430g2553 IIC

首先感谢你的精彩分析和中肯建议，虽然我不是软件工程师，但这代码确实太烂，并对自己的无理表示道歉。

1.这个程序用于2553做主控的蓝牙音箱中，用TI的数字功放，main函数功能主要有四个：a.硬件的初始化（不包括功放）；b.功放初始化；c.按键操作；d.显示控制。

用I2C来实现对功放的初始化，我把功能分布调试，所以没有贴main()，初始化数据在另一个文件中，这段代码是从官方的例程12抄过来的，所以没加注释。

2.功放初始化：a.对功放指定寄存器写数据；b.读出指定寄存器值计算后重新写入该寄存器

                       （读操作先写入被读寄存器地址，再进行当前地址寄存器读取，所以在RX内先调用了TX）（TX\RX每次只完成单个字节数据（不包括地址）的读写）

3.RX、TX内每次进行调用都初始化I2C，这是对应例程i2c_12中的tx、rx set_up，按照我对UCSWRST的理解，I2C初始化应该和IO一起，初始化一遍即可，把SA放到TX、RX函数中。不是一定要照抄例程，只是觉得刚开始还是尽量接近官方例程。

4.在DS中，如果没理解错，T\RX flag共用一个向量（Status flag共用一个向量），参照例程，我还是把他们放一起。

5.注释一下我贴的代码

#ifndef SIMPLE_I2C_H
#define SIMPLE_I2C_H
#endif
#define uchar unsigned char

uchar TRFlag;     //判断是发送还是接收中断，1->tx
uchar DataFlag=0;   //判断是只发送功放寄存器地址还是需发数据，0->需加数据
uchar TxData[2];       //装寄存器地址或者+数据
uchar *PTxData;     //指向上面的数组
//uchar Rxdata;
uchar Txctr;            //发送计数
uchar I2C_buf1;      //存储要发送的或者接收的I2C数据

void init_i2c(void);
void I2Cm_Tx(uchar valueReg,uchar RegAddress,uchar DeviceAddress);      //变量：数据I2C_buf1、寄存器地址、功放地址
void I2Cm_Rx(uchar valueReg,uchar RegAddress,uchar DeviceAddress);

#pragma vector=USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void){
  if(TRFlag==1){                                                  //TRFlag、Txctr在TX建立过程中赋值
    if(Txctr){
      Txctr--;
      UCB0TXBUF=*PTxData++;      
      __bic_SR_register_on_exit(CPUOFF);   // 按照对例程的理解，这句应该不要，STP不发，不断中断才会进行完Txctr-到0，再到下面给STP，按照例程中  

                                                                           recieve()\transmit()， 我在每次调用TX RX中断返回后都while 已STP发送，这样这里需要加这一句跳出低功耗，不加不会循环不

                                                                             会发STP，加了更不会循环
    }
    else{                                                                 //实际这里没有执行到
      UCB0CTL1|=UCTXSTP;
      IFG2&=~UCB0TXIFG;
      __bic_SR_register_on_exit(CPUOFF);
    }
  }
  else{
    I2C_buf1=UCB0RXBUF;
    UCB0CTL1|=UCTXSTP;
    IFG2&=~UCB0RXIFG;
    __bic_SR_register_on_exit(CPUOFF);
  }
}

void I2Cm_Tx(uchar valueReg,uchar RegAddress,uchar DeviceAddress){
  _DINT();
  TRFlag=1;                           //发送标志
  if(DataFlag==1){                //RX函数内部DataFlag置1后紧接着调用TX，如通过RX间接调用TX，DataFlag马上清0，避免影响TX后续的直接调用
    Txctr=1;
    DataFlag=0;
  }
  else{
    Txctr=2;
  }
  IE2&=~UCB0RXIE;                                        //初始化
  while(UCB0CTL1&UCTXSTP);
  UCB0CTL1|=UCSWRST;
  UCB0CTL0=UCMST+UCMODE_3+UCSYNC;
  UCB0CTL1=UCSSEL_2+UCSWRST;                               //选择SMCLK12分频为时钟，例程中未初始化主时钟，默认S/MCLK为800K，实际不超过SCL不超过67K

                                                                                                           ，我写的main中也为800K
  UCB0BR0=12;
  UCB0BR1=0;
  UCB0I2CSA=DeviceAddress;
  UCB0CTL1&=~UCSWRST;
  IE2|=UCB0TXIE;
  TxData[0]=RegAddress;
  TxData[1]=valueReg;                            //通过RX间接调用TX时，此值为I2C_buf1,但不发送
  PTxData=TxData;                                  //指针赋值
  while(UCB0CTL1&UCTXSTP);
  UCB0CTL1|=UCTR+UCTXSTT;
  __bis_SR_register(CPUOFF+GIE);      //enter interrupt
  while(UCB0CTL1&UCTXSTP);            //return to this
}

void I2Cm_Rx(uchar valueReg,uchar RegAddress,uchar DeviceAddress){
  _DINT();
  uchar temp_dev,temp_reg;                        //RX TX参数传递
  temp_dev=DeviceAddress;
  temp_reg=RegAddress;
  TRFlag=0;                                            //接收标志，这个应该放在调用TX后
  DataFlag=1;
  I2Cm_Tx(0x00,temp_reg,temp_dev);
  IE2&=~UCB0TXIE;                                           //初始化
  while(UCB0CTL1&UCTXSTP);
  UCB0CTL1|=UCSWRST;
  UCB0CTL0=UCMST+UCMODE_3+UCSYNC;
  UCB0CTL1=UCSSEL_2+UCSWRST;
  UCB0BR0=12;
  UCB0BR1=0;
  UCB0I2CSA=temp_dev;
  UCB0CTL1&=~UCSWRST;
  IE2|=UCB0RXIE;
  while(UCB0CTL1&UCTXSTP);
  UCB0CTL1|=UCTXSTT;
  __bis_SR_register(CPUOFF+GIE);
  while(UCB0CTL1&UCTXSTP);
}

void init_i2c(void){
  P1SEL|=BIT6+BIT7;
  P1SEL2|=BIT6+BIT7;
}

6.参考的官方例程

//******************************************************************************
//  MSP430G2xx3 Demo - USCI_B0 I2C Master TX/RX multiple bytes from MSP430 Slave
//                     with a repeated start in between TX and RX operations.
//
//  Description: This demo connects two MSP430's via the I2C bus. The master
//  transmits to the slave, then a repeated start is generated followed by a
//  receive operation. This is the master code. This code demonstrates how to
//  implement an I2C repeated start with the USCI module using the USCI_B0 TX
//  interrupt.
//  ACLK = n/a, MCLK = SMCLK = BRCLK = default DCO = ~1.2MHz
//
//    ***to be used with msp430x22x4_uscib0_i2c_13.c***
//
//                                /|\  /|\
//               MSP430F24x      10k  10k     MSP430G2xx3
//                   slave         |    |        master
//             -----------------   |    |  -----------------
//           -|XIN  P3.1/UCB0SDA|<-|---+->|P3.1/UCB0SDA  XIN|-
//            |                 |  |      |                 |
//           -|XOUT             |  |      |             XOUT|-
//            |     P3.2/UCB0SCL|<-+----->|P3.2/UCB0SCL     |
//            |                 |         |                 |
//
//  D. Dang
//  Texas Instruments Inc.
//  February 2011
//  Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10
//******************************************************************************
#include "msp430g2553.h"

#define NUM_BYTES_TX 3                         // How many bytes?
#define NUM_BYTES_RX 2

int RXByteCtr, RPT_Flag = 0;                // enables repeated start when 1
volatile unsigned char RxBuffer[128];       // Allocate 128 byte of RAM
unsigned char *PTxData;                     // Pointer to TX data
unsigned char *PRxData;                     // Pointer to RX data
unsigned char TXByteCtr, RX = 0;
unsigned char MSData = 0x55;

void Setup_TX(void);
void Setup_RX(void);
void Transmit(void);
void Receive(void);

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  P1SEL |= BIT6 + BIT7;                     // Assign I2C pins to USCI_B0
  P1SEL2|= BIT6 + BIT7;                     // Assign I2C pins to USCI_B0
 
  while(1){
   
  //Transmit process
  Setup_TX();
  RPT_Flag = 1;
  Transmit();
  while (UCB0CTL1 & UCTXSTP);             // Ensure stop condition got sent
 
  //Receive process
  Setup_RX();
  Receive();
  while (UCB0CTL1 & UCTXSTP);             // Ensure stop condition got sent
  }
}

//-------------------------------------------------------------------------------
// The USCI_B0 data ISR is used to move received data from the I2C slave
// to the MSP430 memory. It is structured such that it can be used to receive
// any 2+ number of bytes by pre-loading RXByteCtr with the byte count.
//-------------------------------------------------------------------------------
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
  if(RX == 1){                              // Master Recieve?
  RXByteCtr--;                              // Decrement RX byte counter
  if (RXByteCtr)
  {
    *PRxData++ = UCB0RXBUF;                 // Move RX data to address PRxData
  }
  else
  {
    if(RPT_Flag == 0)
        UCB0CTL1 |= UCTXSTP;                // No Repeated Start: stop condition
      if(RPT_Flag == 1){                    // if Repeated Start: do nothing
        RPT_Flag = 0;
      }
    *PRxData = UCB0RXBUF;                   // Move final RX data to PRxData
    __bic_SR_register_on_exit(CPUOFF);      // Exit LPM0
  }}
 
  else{                                     // Master Transmit
      if (TXByteCtr)                        // Check TX byte counter
  {
    UCB0TXBUF = MSData++;                   // Load TX buffer
    TXByteCtr--;                            // Decrement TX byte counter
  }
  else
  {
    if(RPT_Flag == 1){
    RPT_Flag = 0;
    PTxData = &MSData;                      // TX array start address
    TXByteCtr = NUM_BYTES_TX;                  // Load TX byte counter
    __bic_SR_register_on_exit(CPUOFF);
    }
    else{
    UCB0CTL1 |= UCTXSTP;                    // I2C stop condition
    IFG2 &= ~UCB0TXIFG;                     // Clear USCI_B0 TX int flag
    __bic_SR_register_on_exit(CPUOFF);      // Exit LPM0
    }
  }
 }
 
}

void Setup_TX(void){
  _DINT();
  RX = 0;
  IE2 &= ~UCB0RXIE; 
  while (UCB0CTL1 & UCTXSTP);               // Ensure stop condition got sent// Disable RX interrupt
  UCB0CTL1 |= UCSWRST;                      // Enable SW reset
  UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC;     // I2C Master, synchronous mode
  UCB0CTL1 = UCSSEL_2 + UCSWRST;            // Use SMCLK, keep SW reset
  UCB0BR0 = 12;                             // fSCL = SMCLK/12 = ~100kHz
  UCB0BR1 = 0;
  UCB0I2CSA = 0x48;                         // Slave Address is 048h
  UCB0CTL1 &= ~UCSWRST;                     // Clear SW reset, resume operation
  IE2 |= UCB0TXIE;                          // Enable TX interrupt
}
void Setup_RX(void){
  _DINT();
  RX = 1;
  IE2 &= ~UCB0TXIE; 
  UCB0CTL1 |= UCSWRST;                      // Enable SW reset
  UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC;     // I2C Master, synchronous mode
  UCB0CTL1 = UCSSEL_2 + UCSWRST;            // Use SMCLK, keep SW reset
  UCB0BR0 = 12;                             // fSCL = SMCLK/12 = ~100kHz
  UCB0BR1 = 0;
  UCB0I2CSA = 0x48;                         // Slave Address is 048h
  UCB0CTL1 &= ~UCSWRST;                     // Clear SW reset, resume operation
  IE2 |= UCB0RXIE;                          // Enable RX interrupt
}
void Transmit(void){
    PTxData = &MSData;                      // TX array start address
    TXByteCtr = NUM_BYTES_TX;                  // Load TX byte counter
    while (UCB0CTL1 & UCTXSTP);             // Ensure stop condition got sent
    UCB0CTL1 |= UCTR + UCTXSTT;             // I2C TX, start condition
    __bis_SR_register(CPUOFF + GIE);        // Enter LPM0 w/ interrupts
}
void Receive(void){
    PRxData = (unsigned char *)RxBuffer;    // Start of RX buffer
    RXByteCtr = NUM_BYTES_RX-1;              // Load RX byte counter
    while (UCB0CTL1 & UCTXSTP);             // Ensure stop condition got sent
    UCB0CTL1 |= UCTXSTT;                    // I2C start condition
    __bis_SR_register(CPUOFF + GIE);        // Enter LPM0 w/ interrupts
}