stm32f429的rs485通信问题（新手求助）

墨问12 · 发表于 2019-6-4 15:07:23

我用的是429提供的HAL库版rs485例程，使用两块板子通信，为什么只能一端发送数据另一端接收，而另一端发送的数据无法接收？

peng1554 · 发表于 2019-6-4 17:28:52

拍照下两板子间的接法

触电丶 · 发表于 2019-6-4 17:35:32

代码和连线贴出来看一下

墨问12 · 发表于 2019-6-4 19:31:21

peng1554 发表于 2019-6-4 17:28
拍照下两板子间的接法

A接A，B接B，共地

peng1554 · 发表于 2019-6-4 19:34:29

墨问12 发表于 2019-6-4 19:31
A接A，B接B，共地

硬件接法没问题~~

墨问12 · 发表于 2019-6-4 19:38:01

本帖最后由墨问12 于 2019-6-4 19:47 编辑

触电丶发表于 2019-6-4 17:35
代码和连线贴出来看一下

UART_HandleTypeDef USART2_RS485Handler;  //USART2¾ä±ú(óÃóúRS485)

#if EN_USART2_RX                //èç1ûê1ÄüáË½óêÕ
//½óêÕ»o′æÇø
u8 RS485_RX_BUF[64];       //½óêÕ»o3å,×î′ó64¸ö×Ö½ú.
//½óêÕμ½μÄêy¾Y3¤¶è
u8 RS485_RX_CNT=0;

void USART2_IRQHandler(void)
{
u8 res;
if((__HAL_UART_GET_FLAG(&USART2_RS485Handler,UART_FLAG_RXNE)!=RESET))  //½óêÕÖD¶Ï
            {
   HAL_UART_Receive(&USART2_RS485Handler,&res,1,1000);
               if(RS485_RX_CNT<64)
               {
                        RS485_RX_BUF[RS485_RX_CNT]=res;             //¼ÇÂ¼½óêÕμ½μÄÖμ
                        RS485_RX_CNT++;                                              //½óêÕêy¾YÔö¼ó1
               }
      }
}
#endif

//3õê¼»ˉIO ′®¿ú2
//bound:2¨ìØÂê
void RS485_Init(u32 bound)
{
//GPIO¶Ë¿úéèÖÃ
      GPIO_InitTypeDef GPIO_Initure;

      PCF8574_Init();                      //3õê¼»ˉPCF8574￡¬óÃóú¿ØÖÆRE½Å

      __HAL_RCC_GPIOA_CLK_ENABLE();                      //ê1ÄüGPIOAê±Öó
      __HAL_RCC_USART2_CLK_ENABLE();                      //ê1ÄüUSART2ê±Öó

      GPIO_Initure.Pin=GPIO_PIN_2|GPIO_PIN_3; //PA2,3
      GPIO_Initure.Mode=GPIO_MODE_AF_PP;             //¸′óÃíÆíìêä3ö
      GPIO_Initure.Pull=GPIO_PULLUP;                      //éÏà-
      GPIO_Initure.Speed=GPIO_SPEED_HIGH;             //¸ßËù
      GPIO_Initure.Alternate=GPIO_AF7_USART2;       //¸′óÃÎaUSART2

      HAL_GPIO_Init(GPIOA,&GPIO_Initure);                //3õê¼»ˉPA2,3

//USART 3õê¼»ˉéèÖÃ
      USART2_RS485Handler.Instance=USART2;                               //USART2
      USART2_RS485Handler.Init.BaudRate=bound;                      //2¨ìØÂê
      USART2_RS485Handler.Init.WordLength=UART_WORDLENGTH_8B;       //×Ö3¤Îa8Î»êy¾Y¸ñê½
      USART2_RS485Handler.Init.StopBits=UART_STOPBITS_1;             //ò»¸öí￡Ö1Î»
      USART2_RS485Handler.Init.Parity=UART_PARITY_NONE;             //ÎTÆæÅ¼D￡ÑéÎ»
      USART2_RS485Handler.Init.HwFlowCtl=UART_HWCONTROL_NONE;       //ÎTó2¼tá÷¿Ø
      USART2_RS485Handler.Init.Mode=UART_MODE_TX_RX;                   //êÕ·￠Ä￡ê½
      HAL_UART_Init(&USART2_RS485Handler);                               //HAL_UART_Init()»áê1ÄüUSART2

  __HAL_UART_DISABLE_IT(&USART2_RS485Handler,UART_IT_TC);
#if EN_USART2_RX
      __HAL_UART_ENABLE_IT(&USART2_RS485Handler,UART_IT_RXNE);//¿aÆô½óêÕÖD¶Ï

      HAL_NVIC_EnableIRQ(USART2_IRQn);                                     //ê1ÄüUSART1ÖD¶Ï
      HAL_NVIC_SetPriority(USART2_IRQn,3,3);                               //ÇàÕ¼óÅÏè¼¶3￡¬×óóÅÏè¼¶3
#endif
  RS485_TX_Set(0);                                     //éèÖÃÎa½óêÕÄ￡ê½
}

//RS485·￠Ëílen¸ö×Ö½ú.
//buf:·￠ËíÇøê×μØÖ·
//len:·￠ËíμÄ×Ö½úêy(ÎaáËoí±¾′úÂëμÄ½óêÕÆ￥Åä,Õaàï½¨òé2»òa3¬1y64¸ö×Ö½ú)
void RS485_Send_Data(u8 *buf,u8 len)
{
      RS485_TX_Set(1);                      //éèÖÃÎa·￠ËíÄ￡ê½
      HAL_UART_Transmit(&USART2_RS485Handler,buf,len,500);
      RS485_RX_CNT=0;
      RS485_TX_Set(0);                      //éèÖÃÎa½óêÕÄ￡ê½
}
//RS4852éÑˉ½óêÕμ½μÄêy¾Y
//buf:½óêÕ»o′æê×μØÖ·
//len:¶áμ½μÄêy¾Y3¤¶è
void RS485_Receive_Data(u8 *buf,u8 *len)
{

      u8 rxlen=RS485_RX_CNT;
      u8 i=0;
      *len=0;                               //Ä¬èÏÎa0
      delay_ms(10);             //μè′y10ms,á¬Dø3¬1y10msÃ»óD½óêÕμ½ò»¸öêy¾Y,ÔòèÏÎa½óêÕ½áêø
      if(rxlen==RS485_RX_CNT&&rxlen)//½óêÕμ½áËêy¾Y,Çò½óêÕíê3éáË
      {
            for(i=0;i<rxlen;i++)
            {
                     buf=RS485_RX_BUF;
            }
            *len=RS485_RX_CNT;       //¼ÇÂ¼±¾′Îêy¾Y3¤¶è
            RS485_RX_CNT=0;             //Çåáã
      }
}
//RS485Ä￡ê½¿ØÖÆ.
//en:0,½óêÕ;1,·￠Ëí.
void RS485_TX_Set(u8 en)
{
      PCF8574_WriteBit(RS485_RE_IO,en);
}

主函数：
int main(void)
{
u8 key;
      u8 i=0,t=0;
      u8 cnt=0;
      u8 rs485buf[5];
HAL_Init();                   //3õê¼»ˉHAL¿a
Stm32_Clock_Init(360,25,2,8); //éèÖÃê±Öó,180Mhz
delay_init(180);             //3õê¼»ˉÑóê±oˉêy
uart_init(115200);             //3õê¼»ˉUSART
LED_Init();                   //3õê¼»ˉLED
KEY_Init();                   //3õê¼»ˉ°′¼ü
SDRAM_Init();                //3õê¼»ˉSDRAM
LCD_Init();                   //3õê¼»ˉLCD
            RS485_Init(2500000);                      //3õê¼»ˉRS485
      POINT_COLOR=RED;
      LCD_ShowString(30,50,200,16,16,"Apollo STM32F4/F7");
      LCD_ShowString(30,70,200,16,16,"RS485 TEST");
      LCD_ShowString(30,90,200,16,16,"ATOM@ALIENTEK");
      LCD_ShowString(30,110,200,16,16,"2016/1/16");
      LCD_ShowString(30,130,200,16,16,"KEY0:Send");
      POINT_COLOR=BLUE;
      LCD_ShowString(30,150,200,16,16,"Count:");                      //ÏÔê¾μ±Ç°¼ÆêyÖμ
      LCD_ShowString(30,170,200,16,16,"Send Data:");             //ìáê¾·￠ËíμÄêy¾Y
      LCD_ShowString(30,210,200,16,16,"Receive Data:");       //ìáê¾½óêÕμ½μÄêy¾Y

      while(1)
      {
               key=KEY_Scan(0);
               if(key==KEY0_PRES)  //KEY0°′ÏÂ,·￠Ëíò»′Îêy¾Y
               {
                        for(i=0;i<5;i++)

                              {
                              rs485buf=cnt+i;
                              LCD_ShowxNum(30+i*32,190,rs485buf,3,16,0X80);
                        }
                        RS485_Send_Data(rs485buf,5);
               }
               RS485_TX_Set(0);
               RS485_Receive_Data(rs485buf,&key);
               if(key)
               {
                        if(key>5)key=5;
                        for(i=0;i<key;i++)LCD_ShowxNum(30+i*32,230,rs485buf,3,16,0X80);
                  }
               t++;
               delay_ms(100);

               {
                     LED0=!LED0;
                     t=0;
                     cnt++;
                     LCD_ShowxNum(30+48,150,cnt,3,16,0X80);
               }
      }
}
图在另一个回复上