Our pressure sensors are designed to be used with clean, dry air only. However, most of our customers ran their own tests to determine if the response of the sensor would be appropriated for their specific applications. I personally ran a test with an MPXV5700AP directly exposed to car coolant @25°C and 100PSI, zero failure was detected for almost a month. See attached .xlsx for detailed information. The error of the sensor was calculated comparing the output of the sensor with a mechanical manometer, however this was only an approximation since the mechanical manometer was used as the "true pressure value". In this kind of applications, we would recommend to use Parker O-lube silicone grease or DMS-T46 or T51. This type of grease is used by most of our customer without problems. In fact the basic recommendations are to use a silicone oil (or preferably grease) with high viscosity and high molecular weight. In this case the size of the molecules are big enough to limit the penetration of the grease inside our protective silicone gel which is over the die. In terms of contaminants, the silicon grease must be free of halogenures (Cl content < 50 ppm) to reduce the risk of bond pad corrosion. On the other hand, don't forget that whatever the material you will use, as soon as you put something on our gel you have a high probability to see some offset drift. This is coming from additional mechanical stress and/or gel swelling. The amount of gel and global mechanical design are usually also part of the offset drift.

As requested in a prior posting...

My friend Matt Muddiman of Freescale gave this presentation as part of the MEMS Education Series (hosted by Arizona Technology Council and MEMS Industry Group) in Scottsdale Arizona earlier this week.

This time, I would like to share with you an example project using the MPL115A1, the NXP digital barometer.   The MPL115A1 is a simple barometer with digital output for cost-effective applications. It employs a MEMS pressure sensor with a conditioning integrated circuit to provide accurate pressure data. An integrated analog-to-digital converter (ADC) provides digitized temperature and pressure sensor outputs via serial peripheral interface (SPI), with bus speeds up to 8 Mbps.   You may find more information at: MPL115A: 50 to 115kPa, Absolute Digital Pressure Sensor.   I created this project using the FRDM-KL25Z platform and the MPL115A1 absolute digital pressure sensor. The complete source code is written in KDS IDE. You may find the complete project attached to this post.   This document gives you an introduction of the MPL115A1 pressure sensor as well as the different configurations and guides you through the initialization process and how to appreciate the demonstration.   Introduction to the example project This example is based on the application note AN3785 -How to Implement the Freescale MPL115A Digital Barometer. I recommend using it as a reference.   Through this example project, the MCU is configured to use the SPI interface and the PIT module. The local pressure is read every second.   There are MPL115A1 SPI commands to read coefficients, execute Pressure and Temperature conversions, and to read Pressure and Temperature data. The sequence of the commands for the interaction is given as an example to operate the MPL115A1. Initialization of the MKL25Z128 MCU.   Sequence flow chart. The MPL115A1 interfaces to a host (or system) microcontroller in the user’s application. All communications are via SPI. A typical usage sequence is as follows: Every stage of the flow chart is applied on this example and explained below.   Reading coefficient data These are MPL115A2 SPI commands to read coefficients. The coefficients are usually stored in the host microcontoller local memory but can be re-read at any time.   Reading of the coefficients may be executed only once and the values stored in the host microcontroller. It is not necessary to read this multiple times because the coefficients within a device are constant and do not change.   Read Coefficients: [CS=0], [0x88], [0x00], [0x8A], [0x00], [0x8C], [0x00], [0x8E], [0x00], [0x90], [0x00], [0x92], [0x00], [0x94], [0x00], [0x96], [0x00], [0x00], [CS=1] Once the coefficients are obtained, they are computed inside the MPL115A1_Read_Preassure function.     Data conversion This is the MPL115A2 SPI commands to start conversion.   This is the first step that is performed each time a new pressure reading is required which is initiated by the host sending the CONVERT command. The main system circuits are activated (wake) in response to the command and after the conversion completes, the result is placed into the Pressure and Temperature ADC output registers.   Start conversion: [CS=0], [0x24], [0x00], [CS=1], [13 ms Delay]     This is the MPL115A2 SPI commands to read raw temperature and pressure data.     Start Read raw data: [CS=0], [0x80], [0x00], [0x82], [0x00], [0x84], [0x00,] [0x86], [0x00], [0x00], [CS=1]   Compensated pressure reading Once the raw rata is obtained, the compensation procedure is applied as follow:     Local pressure   Once the steps mentioned above are followed, the MPL115A1_Read_Preassure function returns the local pressure value into the local_pressure variable. I recommend evaluating this variable in order to know the final result.     I hope you find the information useful and funny.   Regards, David  

Hi Everyone,   If you are interested in a simple bare metal example code illustrating the use of the accelerometer motion detection function, please find below one of my examples I created for the FXLS8471Q accelerometer while working with the NXP FRDM-KL25Z platform and FRDMSTBC-A8471 board.   The FXLS8471Q is set to detect motion exceeding 315mg for a minimum period of 40 ms on either the X or Y axis. Once an event is triggered, an interrupt will be generated on the INT1 pin:   void FXLS8471Q_Init (void) { FXLS8471Q_WriteRegister(FT_MT_THS_REG, 0x85); // Set threshold to 312.5mg (5 x 62.5mg ) FXLS8471Q_WriteRegister(FF_MT_COUNT_REG, 0x02); // Set debounce timer period to 40ms FXLS8471Q_WriteRegister(FF_MT_CFG_REG, 0xD8); // Latch enabled, motion detection enabled for X and Y axis FXLS8471Q_WriteRegister(CTRL_REG4, 0x04); // Motion interrupt enabled FXLS8471Q_WriteRegister(CTRL_REG5, 0x04); // Route motion interrupt to INT1 - PTD4 FXLS8471Q_WriteRegister(CTRL_REG1, 0x29); // ODR = 12.5Hz, Active mode }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍     In the ISR, only the interrupt flag is cleared and the FF_MT_SRC (0x16) register is read in order to clear the SRC_FFMT flag in the INT_SOURCE register and deassert the INT1 pin, as shown on the screenshot below.   void PORTD_IRQHandler() { PORTD_PCR4 |= PORT_PCR_ISF_MASK; // Clear the interrupt flag IntSource = FXLS8471Q_ReadRegister(FF_MT_SRC_REG); // Read the FF_MT_SRC register to clear the SRC_FFMT flag in the INT_SOURCE register EventCounter++; }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍       Attached you can find the complete source code. If there are any questions regarding this simple example code, please feel free to ask below.    Regards, Tomas

Hello community, As we know, The MMA8451Q has embedded single/double and directional tap detection. This post describes an example project using the Single Tap detection for the MMA8451Q included on the FRDM-KL25Z. Figure 1. Depending on the tapping direction, positive or negative of each axis, the RGB LED will turn into a different color. For more detailed information on how to configure the device for tap detection please refer to NXP application note, AN4072. Configuring the MCU Enable the I2C module of the KL25Z MCU and turn on all the corresponding clocks. In this case, the INT1 output of the MMA8451Q is connected to the PTA14 pin and both SCL and SDA lines are connected to the I2C0 module (PTE24 and PTE25 pins). Please review the FRDM-KL25Z schematic.      //I2C0 module initialization        SIM_SCGC4 |= SIM_SCGC4_I2C0_MASK;        // Turn on clock to I2C0 module        SIM_SCGC5 |= SIM_SCGC5_PORTE_MASK;       // Turn on clock to Port E module        PORTE_PCR24 = PORT_PCR_MUX(5);           // PTE24 pin is I2C0 SCL line        PORTE_PCR25 = PORT_PCR_MUX(5);           // PTE25 pin is I2C0 SDA line        I2C0_F = 0x14;                           // SDA hold time = 2.125us, SCL start hold time = 4.25us, SCL stop hold time = 5.125us *        I2C0_C1 = I2C_C1_IICEN_MASK;             // Enable I2C0 module                   //Configure the PTA14 pin (connected to the INT1 of the MMA8451Q) for falling edge interrupts        SIM_SCGC5 |= SIM_SCGC5_PORTA_MASK;       // Turn on clock to Port A module        PORTA_PCR14 |= (0|PORT_PCR_ISF_MASK|     // Clear the interrupt flag        PORT_PCR_MUX(0x1)|           // PTA14 is configured as GPIO        PORT_PCR_IRQC(0xA));         // PTA14 is configured for falling edge interrupts                   //Enable PORTA interrupt on NVIC        NVIC_ICPR |= 1 << ((INT_PORTA - 16)%32);        NVIC_ISER |= 1 << ((INT_PORTA - 16)%32); Configure the RBG LED of the FRDM-KL25Z Based on FRDM-KL25Z User's Manual , the RGB LED signals are connected as follow: The pins mentioned, are configured as output.      //Configure PTB18, PTB19 and PTD1 as output for the RGB LED        SIM_SCGC5 |= SIM_SCGC5_PORTB_MASK;    // Turn on clock to Port B module        SIM_SCGC5 |= SIM_SCGC5_PORTD_MASK;    // Turn on clock to Port D module                   PORTB_PCR18 |= PORT_PCR_MUX(0x1);     // PTB18 is configured as GPIO        PORTB_PCR19 |= PORT_PCR_MUX(0x1);     // PTB19 is configured as GPIO        PORTD_PCR1 |= PORT_PCR_MUX(0x1);      // PTD1 is configured as GPIO                   GPIOB_PDDR |= (1 << 18);              //Port Data Direction Register (GPIOx_PDDR)        GPIOB_PDDR |= (1 << 19);              //Set GPIO direction set bit corresponding bit on the direction        GPIOD_PDDR |= (1 << 1);               //register for each port, set the bit means OUTPUT Initialize and configure the MMA8451Q for Tap Detection To utilize the single and/or double tap detection the following eight (8) registers must be configured. Register 0x21: PULSE_CFG Pulse Configuration Register Register 0x22: PULSE_SRC Pulse Source Register Register 0x23 - 0x25: PULSE_THSX,Y,Z Pulse Threshold for X, Y and Z Registers Register 0x26: PULSE_TMLT Pulse Time Window 1 Register Register 0x27: PULSE_LTCY Pulse Latency Timer Register Register 0x28: PULSE_WIND Second Pulse Time Window Register Please review the MMA8451Q datasheet in order to get more information about the registers mentioned. For a single tap event, the PULSE_TMLT, PULSE_THSX/Y/Z and PULSE_LTCY registers are key parameters to consider. Note in condition (a) the interrupt is asserted since the acceleration due to a pulse exceeds the specified acceleration threshold (value set in the PULSE_THSX) and crosses up and down before the specified Pulse Time Limit (value set in PULSE_TMLT) expires. Note that in condition (b) the acceleration due to a pulse exceeds the specified acceleration threshold limit, but does not go below the threshold before the specified Pulse Time Limit expires. Therefore, this is an invalid pulse and the interrupt will not be triggered. Also note that the Latency is not shown for this example.              unsigned char reg_val = 0, CTRL_REG1_val = 0;            I2C_WriteRegister(MMA845x_I2C_ADDRESS, CTRL_REG2, 0x40);             // Reset all registers to POR values                 do            // Wait for the RST bit to clear        {               reg_val = I2C_ReadRegister(MMA845x_I2C_ADDRESS, CTRL_REG2) & 0x40;        }      while (reg_val);            I2C_WriteRegister(MMA845x_I2C_ADDRESS, CTRL_REG1, 0x0C);             // ODR = 400Hz, Reduced noise, Standby mode        I2C_WriteRegister(MMA845x_I2C_ADDRESS, XYZ_DATA_CFG_REG, 0x00);      // +/-2g range -> 1g = 16384/4 = 4096 counts        I2C_WriteRegister(MMA845x_I2C_ADDRESS, CTRL_REG2, 0x02);             // High Resolution mode            I2C_WriteRegister(MMA845x_I2C_ADDRESS, PULSE_CFG_REG, 0x15);         //Enable X, Y and Z Single Pulse        I2C_WriteRegister(MMA845x_I2C_ADDRESS, PULSE_THSX_REG, 0x20);        //Set X Threshold to 2.016g        I2C_WriteRegister(MMA845x_I2C_ADDRESS, PULSE_THSY_REG, 0x20);        //Set Y Threshold to 2.016g        I2C_WriteRegister(MMA845x_I2C_ADDRESS, PULSE_THSZ_REG, 0x2A);        //Set Z Threshold to 2.646g        I2C_WriteRegister(MMA845x_I2C_ADDRESS, PULSE_TMLT_REG, 0x28);        //Set Time Limit for Tap Detection to 25 ms        I2C_WriteRegister(MMA845x_I2C_ADDRESS, PULSE_LTCY_REG, 0x28);        //Set Latency Time to 50 ms        I2C_WriteRegister(MMA845x_I2C_ADDRESS, CTRL_REG4, 0x08);             //Pulse detection interrupt enabled        I2C_WriteRegister(MMA845x_I2C_ADDRESS, CTRL_REG5, 0x08);             //Route INT1 to system interrupt            CTRL_REG1_val = I2C_ReadRegister(MMA845x_I2C_ADDRESS, CTRL_REG1);   //Active Mode        CTRL_REG1_val |= 0x01;        I2C_WriteRegister(MMA845x_I2C_ADDRESS, CTRL_REG1, CTRL_REG1_val); Handle the Interrupt The PULSE_SRC register indicates a double or single pulse event has occurred and also which direction. In this case the value of the register mentioned is passed to the PULSE_SRC_val variable and evaluated. Reading the PULSE_SRC register clears all bits. Reading the source register will clear the interrupt.      void PORTA_IRQHandler()      {             PORTA_PCR14 |= PORT_PCR_ISF_MASK;               // Clear the interrupt flag              PULSE_SRC_val = I2C_ReadRegister(MMA845x_I2C_ADDRESS, PULSE_SRC_REG); //Read Pulse Source Register      } Please find attached the complete source code written in the CodeWarrior for Microcontrollers-Eclipse IDE|NXP . As I mentioned before, you can find more detailed information at application note AN4072. Useful information about handling the MMA8451 can be founded in MMA8451Q - Bare metal example project. I hope you find useful and funny this sample project. Regards, David

Hi Everyone, This tutorial is a detailed guide on how to import an ISSDK based example project (e.g. mma845x_interrupt) into MCUXpresso IDE, build and run it on the Freedom board (e.g. FRDM-KL27Z). If you intend to use another ISSDK example project/board, you can always follow this guide. A complete list of MCU boards, sensor kits and sensors supported by ISSDK is available in the ISSDK Release notes. 1. Download the FRDM-KL27Z SDK Open a web browser, navigate to the MCUXpresso homepage and select “Login to view configurations” to start a new configuration. You will be redirected to login to nxp.com. Enter your account information or register for a new account. Back on the MCUXpresso homepage, select the drop-down box to create a New Configuration. Select the board (FRDM-KL27Z) from the list and provide a name for the configuration. Select “Specify Additional Configuration Settings” to choose the Host OS, Toolchain (MCUXpresso IDE) and Middleware (ISSDK). Select Configuration Settings: Host OS (example: Windows) Toolchain/IDE (MCUXpresso IDE) Middleware (ISSDK) Once the configurations are set, select “Go to SDK Builder”.   Select “Request Build” to download the SDK. Once the build request is completed, download the SDK. Agree to Software Terms and Conditions. Unzip SDK to a folder (e.g. SDK_2.2.1_FRDM-KL27Z). 2. Import the SDK_2.1.1_FRDM-KL27Z into MCUXpresso IDE Open MCUXpresso IDE. Set the workspace directory of your choice and click on OK. Switch to the Installed SDKs view within the MCUXpresso IDE window. Open Windows Explorer, and drag and drop the SDK_2.2.1_FRDM-KL27Z (unzipped) file into the installed SDKs view. You will get the following pop-up so click on OK to continue the import.   The installed SDK will appear in the Installed SDKs view. 3. Import and build the ISSDK based mma845x_interrupt example project Find the Quickstart Panel in the lower left hand corner and select Import SDK example(s) Click on the FRDM-KL27Z board and then click on Next. Use the arrow button to expand the issdk_examples category, and then click the checkbox next to mma845x_interrupt to select that project. Then, click on Next. On the next screen, click the checkbox to Redirect printf/scanf to UART so that the terminal output gets sent out the UART instead of using semi-hosting through the debugger. Then click on Finish. Now build the project by clicking on the project name in the Project Explorer view and then click on the Build icon in the Quickstart Panel. You can see the status of the build in the Console view. 4. Run the mma845x_interrupt example project   Now that the project has been compiled, we can flash it to the board and run it. Make sure the FRDM-KL27Z board is plugged in, and click on Debug ‘frdmkl27z_issdk_examples_sensors_mma8451q_mma845x_interrupt’ [Debug] MCUXpresso will probe for connected boards and should find the OpenSDA debug probe that is part of the integrated OpenSDA circuit on the FRDM-KL27Z board. Click on OK to continue. The firmware will be downloaded to the board and the debugger started. Open a Terminal program (e.g. Tera Term) and connect to the FRDM-KL27Z COM port that it enumerated as. Use 115200 baud, 8 data, 1 stop, no parity. Start the application in the MCUXpresso IDE by clicking the "Resume" button. The application is now running and signed 14-bit accelerometer output values are displayed on the terminal. To modify the initial register settings of the MMA8451 accelerometer, find the mma845x_Config_Isr[] structure and change it according to your needs. Well done if you managed to follow along and get it all working. If there are any questions, do not hesitate to ask below. Your feedback or suggestions are also welcome. Regards, Tomas

Hello community, As continuation of the Different pin styles in pressure sensors post, I would like to add some useful information about the pin styles mentioned on the datasheets. Some pressure sensors shows the following pin style configuration: But… What do V1, V2 and VEx actually mean? How should I connect those pins? Answer: V1, V2 and VEX pins are used for factory trimming and it is recommended to leave these pins unconnected. So, in case of unibody package, you will require only pin #1 (Vout), pin #2 (Ground), and pin #3 (Vs) as follow: I hope you find useful this information. Regards, David

Hello Community,   One of the main features of the NXP accelerometers is the Auto-WAKE/SLEEP mode.   I would like to share this project in order to demonstrate the feasibility of using the Low-power and auto-WAKE/SLEEP modes for reducing current consumption in the different NXP accelerometers such as the MMA845x and MMA865x series.   I created this project using the FRDM-KL25Z platform and the MMA8652FC accelerometer (You may find the breakout board files here). The complete source code is written in CodeWarrior v10.x IDE.   This document gives you an introduction of the MMA8652FC accelerometer as well as the different power consumptions and guides you through the initialization process and how to appreciate the demonstration:   Initialization of the MKL25Z128 MCU. Initialization of the MMA8652FC. Auto-WAKE/SLEEP mode. MMA8652FC Embedded functions. Interrupt handlers. Evaluation of the interrupt source. Summarizing the application and Macros definition. Visualization of the current consumption.   1. As you can see in the FRDM-KL25Z schematic and the image below, the I2C signals are routed to the I2C1 module (PTC1 and PTC2 pins) of the KL25Z MCU and the INT1 and INT2 outputs are connected to the PTD5 and PTA5 pins. The INT1 and INT2 outputs of the MMA8652FC are configured as a push-pull active-low outputs, so the corresponding PTD5 and PTA5 pins configuration are GPIOs with an interrupt on falling edge.   The MCU is, therefore, configured as follows:          /* I2C1 module initialization */      SIM_SCGC4 |= SIM_SCGC4_I2C1_MASK;        // Turn on clock to I2C1 module      SIM_SCGC5 |= SIM_SCGC5_PORTC_MASK;       // Turn on clock to Port C module      PORTC_PCR1 |= PORT_PCR_MUX(0x2);         // PTC1 pin is I2C1 SCL line      PORTC_PCR2 |= PORT_PCR_MUX(0x2);         // PTC2 pin is I2C1 SDA line      I2C1_F  |= I2C_F_ICR(0x14);              // SDA hold time = 2.125us, SCL start hold time = 4.25us, SCL stop hold time = 5.125us      I2C1_C1 |= I2C_C1_IICEN_MASK;            // Enable I2C1 module        /*Configure the PTD5 and PTA5 pin (connected to the INT1 and INT2 of the MMA8652FC) for falling edge interrupts */      SIM_SCGC5 |= SIM_SCGC5_PORTD_MASK;       // Turn on clock to Port D module      PORTD_PCR5 |= (0|PORT_PCR_ISF_MASK|      // Clear the interrupt flag                           PORT_PCR_MUX(0x1)|  // PTD5 is configured as GPIO                           PORT_PCR_IRQC(0xA));// PTD5 is configured for falling edge interrupts        SIM_SCGC5 |= SIM_SCGC5_PORTA_MASK;       // Turn on clock to Port A module      PORTA_PCR5 |= (0|PORT_PCR_ISF_MASK|      // Clear the interrupt flag                           PORT_PCR_MUX(0x1)|  // PTA5 is configured as GPIO                           PORT_PCR_IRQC(0xA));// PTA5 is configured for falling edge interrupts        /* Enable PORTD interrupt on NVIC */      NVIC_ICPR |= 1 << ((INT_PORTD - 16)%32);      NVIC_ISER |= 1 << ((INT_PORTD - 16)%32);      /* Enable PORTA interrupt on NVIC */      NVIC_ICPR |= 1 << ((INT_PORTA - 16)%32);      NVIC_ISER |= 1 << ((INT_PORTA - 16)%32);     2. The MMA8652FC is an intelligent, low-power, three-axis, capacitive micromachined accelerometer with 12 bits of resolution.   At the beginning of the initialization, all registers are reset to their default values by setting the RST bit of the CTRL_REG2 register. The Normal and Low Power modes are set in the same register. The MODS[1:0] bits select which Oversampling mode is to be used. The Oversampling modes are available in both WAKE Mode MOD[1:0] and also in the SLEEP Mode SMOD[1:0].   Then the MMA8652FC is initialized as shown below:        I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG2, 0x40);        // Reset all registers to POR values      Pause(0x631);        // ~1ms delay      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, XYZ_DATA_CFG_REG, 0x00); // +/-2g range with ~0.977mg/LSB              /* Power Mode Configuration */      If LOW power mode is selected:      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG2, 0x1B);        // Low Power mode        If NORMAL power mode is selected:      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG2, 0x00);        // Normal mode     3. As I mentioned, one of the main features of the MMA8652FC is the Auto-WAKE/SLEEP mode.   The advantage of using the Auto-WAKE/SLEEP is that the system can automatically transition to a higher sample rate (higher current consumption) when needed, but spends the majority of the time in the SLEEP mode (lower current) when the device does not require higher sampling rates.   • Auto-WAKE refers to the device being triggered by one of the interrupt functions to transition to a higher sample rate. This may also interrupt the processor to transition from a SLEEP mode to a higher power mode. • SLEEP mode occurs after the accelerometer has not detected an interrupt for longer than the user-definable timeout period.       At the ASLP_COUNT register, you can set the minimum time period of inactivity required to switch the part between Wake and Sleep status, in this case, 5 seconds.   The Auto-WAKE/SLEEP mode, therefore, is configured as follow:        read_reg = I2C_ReadRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG2);      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG2, read_reg|0x04);  // Auto-SLEEP enable      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, ASLP_COUNT_REG, 0x10);      // 5 seconds (16 * 320ms)      read_reg = I2C_ReadRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG4);      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG4, read_reg|0x80);  // Enable AutoSleep interrupt, INT2 - PTD5      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG1, 0xC1);           // ODR=800Hz and Sleep mode ODR=1.56Hz, Active mode     4. The device can be configured to generate inertial wake-up interrupt signals from any combination of the configurable embedded functions, enabling the MMA8652FC to monitor inertial events while remaining in a low-power mode during periods of inactivity.   The Interrupts that can WAKE the device from SLEEP are: Tap Detection, Orientation Detection, Motion/Freefall, and Transient Detection.       In this project, the TAP (Pulse) or Transient interrupts are used to wake up the device from the SLEEP. In order to get more information about the TAP detection, please click here.   The MMA8652FC is configured as below:        If Transient interrupt is selected:      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, TRANSIENT_THS_REG, 0x84);         // Set threshold to 252mg (4 x 63mg )      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, TRANSIENT_COUNT_REG, 0x02);       // Set debounce timer period to 40ms (low power mode) / 2.5ms (normal mode)-Table 66      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, TRANSIENT_CFG_REG, 0x17);         // Enable transient detection for X and Y axis, latch enabled         I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG3, 0x40);                 // Wake from Transient interrupt, Push-pull, active low interrupt      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG4, 0x20);                 // Enable Transient detection interrupt      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG5, 0x20);                 // Transient interrupt routed to INT1 - PTA5          If TAP interrupt is selected:      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, PULSE_CFG_REG, 0x15);             // Enable X, Y and Z Single Pulse      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, PULSE_THSX_REG, 0x20);            // Set X Threshold to 2.016g      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, PULSE_THSY_REG, 0x20);            // Set Y Threshold to 2.016g      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, PULSE_THSZ_REG, 0x2A);            // Set Z Threshold to 2.646g      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, PULSE_TMLT_REG, 0x28);            // Set Time Limit for Tap Detection to 25 ms      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, PULSE_LTCY_REG, 0x28);            // Set Latency Time to 50 ms. During this time interval, all pulses are ignored          I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG3, 0x10);                 // Wake from Pulse interrupt, Push-pull, active low interrupt      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG4, 0x08);                 // Pulse detection interrupt enabled      I2C_WriteRegister(MMA8652FC_I2C_ADDRESS, CTRL_REG5, 0x08);                 // Pulse interrupt routed to INT1 - PTA5     5. As I mentioned above, the TAP (Pulse) or Transient interrupts are used to wake up the device from the SLEEP. Besides, if Auto-SLEEP interrupt is enabled, then transitioning from ACTIVE mode to Auto-SLEEP mode (or vice versa) generates an interrupt.   In this project, the Auto-SLEEP, the TAP (Pulse) or the Transient interrupts are enable. The MKL25Z128 responds to these interrupts reading the INT_SOURCE (0x0C) register, in order to determine the appropriate sources of the interrupt.   Every source of interrupt has its own way to clear the interrupt flag. Please refer to the comments of each ISR:        Transient interrupt handler      void PORTA_IRQHandler()      {         PORTA_PCR5 |= PORT_PCR_ISF_MASK;                // Clear the PTC interrupt         int_source = I2C_ReadRegister(MMA8652FC_I2C_ADDRESS, INT_SOURCE_REG); // Clear interrupt Source Register           if(int_source&0x20)  // Transient interrupt ?         {            i = I2C_ReadRegister(MMA8652FC_I2C_ADDRESS, TRANSIENT_SRC_REG); // Read the TRANSIENT_SRC register to clear the SRC_TRANS flag in the INT_SOURCE register             transient_int = 1;         }      }        TAP interrupt handler      void PORTA_IRQHandler()      {         PORTA_PCR5 |= PORT_PCR_ISF_MASK;                // Clear the PTC interrupt flag         int_source = I2C_ReadRegister(MMA8652FC_I2C_ADDRESS, INT_SOURCE_REG); // Clear interrupt Source Register            if(int_source&0x08)  // Pulse interrupt ?         {            i = I2C_ReadRegister(MMA8652FC_I2C_ADDRESS, PULSE_SRC_REG); // Read the PULSE_SRC register to clear the SRC_TRANS flag in the INT_SOURCE register             pulse_int = 1;         }      }        Auto WAKE/SLEEP interrupt handler      void PORTD_IRQHandler()      {          PORTD_PCR5 |= PORT_PCR_ISF_MASK;                // Clear the PTD interrupt flag             int_source = I2C_ReadRegister(MMA8652FC_I2C_ADDRESS, INT_SOURCE_REG); // Clear interrupt Source Register             if (int_source&0x80) // Auto Sleep/Wake interrupt ?          {             i = I2C_ReadRegister(MMA8652FC_I2C_ADDRESS, SYSMOD_REG);      // Read the SYSMOD register to clear the SRC_ASLP flag in the INT_SOURCE register             sleep_int = 1;          }      }     6. At this point, the configuration of the MCU and the accelerometer is done. The RGB LED contained on the FRDM-KL25Z board is configured in order to help showing the behavior of the application. This behavior is configured as follow:        #if TRANSIENT_DETECTION                    if (transient_int){                             transient_int = 0;                 TURN_BLUE_ON(); TURN_RED_OFF();}      #elif TAP_DETECTION                    if (pulse_int){                 pulse_int = 0;                 TURN_BLUE_ON(); TURN_RED_OFF();}      #endif                    if (sleep_int){                  sleep_int = 0;                  TURN_RED_ON(); TURN_BLUE_OFF();}     7. In summary, the FRDM-KL25Z will be interfacing with the MMA8652FC. The power mode will be set and the interrupts will be enabled. The macros at the top of the source code will allow us to select between the different power modes, the different embedded functions and to select the Auto-WAKE/SLEEP function.   If the Auto-WAKE/SLEEP function is enabled, the MMA8652FC will go into the SLEEP mode (ODR=1.56Hz) after 5 seconds of inactivity. The RED LED will be set. When an interrupt from the embedded functions is generated, the MMA8652FC will be awakened (ODR=800Hz) and so on. The BLUE LED will be set.        /* Select the Power Mode - Table 101 from datasheet */      #define NORMAL_MODE        1      #define LOW_POWER_MODE     0         /* Select the Embedded Function */      #define TRANSIENT_DETECTION       1      #define TAP_DETECTION             0        /* Auto-WAKE/SLEEP Function */      #define AUTO_SLEEP   1     8. The Table 5 from the datasheet shows the expected current consumption in regard with the power mode and ODR selected:   As I mentioned before, the Sleep mode allow us to change between different Output Data Rates (ODR) dynamically so we can reduce the current consumption.   In order to verify if the accelerometer is consuming the current mentioned on the datasheet, I measured the MMA8652FC current consumption using the project mentioned.   Please refer to the results below:           9. The advantage of using the Auto-WAKE/SLEEP mode is that the system can automatically transition to a higher sample rate (higher current consumption) when needed, but spends the majority of the time in the SLEEP mode (lower current) when the device does not require higher sampling rates.   In the manner we have come to expect of the MMA8652FC, the current consumption decreases when the ODR is changed from 800Hz to 1.56Hz, in both normal and low power mode.   The information mentioned on the datasheet is now confirmed.     Please find attached the complete source code.   I hope you find useful and funny this sample project. Any suggestion will be appreciated.   You are invited to take part of the NXP community where you can post all your questions and you may find useful material for your projects.   Best Regards, David

I am occasionally asked for the source code for the Android version of our Sensor Fusion Toolbox.  Well, here it is, complete with new NXP graphics and updated links.

************************************************************************************************************* * This simple example code has been written for the NXP FRDM-KL25Z + FRDMSTBC-A8471 * boards and demonstrates how to use the embedded transient detection function * in conjunction with the auto-wake/sleep mode for reducing current consumption * of the FXLS8471Q. * * The transient threshold is set to 312.5mg (5 counts) on the X and Y axis. * Once this threshold is exceeded, the FXLS8471Q is waken up and an interrupt * is generated on the INT1 pin. If the acceleration is below this threshold * within the 1s period, the FXLS8471Q goes back to sleep mode and also * generates an interrupt on the INT1 pin. *************************************************************************************************************

Presented at Sensors Expo, 25 June 2014

Hi, The FXAS2100x, is a small, low-power, yaw, pitch, and roll angular rate gyroscope with 16 bit ADC resolution. The full-scale range is adjustable from ±250°/s to ±2000°/s. It features both I2C and SPI interfaces. Here is a Render of the FXAS2100x Breakout- Board downloaded from OSH Park: Layout Design for this board: In the Attachments section, you can find the Schematic Source File (SCH), Schematic PDF File, Layout Source File (BRD), Gerber Files (GTL, GBL, GTS, GBS, GTO, GBO, GKO, XLN) and BOM files. If you're interested in more designs like this breakout board for other sensors, please go to Freescale Sensors Breakout Boards Designs – HOME

Hi Everyone, I would like to share here one of my examples I created for the MPL3115A2 while working with the NXP FRDM-KL25Z platform and FRDMSTBC-P3115 shield board. It illustrates the use of the embedded FIFO buffer to collect either pressure/temperature or altitude/temperature data that are read from the FIFO using an interrupt technique through the I2C interface. The FIFO is set to store the maximum number of samples (32). Each sample consists of 3 bytes of pressure (or altitude) data and 2 bytes of temperature data. Therefore 160 bytes (32 x (3 + 2)) in total are read from the FIFO when the FIFO is full and the FIFO interrupt is asserted. The MPL3115A2 is initialized as follows. /****************************************************************************** * MPL3115A2 initialization function ****************************************************************************** void MPL3115A2_Init (void) { I2C_WriteRegister(MPL3115A2_I2C_ADDRESS, CTRL_REG1, 0x04); // Reset all registers to POR values Pause(0x631); // ~1ms delay I2C_WriteRegister(MPL3115A2_I2C_ADDRESS, F_SETUP_REG, 0xA0); // FIFO Fill mode, 32 samples I2C_WriteRegister(MPL3115A2_I2C_ADDRESS, CTRL_REG4, 0x40); // Enable FIFO interrupt I2C_WriteRegister(MPL3115A2_I2C_ADDRESS, CTRL_REG5, 0x40); // Route the FIFO interrupt to INT1 - PTA5 I2C_WriteRegister(MPL3115A2_I2C_ADDRESS, CTRL_REG2, 0x00); // Time step = ~1s I2C_WriteRegister(MPL3115A2_I2C_ADDRESS, CTRL_REG3, 0x00); // Push-pull, active low interrupt I2C_WriteRegister(MPL3115A2_I2C_ADDRESS, CTRL_REG1, 0x39); // Active barometer mode, OSR = 128 //I2C_WriteRegister(MPL3115A2_I2C_ADDRESS, CTRL_REG1, 0xB9); // Active altimeter mode, OSR = 128 }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ In the ISR, only the interrupt flag is cleared and the FIFO_DataReady variable is set to indicate that the FIFO is full. /****************************************************************************** * PORT A Interrupt handler ******************************************************************************/ void PORTA_IRQHandler() { PORTA_PCR5 |= PORT_PCR_ISF_MASK; FIFO_DataReady = 1; }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ Once the FIFO_DataReady variable is set, the STATUS register (0x00) is read to clear the FIFO interrupt status bit and deassert the INT1 pin. Afterwars the FIFO is read using a 160-byte (5 x 32 bytes) burst read starting from the OUT_P_MSB register (0x01). Then the raw pressure (or altitude) and temperature data are converted to real values. if (FIFO_DataReady) { FIFO_DataReady = 0; FIFO_Status = I2C_ReadRegister(MPL3115A2_I2C_ADDRESS, STATUS_REG); // Read the Status register to clear the FIFO interrupt status bit I2C_ReadMultiRegisters(MPL3115A2_I2C_ADDRESS, OUT_P_MSB_REG, 5*Watermark_Val, RawData); // Read the FIFO using a burst read for (i = 0; i < Watermark_Val; i++) { /* Get pressure, the 20-bit measurement in Pascals is comprised of an unsigned integer component and a fractional component. The unsigned 18-bit integer component is located in OUT_P_MSB, OUT_P_CSB and bits 7-6 of OUT_P_LSB. The fractional component is located in bits 5-4 of OUT_P_LSB. Bits 3-0 of OUT_P_LSB are not used. */ Pressure[i] = (float) (((RawData[0 + i*5] << 16) | (RawData[1 + i*5] << 8) | (RawData[2 + i*5] & 0xC0)) >> 6) + (float) ((RawData[2 + i*5] & 0x30) >> 4) * 0.25; /* Get temperature, the 12-bit temperature measurement in °C is comprised of a signed integer component and a fractional component. The signed 8-bit integer component is located in OUT_T_MSB. The fractional component is located in bits 7-4 of OUT_T_LSB. Bits 3-0 of OUT_T_LSB are not used. */ Temperature[i] = (float) ((short)((RawData[3 + i*5] << 8) | (RawData[4 + i*5] & 0xF0)) >> 4) * 0.0625; /* Get altitude, the 20-bit measurement in meters is comprised of a signed integer component and a fractional component. The signed 16-bit integer component is located in OUT_P_MSB and OUT_P_CSB. The fraction component is located in bits 7-4 of OUT_P_LSB. Bits 3-0 of OUT_P_LSB are not used */ //Altitude[i] = (float) ((short) ((RawData[0 + i*5] << 8) | RawData[1 + i*5])) + (float) (RawData[2 + i*5] >> 4) * 0.0625; } } ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ Deassertion of the INT1 pin after reading the STATUS register (0x00). The auto acquisition time step is set in this example to the lowest possible value (1s), so the FIFO is read every ~32s. The calculated values can be watched in the "Variables" window on the top right of the Debug perspective. Attached you can find the complete source code. If there are any questions regarding this simple example project, please feel free to ask below. Your feedback or suggestions are also welcome.   Regards, Tomas

SOP Top Side Port Package_1369-01  

MEMS sensors are mechanical structure chips and easily damaged by shock or huge vibration. Sensor package trend is going to small size, and it is not easy to solder by hand on pcb to verify. In order to do sensor verification before FA process, it is necessary to use a tool to load the failed chips and use I2C/SPI to access sensor registers to check sensor function. This document introduces to use sensor fixture and toolbox for a simple sensor verify tool. It is easy to provide precise failed spec items by this tool and to speed-up FA process.

The attached is a copy of a presentation given 24 June 2014 at the Sensors Expo Conference in Rosemont IL.