STM32-modbus rtu 之主机程序
考虑到modbus的使用场合大多为半双工而非全双工，所以，串口接收采用DMA+空闲中断，发送则直接发送。
#include "serial.h" #include "string.h" _serialbuf_st serialRXbuf_st; _serialbuf_st serialTXbuf_st; /*DMA接收数据缓存*/ u8 g_uart1DmaRXBuf[UART_DMARX_SIZE]; /* 说明：3个串口直接发送函数 编写：林 */ void myUSART_Sendbyte(USART_TypeDef* USARTx, uint16_t Data) { while((USARTx->SR&0X40)==0); USARTx->DR = (Data & (uint16_t)0x01FF); } void myUSART_Sendstr(USART_TypeDef* USARTx, const char *s) { while(*s != '\0') { myUSART_Sendbyte( USARTx, *s) ; s++; } } void myUSART_Sendarr(USART_TypeDef* USARTx, u8 a[] ,uint8_t len) { uint8_t i=0; while(i < len ) { myUSART_Sendbyte( USARTx, a[i]) ; i++; } } /* 说明： 串口1初始化 串口1使用DMA 接收 编写：林 */ void Usart1_init(u32 baud) { GPIO_InitTypeDef GPIO_InitStructure; USART_InitTypeDef USART_InitStructure; DMA_InitTypeDef DMA_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_USART1, ENABLE); RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 ; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_Init(GPIOA, &GPIO_InitStructure); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; GPIO_Init(GPIOA, &GPIO_InitStructure); USART_InitStructure.USART_BaudRate =baud;//一秒发送BaudRate个bit USART_InitStructure.USART_WordLength =USART_WordLength_8b; USART_InitStructure.USART_StopBits = USART_StopBits_1; USART_InitStructure.USART_Parity = USART_Parity_No; USART_InitStructure.USART_HardwareFlowControl =USART_HardwareFlowControl_None; USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; USART_Init(USART1, &USART_InitStructure); DMA_DeInit(DMA1_Channel5); DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&(USART1->DR)); DMA_InitStructure.DMA_MemoryBaseAddr = (u32)g_uart1DmaRXBuf; DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC; DMA_InitStructure.DMA_BufferSize = UART_DMARX_SIZE; DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte; DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh; DMA_InitStructure.DMA_M2M = DMA_M2M_Disable; DMA_Init(DMA1_Channel5,&DMA_InitStructure); USART_ITConfig(USART1,USART_IT_TC,DISABLE); USART_ITConfig(USART1,USART_IT_RXNE,DISABLE); USART_ITConfig(USART1,USART_IT_IDLE,ENABLE); NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; // NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; // NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; // NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; // NVIC_Init(&NVIC_InitStructure); USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE); USART_Cmd(USART1, ENABLE); DMA_Cmd(DMA1_Channel5,ENABLE); memset( & serialRXbuf_st ,0, sizeof ( serialRXbuf_st ) ) ; } //等待发送完成 void WaitForTransmitComplete(USART_TypeDef* USARTx) { while((USARTx->SR&0X40)==0){}; } /* 说明：串口中断，DMA与空闲中断处理，用于串口接收 编写：林 */ void USART1_IRQHandler(void) { _serialbuf_st *p= &serialRXbuf_st; __IO u8 temp = 0; u8 i=0; if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET) { temp = USART1->SR; temp = USART1->DR; DMA_Cmd(DMA1_Channel5,DISABLE); temp = UART_DMARX_SIZE - ((uint16_t)(DMA1_Channel5->CNDTR)); for (i = 0;i < temp;i++) { p->buf[i] =g_uart1DmaRXBuf[i]; } p->len = temp ; DMA_SetCurrDataCounter(DMA1_Channel5,UART_DMARX_SIZE); DMA_Cmd(DMA1_Channel5,ENABLE); } __nop(); } /*serial.h*/ #ifndef __SERIALx_H #define __SERIALx_H #include "stm32f10x.h" /*DMA接收数据缓存大小*/ #define UART_DMARX_SIZE 0xff typedef struct { u8 buf[UART_DMARX_SIZE]; __IO u8 len; } _serialbuf_st ; //串口数据结构 typedef struct { u8 addr;//从机地址 u8 start;//寄存器起始 u8 len; //接收到或待发送的寄存器数 u16 buf[UART_DMARX_SIZE/2];//寄存器数据 } _mbdata_st; //用户数据 extern _serialbuf_st serialRXbuf_st; extern _serialbuf_st serialTXbuf_st; void Usart1_init(u32 baud) ; void WaitForTransmitComplete(USART_TypeDef* USARTx) ; void myUSART_Sendbyte(USART_TypeDef* USARTx, uint16_t Data) ; void myUSART_Sendstr(USART_TypeDef* USARTx, const char *s) ; void myUSART_Sendarr(USART_TypeDef* USARTx, u8 a[] ,uint8_t len); #endif
首先实现发送函数
/* 说明： 接收“读保持寄存器”的结果 命令0X03 返回： res_OK 正确 res_ERR1 其他错误 res_ERR2 地址不符 res_ERR3 无反馈 */ u8 mb_recv_readHoldingReg( _mbdata_st *mbp) { u8 i; if( serialRXbuf_st.len == 0 ) return res_ERR3; serialRXbuf_st.len=0; if( mbp->addr == serialRXbuf_st.buf[0] ) { if( 0x03 == serialRXbuf_st.buf[1] ) { for(i=0;i<serialRXbuf_st.buf[2]/2;i++) { mbp->buf[mbp->start +i]= (u16)(serialRXbuf_st.buf[i*2+3]>>8) + serialRXbuf_st.buf[i*2+4]; } mbp->len = serialRXbuf_st.buf [2]/2;//寄存器数 return res_OK; } else { return res_ERR1; } } return res_ERR2; }
发送与接收代码如下
/* 发送"写保持寄存器"，命令0X10 */ void mb_sent_writeHoldingReg( const _mbdata_st mbp) { u8 i=0; u16 temp; u8 len = mbp.len; if(len>0x7d)len=0x7d; serialTXbuf_st.buf[0] = mbp.addr; serialTXbuf_st.buf[1] = 0x10; serialTXbuf_st.buf[2] = mbp.start>>8; serialTXbuf_st.buf[3] = mbp.start; serialTXbuf_st.buf[4] = 0; serialTXbuf_st.buf[5] = len; serialTXbuf_st.buf[6] = len*2; for(;i<mbp.len;i++) { serialTXbuf_st.buf[i*2+7] = mbp.buf[i]>>8; serialTXbuf_st.buf[i*2+8] = mbp.buf[i]; } temp=usMBCRC16( serialTXbuf_st.buf, len*2+7 ); serialTXbuf_st.buf[ len*2+7] = temp; //低 serialTXbuf_st.buf[ len*2+8] = temp>>8; myUSART_Sendarr( USART1, serialTXbuf_st.buf , len*2+9) ; WaitForTransmitComplete(USART1) ; //发送完成 } /* 说明： 接收“写保持寄存器”的从机反馈 返回： res_OK 正确 res_ERR1 校验错误 res_ERR2 返回格式错误 res_ERR3 无反馈 */ u8 mb_recv_writeHoldingReg( _mbdata_st *mbp ) { u8 i=0; if( serialRXbuf_st.len == 0 ) return res_ERR3; serialRXbuf_st.len=0; for(i=0;i<6;i++) { if ( serialTXbuf_st.buf[i] != serialRXbuf_st.buf[i] ) return res_ERR2; } if( serialRXbuf_st.buf[6] + (u16)(serialRXbuf_st.buf[7]<<8) != usMBCRC16( serialRXbuf_st.buf, 6 )) return res_ERR1; return res_OK; }
为了方便，将上面函数统一起来
u8 gmod = 0 ;//测试用，gmod=0，测试写保持寄存器功能，gmod=1读保持寄存器功能。 _mbdata_st HoldingReg_st = {1,0,5,{1,2,3,4,5,6,7,8,9}}; u8 gsync = 1 ; void mb_setMODRXorTX(bool RxorTx) { //此处需修改硬件，用于使用外部器件（比如485器件）的接收或发送。 } //统一发送 void smb_sentHoldingReg(const _mbdata_st mbp ) { mb_setMODRXorTX(1);//改为发送模式 if( gmod == 1 ) mb_sent_writeHoldingReg( HoldingReg_st); else mb_sent_readHoldingReg( HoldingReg_st ); mb_setMODRXorTX(0);//改为接收模式 gsync=1; } //统一接收 u8 smb_recvHoldingReg( _mbdata_st *mbp ) { u8 rel=0xff; if( 1 == gsync)//发送完成 { gsync=0; while( serialRXbuf_st.len == 0 ) { if(TIM3->CNT >4900) break ;//从机无响应 };//接收完成 if( gmod == 1) { rel=mb_recv_writeHoldingReg( &HoldingReg_st ) ; }else { rel=mb_recv_readHoldingReg( &HoldingReg_st ) ; } } return rel ; }在定时器服务里调用发送函数
void TIM3_IRQHandler(void) //TIM3中断 { if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //检查指定的TIM中断发生与否:TIM 中断源 { TIM_ClearITPendingBit(TIM3, TIM_IT_Update ); //清除TIMx的中断待处理位:TIM 中断源 { if(gmod == 1) HoldingReg_st.buf [1]++ ; //累增某个保持寄存器，用于测试观察 smb_sentHoldingReg( HoldingReg_st ) ; } } }在主循环里调用接收函数
while(1) { rel = smb_recvHoldingReg( &HoldingReg_st ) ; if( res_OK == rel && HoldingReg_st.buf[0] == 1 ) LED0=!LED0; //观察结果 }
程序烧录到STM32,，串口连接电脑，使用PC端从机软件 Modbus Slave 观察
F=0X03
F=0X10,(虽然显示03)
这个从机软件不能显示F=0X10也就是16，但功能是可以使用的。
不过这毕竟令人心里不爽，所以我使用nmodbus类库编写了C#上位机软件进行验证，如下图所示，可见F=16也就是0X10
