MSP430F6726硬件I2C不能发送数据

只看该作者 · 2014-3-8 17:22

使用6726做主设备给从设备发送数据，从设备是ADS1113，代码如下：

#include <msp430.h>

unsigned char TXData;
unsigned char TXByteCtr;

int main(void)
{
WDTCTL = WDTPW | WDTHOLD;                      // Stop WDT

// Setup P2.0 UCB0SCL, P2.1 UCB0SDA
P2SEL |= BIT0 | BIT1;                            // Set P2.0,P2.1 to UCB0SCL, UCB0SDA

// Setup eUSCI_B0
UCB0CTLW0 |= UCSWRST;                            // Enable SW reset
UCB0CTLW0 |= UCMST | UCMODE_3 | UCSSEL_2;       // I2C Master, use SMCLK

UCB0BRW_L = 12;                                  // fSCL = SMCLK/12 = ~100kHz
UCB0BRW_H = 0;
UCB0I2CSA = 0x48;                               // Slave Address is 048h

UCB0CTLW0 &= ~UCSWRST;                         // Clear SW reset, resume operation
UCB0IE |= UCTXIE0;                               // Enable TX interrupt
TXData = 0x01;                                  // Holds TX data

while (1)
{
      TXByteCtr = 1;                               // Load TX byte counter

      while (UCB0CTLW0 & UCTXSTP) ;                // Ensure stop condition got sent
      UCB0CTLW0 |= UCTR|UCTXSTT;                // I2C TX, start condition
   // UCB0CTLW0 |=UCTXSTT;
      __bis_SR_register(LPM0_bits | GIE);          // Enter LPM0 w/ interrupts
      __no_operation();                            // Remain in LPM0 until all data
   // __delay_cycles(10000);                                           // is TX'd

      TXData++;                                  // Increment data byte
}
}

//------------------------------------------------------------------------------
// The USCIAB0_ISR is structured such that it can be used to transmit any
// number of bytes by pre-loading TXByteCtr with the byte count.
//------------------------------------------------------------------------------
// USCI_B0 interrupt service routine
#pragma vector = USCI_B0_VECTOR
__interrupt void USCI_B0_ISR(void)
{
switch (__even_in_range(UCB0IV, 30))
{
      case USCI_NONE: break;                      // No interrupts
      case USCI_I2C_UCALIFG: break;                // ALIFG
      case USCI_I2C_UCNACKIFG: break;             // NACKIFG
      case USCI_I2C_UCSTTIFG: break;             // STTIFG
      case USCI_I2C_UCSTPIFG: break;             // STPIFG
      case USCI_I2C_UCRXIFG3: break;             // RXIFG3
      case USCI_I2C_UCTXIFG3: break;             // TXIFG3
      case USCI_I2C_UCRXIFG2: break;             // RXIFG2
      case USCI_I2C_UCTXIFG2: break;             // TXIFG2
      case USCI_I2C_UCRXIFG1: break;             // RXIFG1
      case USCI_I2C_UCTXIFG1: break;             // TXIFG1
      case USCI_I2C_UCRXIFG0: break;             // RXIFG0
      case USCI_I2C_UCTXIFG0:                      // TXIFG0
      //  if (TXByteCtr)                         // Check TX byte counter
      //  {
            UCB0TXBUF = TXData;                // Load TX buffer
            TXByteCtr--;                         // Decrement TX byte counter
      //  }
      //  else
      // {
            UCB0IFG &= ~UCTXIFG;                // Clear USCI_B0 TX int flag
            UCB0CTL1 |= UCTXSTP;                // I2C stop condition
            __bic_SR_register_on_exit(LPM0_bits); // Exit LPM0
      // }
         break;
      case USCI_I2C_UCBCNTIFG: break;             // CNTIFG
      case USCI_I2C_UCCLTOIFG: break;             // LTOIFG
      case USCI_I2C_UCBIT9IFG: break;             // BIT9IFG
      default: break;
}
}
问题来了，程序在 ONLINE DEBUG的时候可以从监视窗口看到数据已发送到UCB0TXBUF ，但是从波形上看只能看到发送从设备地址，没有数据，求教啊！