MSP430G2553 I2C SCLK 波型異常

user6529956

Prodigy 80 points

Other Parts Discussed in Thread: MSP430G2553, FDC2212

各位前輩與先進您好，

目前使用MSP430G2553來進行I2C通訊，

程式代碼:

if ( TI_USCI_I2C_slave_present(0x2a) ) ;// 這行回傳值為"1"

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_transmitinit(0x2a,ISPEED);

array[0] = 0x08; array[1]=0x12; array[2]= 0x34; // RCOUNT = ffff

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_transmit(3,array); // transmit the first three bytes from array

其中黃色為SCLK，藍色為SDA，下圖為示波器上看到的值。

可以看到一開始為高電位，但是結束後卻沒有拉回到高電位。

還請各位先進與高手幫忙解答，感謝

4 年多前

0 Susan Yang 4 年多前

TI__Guru**** 252096 points

请问您现在从设备是什么？建议您根据从设备I2C的时序要求，增加驱动程序里等待响应的时间试试。

另外网络上有一些比较好的故障分析，您也可以先看一下

www.jianshu.com/.../95f53ca2724e

0 user6529956 4 年多前回复 Susan Yang

Prodigy 80 points

Susan 您好，

MSP43-G2553 (EXP430G2) with the FDC2212(Captative to digital IC).

BCSCTL1 = CALBC1_8MHZ; //

DCOCTL = CALDCO_8MHZ; //

array[0] = 0x08; array[1]=0xff; array[2]= 0xff; // RCOUNT = ffff

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_transmitinit(0x2a,ISPEED);

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_transmit(3,array); // transmit the first three bytes from array

++ 傳遞之後，波型如下:

i2C 外掛 10k 歐姆，有pull high.

想要跟您請教:

1. 如何通常pull high電阻會用多少?

2. 如何增加延遲時間以利i2c能夠順利傳送資料(避免佔線問題)

謝謝您

lin

0 Susan Yang 4 年多前回复 user6529956

TI__Guru**** 252096 points

user6529956 说：
1. 如何通常pull high電阻會用多少?

一般使用的是10K

例程的话，您可以参考链接中的一系列I2C例程

对于 FDC2212，我们也有一个专门的文档，您可以看一下

另外请您以附件形式上传一下图片，谢谢

0 user6529956 4 年多前回复 Susan Yang

Prodigy 80 points

Dear Susan,

非常感謝您的迅速回復，我已經有參考過FDC2212的文件。

至於圖形有兩個疑問:

1. 為何傳完資料後，SDA與SCLK並沒有拉高準位? (資料內容請參考我前一封提問)

2. 為何資料看起來跟我要傳的，完全對不起來?

拜託Susan指導

0 user6529956 4 年多前回复 user6529956

Prodigy 80 points

Dear Susan,

需要您的特別幫忙，

我參考TI_USCI_I2C_master.c 檔案

//------------------------------------------------------------------------------
// void TI_USCI_I2C_transmit(unsigned char byteCount, unsigned char *field)
//
// This function is used to start an I2C communication in master-transmit mode.
//
// IN: unsigned char byteCount => number of bytes that should be transmitted
// unsigned char *field => array variable. Its content will be sent.
//------------------------------------------------------------------------------
void TI_USCI_I2C_transmit(unsigned char byteCount, unsigned char *field){
TI_transmit_field = field;
byteCtr = byteCount;
UCB0CTL1 |= UCTR + UCTXSTT; // I2C TX, start condition
}

並在主程式中，欲傳遞以下資料
array[0] = 0x08; array[1]=0xff; array[2]= 0xff; // RCOUNT = ffff
while ( TI_USCI_I2C_notready() ); // wait for bus to be free
TI_USCI_I2C_transmit(3,array);

但是用示波器去看，總是有問題(SCLK 看起來都會掉Clock，SDA資料看起也不對)
，可以拜託您幫忙看一下程式碼有無問題嗎?

感謝~

0 Susan Yang 4 年多前回复 user6529956

TI__Guru**** 252096 points

若是可以的话，请您私信/上传一下您的完整代码，谢谢

0 user6529956 4 年多前回复 Susan Yang

Prodigy 80 points

全屏 6138.main.c 下载

/*** USCI master library ************************************************************

In this file the usage of the USCI I2C master library without DMA support is
shown. This library uses pointers to specify what data is to be sent.

When calling the TI_USCI_I2C_receive or TI_USCI_I2C_transmit routines
the number of bytes, which are to be transmitted or received have to be passed as
well as a pointer to a data field, that contains(or stores) the data.

This code checks if there is a slave with address 0x50 is connected to the I2C
bus and if the slave device is present, bytes are received and transmitted.

Uli Kretzschmar
MSP430 Systems
Freising

Added FDC2212-Q1 code for TIDA-01409 Capacitive Kick-to-Open Reference Design

*******************************************************************************/
#include "msp430g2553.h"
#include "TI_USCI_I2C_master.h"

#define DATA_CH0_MSB_REG 0x00
#define DATA_CH0_LSB_REG 0x01
#define DATA_CH1_MSB_REG 0x02
#define DATA_CH1_LSB_REG 0x03
///#define ISPEED 0x3F
#define ISPEED 63
//#define ISPEED 12
#define MARGIN 500

signed char byteCtr;
signed char Alive=0;
unsigned char *TI_receive_field;
unsigned char *TI_transmit_field;

unsigned char timercounter;
unsigned char array[3] = {0x00, 0x00, 0x00 };
unsigned char store[10] = { 0xff, 0xff };
unsigned char LSB_Channel_0[2] = { 0x0, 0x0};
unsigned char MSB_Channel_0[2] = { 0x0, 0x1};
unsigned char LSB_Channel_1[2] = { 0x0, 0x2};
unsigned char MSB_Channel_1[2] = { 0x0, 0x3};
unsigned char MUX_CNFG[2] = {0x00,0x00};
unsigned char RCOUNT_0[2] = {'R','0'};
unsigned char RCOUNT_1[2] = {'R','1'};
unsigned char SCOUNT_0[2] = {'S','0'};
unsigned char SCOUNT_1[2] = {'S','0'};
unsigned char IDRIVE_0[3] = {0x1E,0x78,0x00};
unsigned char IDRIVE_1[3] = {0x1F,0x78,0x00};
unsigned char CK_DIV_0[2] = {'C','D'};
unsigned char CK_DIV_1[2] = {'c','d'};
unsigned char ERR_CNFG[2] = {'E','C'};
unsigned char CONFIG[2]   = {'C','F'};
unsigned short DataChannel_0_MSB ;
unsigned short DataChannel_0_LSB ;
unsigned long  DataChannel_0 ;
unsigned short DataChannel_1_MSB=0 ;
unsigned short DataChannel_1_LSB=0;
unsigned long  DataChannel_1 ;
unsigned long Measurement1;
unsigned long Measurement2;
unsigned long Measurement3;


void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WatchDogTimer

  // Set up the GPIO pins for the TIDA-01409 board

  P1DIR |= BIT1;                            // P1.1 is an output (unused pin)

  P1DIR |= BIT4;                            // P1.4 is an output (Shutdown) -> FDC2212 Pin6 SD
  P1OUT &= ~BIT4;                           // Set P1.4 low so Shutdown is LOW

  P1DIR |= BIT2;                            // P1.2 is an output (ADDR)
  P1OUT &= ~BIT2;                           // Set P1.2 low so ADDR is LOW and FDC2212 address is 0x2a, -> FDC2212 Pin4 ADDR
//  P1OUT |= BIT2;                          // Set P1.2 high so ADDR is HIGH and FDC2212 address is 0x2b
  P2DIR |= BIT1;                            // Set P2.1 as an output, Green Led
  P2DIR |= BIT2;                            // Set P2.2 as an output, Red Led

//  P2DIR |= BIT5;                            // Set P2.5 as an output,
//  P2OUT |= BIT5;                            // Set P2.5 high to pull up SDA and SCL
  BCSCTL1 = CALBC1_8MHZ;                    //
  DCOCTL = CALDCO_8MHZ;                     //
//  BCSCTL1 = CALBC1_1MHZ;                    //
//  DCOCTL = CALDCO_1MHZ;                     //

  _EINT();                                  // Enable interrupts

  //    Prepare to write to the FDC2212-Q1 registers
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);  // init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz

  Alive=TI_USCI_I2C_slave_present(0x2a);

  //    Write to the RCOUNT registers for Channel 0 and Channel 1
  array[0] = 0x08;  array[1]=0xff;    array[2]= 0xff;     // RCOUNT = ffff
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array
  __delay_cycles(2000);

  array[0] = 0x09; array[1]=0xff;    array[2]= 0xff;     // RCOUNT = ffff, register address for RCOUNT_CH1
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array, consisting of the register address plus two data bytes
  __delay_cycles(2000);
  //    Write to the ERROR_CONFIG register
  array[0] = 0x19;  array[1]=0x00;    array[2]= 0x01;     // disable all the error reports, enable the data flag interr
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array
  __delay_cycles(2000);
  //    Write to the SETTLECOUNT registers
  array[0] = 0x10;  array[1]=0x00;    array[2]= 0x0A;     // SETTLECOUNT = 000A
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array
  __delay_cycles(2000);
  array[0] = 0x11;   array[1]=0x00;    array[2]= 0x0A;     // SETTLECOUNT = 000A, register address for SETTLECOUNT_CH1
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array (register address plus two data bytes)
  __delay_cycles(2000);

  //    Write to the CLOCK_DIVIDERS registers
  array[0] = 0x14;  array[1]=0x20;    array[2]= 0x01;     // CLOCK_DIVIDERS FIN_SEL=2, FREF_DIVIDER=1
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array
  __delay_cycles(2000);

  array[0] = 0x15; array[1]=0x20;    array[2]= 0x01;     // CLOCK_DIVIDERS FIN_SEL=2, FREF_DIVIDER=1,register address for CLOCK_DIVIDERS_CH1
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array (register address plus two data bytes)
  __delay_cycles(2000);

  //    Write to the DRIVE_CURRENT registers
  array[0] = 0x1E;  array[1]=0x78;    array[2]= 0x00;     // see current drive table p.36 of FDC2212-Q1 datasheet
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,IDRIVE_0);     // transmit the first three bytes from array
  __delay_cycles(2000);
  array[0] = 0x1F; array[1]=0x78;    array[2]= 0x00;    // register address for DRIVE_CURRENT_CH1
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,IDRIVE_1);     // transmit the first three bytes from array (register address plus two data bytes)
  __delay_cycles(2000);

  //    Write to the MUX_CONFIG register
  array[0] = 0x1B;  array[1]=0x82;    array[2]= 0x0D;     // see p.35 of FDC2212-Q1 datasheet
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array
  __delay_cycles(2000);

  //    Write to the CONFIG register    // Last of the set-up write commands
  array[0] = 0x1A;  array[1]=0x5e;    array[2]= 0x01;     // see p.34 of FDC2212-Q1 datasheet
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(3,array);        // transmit the first three bytes from array
  __delay_cycles(2000);

  // Read the CONFIG_MUX register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x1B;                      // register for Device ID
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,MUX_CNFG);      // receive 2 bytes from slave


  // Read the RCOUNT_0 register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x08;                      // register for Device ID
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);    // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,RCOUNT_0);     // receive 2 bytes from slave


  // Read the RCOUNT_1 register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x09;                      // register for Device ID
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,RCOUNT_1);     // receive 2 bytes from slave


  // Read the SCOUNT_0 register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x10;                      // register for Device ID
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);    // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,SCOUNT_0);     // receive 2 bytes from slave


  // Read the SCOUNT_1 register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x11;                      // register for Device ID
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);    // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,SCOUNT_1);     // receive 2 bytes from slave

  // Read the IDRIVE_0 register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x1E;                      // register for Device ID
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,&IDRIVE_0[1]);      // receive 2 bytes from slave


  // Read the IDRIVE_1 register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x1F;                      // register for Device ID
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,&IDRIVE_1[1]);      // receive 2 bytes from slave


  // Read the CLOCK_DIVIDERS_CH0 register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x14;                      // register for CLOCK_DIVIDERS_CH0
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,CK_DIV_0);      // receive 2 bytes from slave


  // Read the CLOCK_DIVIDERS_CH1 register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x15;                      // register for CLOCK_DIVIDERS_CH0
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,CK_DIV_1);      // receive 2 bytes from slave


  // Read the ERROR_CONFIG register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x19;                      // register for ERROR_CONFIG
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,ERR_CNFG);      // receive 2 bytes from slave


  // Read the CONFIG register
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a
  array[0] = 0x1a;                      // register for CONFIG
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
  while ( TI_USCI_I2C_notready() );     // wait for bus to be free
  TI_USCI_I2C_receive(2,CONFIG);        // receive 2 bytes from slave

                                          // begin the looping
  for(;;){
      // Measurement 1 ************
      P2OUT &= ~BIT1;                       // Turn off the Green LED
      P2OUT |= BIT2;                        // Turn on the RED LED
      __delay_cycles(10000000);

      // Read the MSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x02;                      // register for DATA_CH1    MSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,MSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_MSB = MSB_Channel_1[0] * 256 + MSB_Channel_1[1];

      // Read the LSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x03;                      // register for DATA_CH1_LSB    LSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,LSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_LSB = LSB_Channel_1[0] * 256 + LSB_Channel_1[1];

//      DataChannel_0 = DataChannel_0_MSB * 65536 + DataChannel_0_LSB ;
//      DataChannel_1 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB ;
      Measurement1 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB ;

      // Read the MSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x02;                      // register for DATA_CH1    MSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,MSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_MSB = MSB_Channel_1[0] * 256 + MSB_Channel_1[1];

      // Read the LSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x03;                      // register for DATA_CH1_LSB    LSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,LSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_LSB = LSB_Channel_1[0] * 256 + LSB_Channel_1[1];

//      DataChannel_0 = DataChannel_0_MSB * 65536 + DataChannel_0_LSB ;
//      DataChannel_1 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB ;
      Measurement1 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB ;

      // Measurement 2 ************
      P2OUT &= ~BIT2;                       // Turn off the Red LED
      __delay_cycles(10000000);
      P2OUT |= BIT1;                        // Turn on the Green LED
      __delay_cycles(10000000);

      // Read the MSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x02;                      // register for DATA_CH0    MSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,MSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_MSB = MSB_Channel_1[0] * 256 + MSB_Channel_1[1];

      // Read the LSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x03;                      // register for DATA_CH0_LSB    LSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,LSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_LSB = LSB_Channel_1[0] * 256 + LSB_Channel_1[1];

//      DataChannel_0 = DataChannel_0_MSB * 65536 + DataChannel_0_LSB ;
      Measurement2 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB ;
//      Measurement2 = DataChannel_1;
      // Read the MSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x02;                      // register for DATA_CH0    MSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,MSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_MSB = MSB_Channel_1[0] * 256 + MSB_Channel_1[1];

      // Read the LSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x03;                      // register for DATA_CH0_LSB    LSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,LSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_LSB = LSB_Channel_1[0] * 256 + LSB_Channel_1[1];

//      DataChannel_0 = DataChannel_0_MSB * 65536 + DataChannel_0_LSB ;
      Measurement2 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB ;
//      Measurement2 = DataChannel_1;
      P2OUT &= ~BIT1;
      P2OUT &= ~BIT2;
      __delay_cycles(10000000);


      // Measurement 3 ************
      P2OUT |= BIT1;                        // Turn on the Green LED
      P2OUT |= BIT2;                        // Turn on the RED LED
      __delay_cycles(10000000);

      // Read the MSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x02;                      // register for DATA_CH0    MSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,MSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_MSB = MSB_Channel_1[0] * 256 + MSB_Channel_1[1];

      // Read the LSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x03;                      // register for DATA_CH0_LSB    LSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,LSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_LSB = LSB_Channel_1[0] * 256 + LSB_Channel_1[1];

//      DataChannel_0 = DataChannel_0_MSB * 65536 + DataChannel_0_LSB ;
      Measurement3 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB ;
//    Measurement3 = DataChannel_1;
      P2OUT |= BIT1;                        // Turn on the Green LED
      P2OUT |= BIT2;                        // Turn on the RED LED
//      __delay_cycles(10000000);

      // Read the MSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x02;                      // register for DATA_CH0    MSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,MSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_MSB = MSB_Channel_1[0] * 256 + MSB_Channel_1[1];

      // Read the LSB of Channel 1 Data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz
      array[0] = 0x03;                      // register for DATA_CH0_LSB    LSB of channel 1 data
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_transmit(1,array);        // transmit the first byte from array

      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI
      while ( TI_USCI_I2C_notready() );     // wait for bus to be free
      TI_USCI_I2C_receive(2,LSB_Channel_1); // receive 2 bytes from FDC
      DataChannel_1_LSB = LSB_Channel_1[0] * 256 + LSB_Channel_1[1];

//      DataChannel_0 = DataChannel_0_MSB * 65536 + DataChannel_0_LSB ;
      Measurement3 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB ;
 //     Measurement3 = DataChannel_1;

      P2OUT &= ~BIT1;                           // turn off Green LED
      P2OUT &= ~BIT2;                           // turn off Red LED

      __delay_cycles(5000000);

      if((Measurement1 > (Measurement2 + MARGIN)) && (Measurement3 > (Measurement2 + MARGIN)))
      {
          P2OUT |= BIT1;//red
          __delay_cycles(2000000);
          P2OUT &= ~BIT1;
          __delay_cycles(2000000);
          P2OUT |= BIT1;
          __delay_cycles(2000000);
          P2OUT &= ~BIT1;
          __delay_cycles(2000000);
          P2OUT |= BIT1;
          __delay_cycles(2000000);
          P2OUT &= ~BIT1;
          __delay_cycles(2000000);
          P2OUT |= BIT1;
          __delay_cycles(2000000);
          P2OUT &= ~BIT1;
          __delay_cycles(2000000);
      }
      else
      {
          P2OUT |= BIT2;//green
          __delay_cycles(2000000);
          P2OUT &= ~BIT2;
          __delay_cycles(2000000);
          P2OUT |= BIT2;
          __delay_cycles(2000000);
          P2OUT &= ~BIT2;
          __delay_cycles(2000000);
          P2OUT |= BIT2;
          __delay_cycles(2000000);
          P2OUT &= ~BIT2;
          __delay_cycles(2000000);
          P2OUT |= BIT2;
          __delay_cycles(2000000);
          P2OUT &= ~BIT2;
          __delay_cycles(2000000);
      }                                         // end of if-else loop

      __delay_cycles(3000000);

    }                                           // end of for loop

 LPM3;                                          // low power mode 3

}

Dear Susan,

目前看起來I2c已經能夠正常傳遞資料，不過對於FDC2212的量測，仍然不清楚，

// Read the MSB of Channel 1 Data

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz

array[0] = 0x02; // register for DATA_CH1 MSB of channel 1 data

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_transmit(1,array); // transmit the first byte from array

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_receive(2,MSB_Channel_1); // receive 2 bytes from FDC

DataChannel_1_MSB = MSB_Channel_1[0] * 256 + MSB_Channel_1[1];

// Read the LSB of Channel 1 Data

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_transmitinit(0x2a,ISPEED);// init transmitting to slave 2a with baud rate SMCLK / 3f (3f = 63) that is, 8 MHz / 63 = 126 kHz

array[0] = 0x03; // register for DATA_CH1_LSB LSB of channel 1 data

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_transmit(1,array); // transmit the first byte from array

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_receiveinit(0x2a,ISPEED); // init receiving with USCI

while ( TI_USCI_I2C_notready() ); // wait for bus to be free

TI_USCI_I2C_receive(2,LSB_Channel_1); // receive 2 bytes from FDC

DataChannel_1_LSB = LSB_Channel_1[0] * 256 + LSB_Channel_1[1];

Measurement1 = DataChannel_1_MSB * 65536 + DataChannel_1_LSB;

程式中，重複兩次(Measurement1)，接下來還有Measurement2&3.

最後利用這個判斷式，判斷電路是否有效觸發:(Margin 設為500)

if((Measurement1 > (Measurement2 + MARGIN)) && (Measurement3 > (Measurement2 + MARGIN)))

能否請您指導該如何做實驗，來提升判斷的準確度，謝謝您!

0 Susan Yang 4 年多前回复 user6529956

TI__Guru**** 252096 points

之后我们将在下面的链接讨论

e2echina.ti.com/.../624314

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MSP430G2553 I2C SCLK 波型異常