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关于f5529串口通信的问题



这是一段官方的例程

#pragma vector=USCI_A0_VECTOR
__interrupt void USCI_A0_ISR(void)
{
switch(__even_in_range(UCA0IV,4))
{
case 0:break; // Vector 0 - no interrupt
case 2: // Vector 2 - RXIFG
while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = UCA0RXBUF; // TX -> RXed character
break;
case 4:break; // Vector 4 - TXIFG
default: break;
}
}

请问这里的switch中case0,case2,case4分别是什么意思,如果我想让f5529接收到电脑传来的数据后点亮上面的一盏LED,相应的代码应该添加在什么位置?

  • 你好,

    你可以把全部程序贴出来吗?

    你知道你用的USCI_A0作为SPI还是串口来使用的?

    UCA0IV是一个寄存器,他们共用一个中断源,不同的标志位表示不用原因的中断,但是都是USCI_A0接收到数据产生的中断。

    所以swith case是为了根据不同原因,触发不同事件。

    如果我想让f5529接收到电脑传来的数据后点亮上面的一盏LED,相应的代码应该添加在中断函数里面就可以了。

  • 你好,这个是完整的例程

    /* --COPYRIGHT--,BSD_EX
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    * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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    * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
    * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
    * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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    * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
    * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    *
    *******************************************************************************
    *
    * MSP430 CODE EXAMPLE DISCLAIMER
    *
    * MSP430 code examples are self-contained low-level programs that typically
    * demonstrate a single peripheral function or device feature in a highly
    * concise manner. For this the code may rely on the device's power-on default
    * register values and settings such as the clock configuration and care must
    * be taken when combining code from several examples to avoid potential side
    * effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
    * for an API functional library-approach to peripheral configuration.
    *
    * --/COPYRIGHT--*/
    //******************************************************************************
    // MSP430F552x Demo - USCI_A0, 115200 UART Echo ISR, DCO SMCLK
    //
    // Description: Echo a received character, RX ISR used. Normal mode is LPM0.
    // USCI_A0 RX interrupt triggers TX Echo.
    // Baud rate divider with 1048576hz = 1048576/115200 = ~9.1 (009h|01h)
    // ACLK = REFO = ~32768Hz, MCLK = SMCLK = default DCO = 32 x ACLK = 1048576Hz
    // See User Guide for baud rate divider table
    //
    // MSP430F552x
    // -----------------
    // /|\| |
    // | | |
    // --|RST |
    // | |
    // | P3.3/UCA0TXD|------------>
    // | | 115200 - 8N1
    // | P3.4/UCA0RXD|<------------
    //
    // Bhargavi Nisarga
    // Texas Instruments Inc.
    // April 2009
    // Built with CCSv4 and IAR Embedded Workbench Version: 4.21
    //******************************************************************************

    #include <msp430.h>

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

    P3SEL |= BIT3+BIT4; // P3.3,4 = USCI_A0 TXD/RXD
    UCA0CTL1 |= UCSWRST; // **Put state machine in reset**
    UCA0CTL1 |= UCSSEL_2; // SMCLK
    UCA0BR0 = 9; // 1MHz 115200 (see User's Guide)
    UCA0BR1 = 0; // 1MHz 115200
    UCA0MCTL |= UCBRS_1 + UCBRF_0; // Modulation UCBRSx=1, UCBRFx=0
    UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
    UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt

    __bis_SR_register(LPM0_bits + GIE); // Enter LPM0, interrupts enabled
    __no_operation(); // For debugger
    }

    // Echo back RXed character, confirm TX buffer is ready first
    #pragma vector=USCI_A0_VECTOR
    __interrupt void USCI_A0_ISR(void)
    {
    switch(__even_in_range(UCA0IV,4))
    {
    case 0:break; // Vector 0 - no interrupt
    case 2: // Vector 2 - RXIFG
    while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
    UCA0TXBUF = UCA0RXBUF; // TX -> RXed character
    break;
    case 4:break; // Vector 4 - TXIFG
    default: break;
    }
    }

    我是作为串口使用的,串口的接受和发送是共用一个中断吗?可不可以用两个中断,一个是接受,另一个是发送?

  • 注释写得很清楚啊,

    0- 没有中断

    2- 接收数据中断,当RXBUF非空时触发

    4-发送数据中断,当TXBUF为空时触发

    注意这里的发送数据中断,当TXBUF为空时触发,并不是说发送数据完成触发中断。而是当TXBUF的数据放入移位寄存器后就会触发。