python中与PC机的MSP430FR5994 UART通信

Question

我试着学习如何使用UART，对于初学者，我只想把一些东西从微控制器发送到PC。我用这个代码文件给自己定位。

微控制器: MSP430FR5994 LaunchPad开发工具包

UART: FTDI电缆到Pins 2.6(UCA1RXD)和2.5(UCA1TXD)

该微控制器是在virtualbox Windows机器上使用CCS编写的。python脚本是在主linux系统上使用python3运行的。

我到目前为止所做的事：

用于接收的Python脚本

import serial                                     # import pySerial module
ComPort = serial.Serial('/dev/ttyUSB0',timeout=1) # open ttyUSB0

ComPort.baudrate = 9600                           # set Baud rate
ComPort.bytesize = 8                    # Number of data bits = 8
ComPort.parity   = 'N'                  # No parity
ComPort.stopbits = 1                    # Number of Stop bits = 1

data = ComPort.read()               # Wait and read data from serial port
print(data)                             # print the received data

ComPort.close()                         # Close the COM Port

用于微控制器的C脚本

#include <msp430.h> 
void UART_init(void);

void main(void) {
  WDTCTL = WDTPW | WDTHOLD;   //Stop watchdog timer
  PM5CTL0 &= ~LOCKLPM5;

  UART_init();

  UCA1TXBUF = 'A';

}

void UART_init(void){
    P2SEL1 |= BIT5 + BIT6;              //Activate Pin for UART use
    P2SEL0 &= ~BIT5 + ~BIT6;            //Activate Pin for UART use

    UCA1CTLW0 |= UCSSEL_2;              //Select clock SMCLK

    UCA1BRW = 0x6;                      //Set Baud rate 9600 : UCA1BRW = INT(F_CPU/BAUD_soll) =         INT(1MHz/9600) = 104 with oversampling: 6
    UCA1MCTLW |= UCBRS5 + UCOS16 + UCBRF3;     //Modulation according to datasheet table: UCBRS = 0x20 = b100000 and UCOS16 = 1 and UCBRF = 8 = 0x8 = b1000

    UCA1CTLW0 &= ~UCSWRST;  //Reset UART module
 }

然后我闪现微控制器代码，然后运行python代码。但我什么都没得到。在1s超时之后，我只得到b'‘。

哪里可能有错误？没有联系吗？引脚有问题吗？因为我只是在学习它，我真的不知道为什么它不起作用。也许你有一些建议:)

问好，散乱的

到目前为止已经完成了，因此我尝试了以下几种方法，但仍然无法工作：

进入低功耗模式

#include <msp430.h> 
void UART_init(void);

void main(void) {
  WDTCTL = WDTPW | WDTHOLD;   //Stop watchdog timer
  PM5CTL0 &= ~LOCKLPM5;

  UART_init();

  UCA1TXBUF = 'A';
  __bis_SR_register(LPM0_bits);

}

void UART_init(void){
    P2SEL1 |= BIT5 + BIT6;              //Activate Pin for UART use
    P2SEL0 &= ~BIT5 + ~BIT6;            //Activate Pin for UART use

    UCA1CTLW0 |= UCSSEL_2;              //Select clock SMCLK

    UCA1BRW = 0x6;                      //Set Baud rate 9600 : UCA1BRW = INT(F_CPU/BAUD_soll) =         INT(1MHz/9600) = 104 with oversampling: 6
    UCA1MCTLW |= UCBRS5 + UCOS16 + UCBRF3;     //Modulation according to datasheet table: UCBRS = 0x20 = b100000 and UCOS16 = 1 and UCBRF = 8 = 0x8 = b1000

    UCA1CTLW0 &= ~UCSWRST;  //Reset UART module
}

永远不要在没有进入低功耗模式的情况下退出。

#include <msp430.h> 
void UART_init(void);

void main(void) {
  WDTCTL = WDTPW | WDTHOLD;   //Stop watchdog timer
  PM5CTL0 &= ~LOCKLPM5;

  UART_init();

  while(1){
  UCA1TXBUF = 'A';
  __bis_SR_register(LPM0_bits); // with and without the entering LPM0 mode
  }
}

void UART_init(void){
    P2SEL1 |= BIT5 + BIT6;              //Activate Pin for UART use
    P2SEL0 &= ~BIT5 + ~BIT6;            //Activate Pin for UART use

    UCA1CTLW0 |= UCSSEL_2;              //Select clock SMCLK

    UCA1BRW = 0x6;                      //Set Baud rate 9600 : UCA1BRW = INT(F_CPU/BAUD_soll) =         INT(1MHz/9600) = 104 with oversampling: 6
    UCA1MCTLW |= UCBRS5 + UCOS16 + UCBRF3;     //Modulation according to datasheet table: UCBRS = 0x20 = b100000 and UCOS16 = 1 and UCBRF = 8 = 0x8 = b1000

    UCA1CTLW0 &= ~UCSWRST;  //Reset UART module
 }

我还试着插入

 while(!(UCA1IFG & UCTXIFG));

在这两种情况下。最后，我也尝试了一个中断：

#include <msp430.h> 
void UART_init(void);

void main(void) {
  WDTCTL = WDTPW | WDTHOLD;   //Stop watchdog timer
  PM5CTL0 &= ~LOCKLPM5;

  UART_init();

  __bis_SR_register(LPM0_bits + GIE);

}

void UART_init(void){
    P2SEL1 |= BIT5 + BIT6;              //Activate Pin for UART use
    P2SEL0 &= ~BIT5 + ~BIT6;            //Activate Pin for UART use

    UCA1CTLW0 |= UCSSEL_2;              //Select clock SMCLK

    UCA1BRW = 0x6;                      //Set Baud rate 9600 : UCA1BRW = INT(F_CPU/BAUD_soll) =         INT(1MHz/9600) = 104 with oversampling: 6
    UCA1MCTLW |= UCBRS5 + UCOS16 + UCBRF3;     //Modulation according to datasheet table: UCBRS = 0x20 = b100000 and UCOS16 = 1 and UCBRF = 8 = 0x8 = b1000

    UCA1CTLW0 &= ~UCSWRST;  //Reset UART module
    UCA1IE |= UCTXIE;       //enable transmitting interrupts
}

#pragma vector= EUSCI_A1_VECTOR
__interrupt void USCI_A1_ISR(void){
   while(!(UCA1IFG & UCTXIFG)); //with and without this line
   UCA1TXBUF = 'A';
}

Answer 1

好哇！我发现我的错误..。这真的很蠢..。下面这句话让我明白了这一点：

还请记住，UART连接从一个设备交叉到另一个设备。MSP430 UART TX ->外部设备UART RX和MSP430 UART RX <-外部设备UART TX。

我真的很抱歉！现在我换好了电缆，一切都很好。有点尴尬。但是，现在起作用了:D

谢谢你的回答和耐心。

Answer 2

该字节是在微控制器开始运行时发送的。如果您稍后启动Python程序，则为时已晚。

您不应该从main()返回，因为没有可返回的操作系统；所发生的事情是未定义的。若要停止执行代码但保留SMCLK (您需要完成UART传输)，请输入LPM0。