stm32的usart2作为485接口收发数据的难题，跪求指点

只看该作者 · 2018-1-27 15:57

向各位大侠求助啊，两个问题：1、为什么电脑的串口调试助手只收到一遍的ABCDEFG........XYZ 以后就不发了
2、485.c中的USART2_IRQHandler是串口收到数据才会被调用的，实际上是串口发送了ABCD就会触发set_usart_485_handler发生蜂鸣和继电器开关动作

这个是485.c
#include "bitband.h"
#include "usart_485.h"

typedef void (*set_U_485_handler) (unsigned char c);
set_U_485_handler handler_485;

void usart_485_init(void)
{
      GPIO_InitTypeDef Gpio_Value;
      USART_InitTypeDef Usart_Value;
      NVIC_InitTypeDef Nvic_Value;

      RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOD, ENABLE);
      RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

      Gpio_Value.GPIO_Mode = GPIO_Mode_AF;
      Gpio_Value.GPIO_OType = GPIO_OType_PP;
      Gpio_Value.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
      Gpio_Value.GPIO_PuPd = GPIO_PuPd_NOPULL;
      Gpio_Value.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_Init(GPIOA, &Gpio_Value);

      GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);
      GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2);

      Gpio_Value.GPIO_Mode = GPIO_Mode_OUT;
      Gpio_Value.GPIO_OType = GPIO_OType_PP;
      Gpio_Value.GPIO_Pin = GPIO_Pin_6;
      Gpio_Value.GPIO_PuPd = GPIO_PuPd_NOPULL;
      Gpio_Value.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_Init(GPIOD, &Gpio_Value);

      PDOut(6) = 1;//PD6输出高电平，它连接了MAX485ESA的DE和RE

      Usart_Value.USART_BaudRate = 115200;
      Usart_Value.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
      Usart_Value.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
      Usart_Value.USART_Parity = USART_Parity_No;
      Usart_Value.USART_StopBits = USART_StopBits_1;
      Usart_Value.USART_WordLength = USART_WordLength_8b;
      USART_Init(USART2, &Usart_Value);

      Nvic_Value.NVIC_IRQChannel = USART2_IRQn;
      Nvic_Value.NVIC_IRQChannelCmd = ENABLE;
      Nvic_Value.NVIC_IRQChannelPreemptionPriority = 2;
      Nvic_Value.NVIC_IRQChannelSubPriority = 2;
      NVIC_Init(&Nvic_Value);

      USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
      USART_Cmd(USART2, ENABLE);
}

void usart_485_send(unsigned char c)
{
      //PDOut(6) = 1;
      USART_SendData(USART2, (uint16_t)c);
      while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET);
      USART_ClearFlag(USART2, USART_FLAG_TXE);
      //PDOut(6) = 0;
}

unsigned char usart_485_recv(void)
{
      return 0;
}

void set_485_recv_handler(set_U_485_handler h)
{
      handler_485 = h;
}

void USART2_IRQHandler(void)
{
      if(USART_GetITStatus(USART2, USART_IT_RXNE) == SET)
      {
            handler_485(USART_ReceiveData(USART2));
            USART_ClearITPendingBit(USART2, USART_IT_RXNE);
      }
}

以下是main.c
void set_usart_485_handler(unsigned char c)
{
      switch(c)
      {
            case 'A': switch_on(0); buzzer_on(); break;
            case 'B': switch_on(1); buzzer_off(); break;
            case 'C': switch_on(2); buzzer_on(); break;
            case 'D': switch_off(0); switch_off(1); switch_off(2); buzzer_off(); break;
      }
}

int main(void)
{
      //unsigned char c_232 = 'A';
      unsigned char c_485 = 'E';
      //unsigned char c_232_buf[11] = "1111111111";

      NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

      led_init();
      buzzer_init();
      switch_init();
      button_init();
      delay_init();
      eint_init();
      //usart_232_init();
      usart_485_init();

      //set_232_recv_handler(set_usart_232_handler);
      set_485_recv_handler(set_usart_485_handler);

      while(1)
      {
            //usart_232_send(c_232++);
            usart_485_send(c_485++);
            delay_ms(10);//tzx addded
            //if(c_232 >= 'Z')
            //       c_232 = 'A';
            if(c_485 >= 'Z')
                     c_485 = 'E';
            switch_on(0);
            delay_ms(500);
            switch_off(0);
            delay_ms(500);
            //c_232_buf[9]++;
      }
}