msp430 IIC 例子求助

只看该作者 · 2017-1-11 14:58

1. UCB0CTL1 |= UCTXSTT;                   // I2C start condition
这句执行就马上进入IIC中断吗？还是执行了下一句进入休眠后等到有数据才进入中断的？

2.为什么中断服务程序对应的中断向量是发送数据的？不应该是接收数据的吗

#include <msp430.h>

unsigned int RxByteCtr;
unsigned int RxWord;

int main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                // Stop WDT
  P1DIR |= BIT0;                         // P1.0 output
  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 = 0x4e;                      // Set slave address
  UCB0CTL1 &= ~UCSWRST;                   // Clear SW reset, resume operation
  IE2 |= UCB0RXIE;                         // Enable RX interrupt
  TACTL = TASSEL_2 + MC_2;                // SMCLK, contmode

  while (1)
  {
RxByteCtr = 2;                         // Load RX byte counter
UCB0CTL1 |= UCTXSTT;                   // I2C start condition
__bis_SR_register(CPUOFF + GIE);       // Enter LPM0, enable interrupts
                                          // Remain in LPM0 until all data
                                          // is RX'd

if (RxWord < 0x1d00)                   // >28C?
   P1OUT &= ~0x01;                      // No, P1.0 = 0
else
   P1OUT |= 0x01;                      // Yes, P1.0 = 1

__disable_interrupt();
TACCTL0 |= CCIE;                      // TACCR0 interrupt enabled
__bis_SR_register(CPUOFF + GIE);       // Enter LPM0, enable interrupts
                                          // Remain in LPM0 until TACCR0
                                          // interrupt occurs
TACCTL0 &= ~CCIE;                      // TACCR0 interrupt disabled
  }
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = TIMER0_A0_VECTOR
__interrupt void TA0_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(TIMER0_A0_VECTOR))) TA0_ISR (void)
#else
#error Compiler not supported!
#endif
{
  __bic_SR_register_on_exit(CPUOFF);       // Exit LPM0
}

// The USCIAB0TX_ISR is structured such that it can be used to receive any
// 2+ number of bytes by pre-loading RxByteCtr with the byte count.
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(USCIAB0TX_VECTOR))) USCIAB0TX_ISR (void)
#else
#error Compiler not supported!
#endif
{
  RxByteCtr--;                            // Decrement RX byte counter

  if (RxByteCtr)
  {
RxWord = (unsigned int)UCB0RXBUF << 8;  // Get received byte
if (RxByteCtr == 1)                   // Only one byte left?
   UCB0CTL1 |= UCTXSTP;                // Generate I2C stop condition
  }
  else
  {
RxWord |= UCB0RXBUF;                   // Get final received byte,
                                          // Combine MSB and LSB
__bic_SR_register_on_exit(CPUOFF);    // Exit LPM0
  }
}

只看该作者 · 2017-1-11 18:56

我用的轮询的硬件I2C，你需要的话，我可以发我代码给你看看，来个邮箱
中断的我还在调，还没调出来

只看该作者 · 2017-1-11 19:02

不过看你是直接配置寄存器的，我用的是库函数，推荐你个博文，对理解会好一些：
http://blog.csdn.net/xukai871105 ... ad52626f6f40fdeadaa

我是看了博文写出来的，然后需要添加一点，在UCB0CTL1 |= UCTXSTT; 需要等待UCTXSTT这个位置起来之后才可以继续下面的动作
你用中断的话，我师父说中断的是不需要等待这个位的置起的，看你选择什么方法咯