LPC Microcontrollers Knowledge Base

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LPC Microcontrollers Knowledge Base

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Recently I found some customers have a bit of problem when porting project from one MCU to another, so this article using simple steps demonstrates how to change MCU with MCUXpresso. There is also a video demonstrated the detail steps in attachment. Pay attention, as MCUXpresso User Guide says: All projects are associated with a particular MCU at creation time. The target MCU determines the project memory layout, startup code, LinkServer flash driver, libraries, supporting sources,launch configuration options etc. etc. so changing a project’s associated MCU should not be undertaken unless you have a total grasp of the consequence of this change. Therefore rather than changing a project’s associated MCU, it is strongly recommended that instead a new project is generated for the desired MCU and this new project is edited as required. However, on occasion it may be expedient to reset a project’s MCU (and associated SDK) and this can be achieved as follows. For example, changing lpc55s69 to lpc55s06, we need install SDKs for lpc55s69 and lpc55s06 before all the below steps. 1 - Change MCU & Package 1.1 – Change MCU Right click “MCU” under Project tree, choose “Edit MCU” Uncheck ”Preserve memory configuration”(it is checked by default)->choose LPC55S06->there is a warning, choose Yes. We can see the Memory details changed to lpc55s06, then click ”Apply and close”. 1.2 – Change Package 2 - Change Compiler Definitions In Properties view->Settings->MCU Compiler ->Preprocessor, change the definition for CPU from LPC55S69JBD100 to LPC55S06JBD64 as below: 3 – Change/add SDK driver for LPC55s06 Selected project, then click ”Manage SDK components”, choose the drivers our application used, for example, clock, power, usart. Click “OK”, then click “Yes” to update. Delete LPC55S69 device related files: Add “system_LPC55S06.c” and “system_LPC55S06.h” files: 4 - Change startup file. Delete LPC55s69 startup files, add “startup_lpc55s06.c”, we can find the startup file in any SDK demo. 5 - Change board related files. Refer to our own new board, change files under “board” folder, for example pins, uart number, here directly copy from SDK demo for LPCxpresso55s06 board. 6 - Test the project  function with new board Build project until no compile error, download and run it, result as below.        
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LPC: Regarding to Internal Clock Calibration In MCU development, using the internal crystal oscillator as a clock source instead of the external crystal oscillator can save costs. But the clock frequency generated by the internal crystal oscillator is affected by temperature and MCU frequency more than external crystal oscillator. Many customers have questions about the internal clock accuracy, whether the internal clock can be used for USB transmission, and how to calibrate the internal clock. This article mainly explains this. 1. Calibrate internal clock by FREQTRIM Normally, we can only calibrate the internal clock by adjusting the FREQTRIM value. The internal clock frequency is affected by temperature, MCU frequency and other factors. The FRO control register can calibrate the internal clock, as follows:   The FREQTRIM register value ranges from 0 to 255, and each adjustment step is about 0.1% of the internal clock frequency. There is no precise formula to express the relationship between the FREQTRIM value and the FRO frequency. The ideal FREQTRIM value can only be determined by adjusting FREQTRIM in code and observing FRO output waveform with oscilloscope. Test and observation: The following is the test result. It shows how FRO frequency varies with FREQTRIM increasing from 0-255. Test result of first development board:     Test result of second development board:   The following two points can be seen from test results: - There is no linear relationship between the FRO clock frequency and the FREQTRIM register value, and there is no precise formula to express the relationship between them; - Even for chips of the same part number, the internal clock frequency changes are slightly different, with the FREQTRIM register value changing, but the trend is same. Therefore, there is no precise formula to guide internal clock frequency calibration. You can only adjust the FREQTRIM register value repeatedly, just like adjusting the focus of a projector. Use an oscilloscope to check the frequency of the internal clock pin to find the most suitable FREQTRIM register value. There is same solution for FRO clock frequency calibration about other LPC chips.   2. LPC51U68: Software calibration USB transmission when using internal clock source The Full Speed USB module of LPC51U68 has a unique FRO automatic calibration function, which automatically adjusts the FREQTRIM value to achieve FRO calibration by measuring the USB SOF bit. Once FRO is calibrated, the corresponding system clock and peripheral clock are calibrated. This solution is only applicable to LPC51U68, please refer to the user manual for other chips. The following is the FRO clock accuracy described in LPC51U68 User Manual, which is ± 1%:   For Full Speed USB, the USB data transmission accuracy requirement is ±0.25%, and the FRO clock accuracy is not satisfied. NXP provides a software solution to calibrate FRO by measuring the first packet of frame (SOF), which can meet the transmission accuracy in Full Speed mode.   The solution download link is as follows: https://www.nxp.com/docs/en/application-note/TN00035.zip  
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T his article introduces how to create a custom board MCUXpresso SDK and how to use it, mainly includes three parts: Part1: Generating a Board Support Configuration (.mex) Part2: Create a Custom Board SDK Using the Board SDK Wizard Part3. Using the Custom SDK to Create a New Project   Requirements: MCUXpresso IDE v11.1.1, MCUXpresso SDK for LPC845, LPC845-BRK board. This method works for all NXP mcu which support by MCUXpresso SDK. About detail steps, please refer to attachment. Thanks!
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Hi: Since LPC series ADC has sequence function, so implement multi-channel ADC transfer is easy. But use DMA is also meaning, so there are two demos to show how to use such applications 1.lpc_multi-channels_adc_dma_sw_trg Use SW trigger multi channels ADC transfer, but use DMA to transfer result to result array. use don't need to care the channel result register, but fetch data from global data register; 2.lpc_multi-channels_adc_dma_hw_trg for many cases, user need to trigger ADC multi channels transfer periodly, and collect enough data for processing. so this demo use SCT_OUT7 to trigger ADC Sequence A for 6 channels, then after 1024 rounds, generate DMA interrupt to process all 6*1024 data array. all demos are implemented on SDK2.6.0 
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The documentation discusses how to generate phase-shift PWM signals based on SCTimer/PWM module, the code is developed based on MCUXpresso IDE version 10.3 and LPCXpresso5411x board. The LPC family has SCTimer/PWM module and CTimer modules, both of them can generate PWM signals, but only the SCTimer/PWM module  can generate phase-shift PWM signals. In the code, only the match registers are used to generate events, I/O signals are not used.  The match0 register is set up as (SystemCoreClock/100), which determines the PWM signal frequency. The the match1 register is set up as 0x00, which generate event1. The the match2 register is set up as (SystemCoreClock/100)/2;, which generate event2. The duty cycle is (SystemCoreClock/100)/2-0x00= (SystemCoreClock/100)/2, which is 50% duty cycle, the cycle time is (SystemCoreClock/100). The event1 sets the SCT0_OUT1, event2 clears the SCT0_OUT1, so SCT0_OUT1 has 50% duty cycle. The the match3 register is set up as (SystemCoreClock/100)/4;, which generate even3. The the match4 register is set up as 3*(SystemCoreClock/100)/4, which generate event4. The duty cycle is 3*(SystemCoreClock/100)/4  -  (SystemCoreClock/100)/4= (SystemCoreClock/100)/2, which is 50% duty cycle. The event3 sets the SCT0_OUT2, event4 clears the SCT0_OUT2, so SCT0_OUT2 has 50% duty cycle. The phase shift is (SystemCoreClock/100)/4 - 0x00= (SystemCoreClock/100)/4, which corresponds 90 degree phase shift. PWM initilization code: //The SCT0_OUT1 can output PWM signal with 50 duty cycle from PIO0_8 pin //The SCT_OUT2 can output PWM signal with 50 duty cycle fron PIO0_9 pin //The SCT0_OUT1 and SCT0_OUT2 PWM signal has 90 degree phase shift. void SCT0_PWM(void) {     SYSCON->AHBCLKCTRL[1]|=(1<<2); //SET SCT0 bit     SCT0->CONFIG = (1 << 0) | (1 << 17); // unified 32-bit timer, auto limit     SCT0->SCTMATCHREL[0] = SystemCoreClock/100; // match 0 @ 100 Hz = 10 msec     SCT0->EVENT[0].STATE = 0xFFFFFFFF; // event 0 happens in all states     //set event1     SCT0->SCTMATCHREL[1]=0x00;     SCT0->EVENT[1].STATE = 0xFFFFFFFF; // event 1 happens in all states     SCT0->EVENT[1].CTRL = (1 << 12)|(1<<0); // match 1 condition only     //set event2     SCT0->SCTMATCHREL[2]=(SystemCoreClock/100)/2;     SCT0->EVENT[2].STATE = 0xFFFFFFFF; // event 2 happens in all states     SCT0->EVENT[2].CTRL = (1 << 12)|(2<<0); // match 2 condition only     //set event3     SCT0->SCTMATCHREL[3]=(SystemCoreClock/100)/4;     SCT0->EVENT[3].STATE = 0xFFFFFFFF; // event 3 happens in all states     SCT0->EVENT[3].CTRL = (1 << 12)|(3<<0); // match 3 condition only     //set event4     SCT0->SCTMATCHREL[4]=3*(SystemCoreClock/100)/4;     SCT0->EVENT[4].STATE = 0xFFFFFFFF; // event 4 happens in all states     SCT0->EVENT[4].CTRL = (1 << 12)|(4<<0); // match 4 condition only     //PWM output1 signal     SCT0->OUT[1].SET = (1 << 1); // event 1 will set SCT1_OUT0     SCT0->OUT[1].CLR = (1 << 2); // event 2 will clear SCT1_OUT0     SCT0->RES |= (3 << 2); // output 0 toggles on conflict     //PWM output2 signal     SCT0->OUT[2].SET = (1 << 3); // event 3 will set SCT1_OUT0     SCT0->OUT[2].CLR = (1 << 4); // event 4 will clear SCT1_OUT0     SCT0->RES = (3 << 4); // output 0 toggles on conflict     //PWM start     SCT0->CTRL &= ~(1 << 2); // unhalt by clearing bit 2 of the CTRL } Pin initialization code: //PIO0_8 PIO0_8 FC2_RXD_SDA_MOSI SCT0_OUT1 CTIMER0_MAT3 //PIO0_9 PIO0_9 FC2_TXD_SCL_MISO SCT0_OUT2 CTIMER3_CAP0 - FC3_CTS_SDA_SSEL0 void SCTimerPinInit(void) {     //Enable the     SCTimer clock     SYSCON->AHBCLKCTRL[0]|=(1<<13); //set IOCON bit     //SCTimer pin assignment     IOCON->PIO[0][8]=0x182;     IOCON->PIO[0][9]=0x182;     IOCON->PIO[0][10]=0x182; } Main Code: #include <stdio.h> #include "board.h" #include "peripherals.h" #include "pin_mux.h" #include "clock_config.h" #include "LPC54114_cm4.h" void SCT0_Init(void); void SCTimerPinInit(void); void P1_9_GPIO(void); void SCT0_PWM(void); int main(void) {       /* Init board hardware. */     BOARD_InitBootPins();     BOARD_InitBootClocks();     BOARD_InitBootPeripherals();     printf("Hello World\n");    // SCT0_Init();    // P1_9_GPIO();     SCTimerPinInit();     SCT0_PWM();     /* Force the counter to be placed into memory. */     volatile static int i = 0 ;     /* Enter an infinite loop, just incrementing a counter. */     while(1) {         i++ ;     }     return 0 ; } The Yellow channel is PIO0_8 pin output signal, which is SCT0_OUT1 PWM output signal. The Bule channel is PIO0_9 pin output signal, which is SCT0_OUT2 PWM output signal.
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