lab-12-4619_s_i2c.c

MSP430FG4619的iic子程序

//******************************************************************************
//   MSP430xG41x Demo - USCI_B0 I2C Slave RX multiple bytes from MSP430 Master
//
//   Description: This demo connects two MSP430's via the I2C bus. The master
//   transmits to the slave. This is the slave code. The interrupt driven
//   data receiption is demonstrated using the USCI_B0 RX interrupt.
//
//                                 /|\  /|\
//                MSP430xG461x     10k  10k    MSP430xG461x
//                    slave         |    |        master
//              -----------------   |    |  -----------------
//            -|XIN  P3.1/UCB0SDA|<-|---+->|P3.1/UCB0SDA  XIN|-
//       32kHz |                 |  |      |                 | 32kHz
//            -|XOUT             |  |      |             XOUT|-
//             |     P3.2/UCB0SCL|<-+----->|P3.2/UCB0SCL     |
//             |                 |         |                 |
//
//   Andreas Dannenberg/ M. Mitchell
//   Texas Instruments Inc.
//   October 2006
//   Built with IAR Embedded Workbench Version: 3.41A
//******************************************************************************
#include "msp430xG46x.h"

unsigned char *PRxData;                     
unsigned char RXByteCtr;
volatile unsigned char RxBuffer[128];       // 接收数据数组

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // 关看门狗
  P3SEL |= 0x06;                            //  USCI_B0 选择I2C功能
  UCB0CTL1 |= UCSWRST;                      // 使能 SW 复位
  UCB0CTL0 = UCMODE_3 + UCSYNC;             // I2C从机 同步模式
  UCB0I2COA = 0x48;                         // 从机地址 048h
  UCB0CTL1 &= ~UCSWRST;                     // 清 SW 复位  
  UCB0I2CIE |= UCSTPIE + UCSTTIE;           // 使能 STT 、 STP 中断
  IE2 |= UCB0RXIE;                          // 使能接收中断
  while (1)
  {
    PRxData = (unsigned char *)RxBuffer;    // 接收缓存
    RXByteCtr = 0;                          // 清 RX 字节长度
    __bis_SR_register(CPUOFF + GIE);        //进入低功耗  LPM0  
    __no_operation();                       // 
  }                                        
}

//------------------------------------------------------------------------------
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
  *PRxData++ = UCB0RXBUF;                   // 发送数据
  RXByteCtr++;                              // 指针增加
}


//------------------------------------------------------------------------------
#pragma vector = USCIAB0RX_VECTOR
__interrupt void USCIAB0RX_ISR(void)
{
  UCB0STAT &= ~(UCSTPIFG + UCSTTIFG);       // 清中断标志
  if (RXByteCtr)                            // 校验数据长度
    __bic_SR_register_on_exit(CPUOFF);      //退出低功耗 LPM0  
}