I2C模块有些不理解

只看该作者 · 2014-8-31 11:10

#include <msp430.h>

unsigned char TXByteCtr;
unsigned char RXByteCtr;

unsigned char second;

unsigned char read=0;

int 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
  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 = 0xD0>>1;                      // Slave Address is 048h
  UCB0CTL1 &= ~UCSWRST;                   // Clear SW reset, resume operation

  while (1)
  {
IE2 |= UCB0TXIE;                         // Enable TX interrupt
IE2 &= ~UCB0RXIE;
TXByteCtr = 1;                         // 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
                                          // Remain in LPM0 until all data
                                          // is TX'd

IE2 |= UCB0RXIE;
IE2 &= ~UCB0TXIE;
RXByteCtr = 1;
while (UCB0CTL1 & UCTXSTP);
UCB0CTL1 &= ~UCTR;
UCB0CTL1 |= UCTXSTT;
__bis_SR_register(CPUOFF + GIE);

  }
}

//------------------------------------------------------------------------------
// The USCIAB0TX_ISR is structured such that it can be used to transmit any
// number of bytes by pre-loading TXByteCtr with the byte count. Also, TXData
// points to the next byte to transmit.
//------------------------------------------------------------------------------
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
  if (TXByteCtr)                         // Check TX byte counter
  {
UCB0TXBUF = 0x00;                // Load TX buffer
TXByteCtr--;                         // Decrement TX byte counter
  }
  else
  {
UCB0CTL1 |= UCTXSTP;                   // I2C stop condition
IFG2 &= ~UCB0TXIFG;                   // Clear USCI_B0 TX int flag
__bic_SR_register_on_exit(CPUOFF);    // Exit LPM0
  }
}

#pragma vector = USCIAB0RX_VECTOR
__interrupt void USCIAB0RX_ISR(void)
{
  if (RXByteCtr)                         // Check TX byte counter
  {
second=UCB0RXBUF;                // Load TX buffer
RXByteCtr--;                         // Decrement TX byte counter
  }
  else
  {
UCB0CTL1 |= UCTXSTP;                   // I2C stop condition
IFG2 &= ~UCB0RXIFG;                   // Clear USCI_B0 TX int flag
__bic_SR_register_on_exit(CPUOFF);    // Exit LPM0
  }
}

只看该作者 · 2014-8-31 11:11

在德州给的样例一中读取的是TMP100的数据，中断使能也是UCB0RXIE，可为什么用的中断向量却是#pragma vector = USCIAB0TX_VECTOR，然后再他给的其他样例中也看到很多类似的行为。另外写的一个I2C的程序也就一直调试不对，430做主控，先发送后读取的一个简单程序希望各位能不吝指教。
希望读取0xD0的器件上0x00的位置上的一个数据。