MSP430F4152 同时使用UCA0_uart跟UCB0_iic时,中断标记无法正常清零.

我使用的是mSP430F4152

UCA0_uart与电脑连接,1200 8 N 1

UCB0_iic与MCP4152连接.

开发工具IAR for MSP430 5.30.1 不限时间试用版

unsigned char TXData;
unsigned char TXByteCtr;
unsigned char *PRxData;                     // Pointer to RX data
unsigned char RXByteCtr;
volatile unsigned char RxBuffer[5];         // Allocate 128 byte of RAM

const char string1[14] = { "Hello World\r\n" };
unsigned int j;

void IIC_init(void)
{
  P1OUT |= BIT4;
  P6DIR |= 0x06;
  P6OUT |= 0x60;
  P1OUT &=~ BIT4;
  P6SEL |= 0x06;                            // 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 0D0h
  UCB0CTL1 &= ~UCSWRST;                     // Clear SW reset, resume operation
  IFG2=0;
   IE2 |= UCB0TXIE;                          // Enable TX interrupt 
  IE2 |= UCB0RXIE;                          // Enable RX interrupt
}

void uart_init(void)
{
 P6SEL |= BIT5+BIT6;        // P6.5,6 = USCI_A0 RXD/TXD
 UCA0CTL1 |= UCSSEL_1;       // CLK = ACLK
 UCA0BR0 = 0x1B;         // 32k/1200

 UCA0BR1 = 0x00;         //
 UCA0MCTL = UCBRS1;        // Modulation
 UCA0CTL1 &= ~UCSWRST;       // **Initialize USCI state machine**
 IE2 &= ~UCA0TXIE; 
 IE2 |= UCA0RXIE;        // Enable USCI_A0 RX interrupt

IFG2 &= ~UCA0TXIFG;

}

#pragma vector=USCIAB0RX_VECTOR
__interrupt void USCI0RX_ISR(void)
{
  if (UCA0RXBUF == 'u')                     // 'u' received?
  {
    j = 0;
    IE2 |= UCA0TXIE;                        // Enable USCI_A0 TX interrupt
    UCA0TXBUF = string1[j++];
  }
}

//------------------------------------------------------------------------------
// 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.
//------------------------------------------------------------------------------
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
//  unsigned char itemp;
//  itemp= IFG2;
 
  if (IFG2&UCB0TXIFG)
  {
    if (TXByteCtr)                            // Check TX byte counter
    {
      UCB0TXBUF = TXData;                     // Load TX buffer
      TXByteCtr--;                            // Decrement TX byte counter
    }
    else
    {
      UCB0CTL1 |= UCTXSTP;                    // I2C stop condition      
    }
    IFG2 &= ~UCB0TXIFG;                     // Clear USCI_B0 TX int flag
  }
  if(IFG2&UCB0RXIFG)
  {
    RXByteCtr--;                              // Decrement RX byte counter
    if (RXByteCtr)
    {
      *PRxData++ = UCB0RXBUF;                 // Move RX data to address PRxData
      if (RXByteCtr == 1)                     // Only one byte left?
        UCB0CTL1 |= UCTXSTP;                  // Generate I2C stop condition
    }
    else
    {
      *PRxData = UCB0RXBUF;                   // Move final RX data to PRxData
    }
    IFG2 &= ~UCB0RXIFG;
  }
    if(IFG2&UCA0TXIFG)
    {
      UCA0TXBUF = string1[j++];      // TX next character
     
      if (j == sizeof string1 - 1)     // TX over?
      {
        IE2 &= ~UCA0TXIE;                       // Disable USCI_A0 TX interrupt
      }
     IFG2 &=~ UCA0TXIFG;
    }
  IFG2 &= UCA0RXIFG ;
}

       现象是串口接收到字母"u"后,会发送完字符串,但是不会停止发送,而是一直在发送,暂停程序后发现标记位UCA0TXIFG没有得到清除. j已经上升到很大的数值.单步在中断中运行后标记位UCA0TXIFG会被清零,恢复正常.

(iic处于0.5秒写一个字节,读4个字节的状态,由定时器控制节拍)