KB SRAM, USB OTG (FS), 80LQFP Capacitive touch “slider,” MMA8451Q accelerometer, tri-color LED Easy access to MCU I/O Sophisticated OpenSDA debug interface Mass storage device flash programming interface (default) – no tool installation required to evaluate demo apps P&E Multilink interface provides run-control debugging and compatibility with IDE tools Open-source data logging application provides an example for customer, partner and enthusiast development on the OpenSDA circuit Take a look at these application notes: USB DFU boot loader for MCUs Developer’s Serial Bootloader. Low Cost Universal Motor Drive Using Kinetis L family . Writing your First MQXLite Application Learn more...
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