STM32-modbus rtu 之主机程序
一、STM32串口的发送与接收
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。
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#include "serial.h"
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#include "string.h"
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_serialbuf_st serialRXbuf_st;
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_serialbuf_st serialTXbuf_st;
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/*DMA接收数据缓存*/
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u8 g_uart1DmaRXBuf[UART_DMARX_SIZE];
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/*
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说明：3个串口直接发送函数
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编写：林
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*/
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void myUSART_Sendbyte(USART_TypeDef* USARTx, uint16_t Data)
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{
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while((USARTx->SR&
0X40)==
0);
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USARTx->DR = (Data & (
uint16_t)
0x01FF);
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}
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void myUSART_Sendstr(USART_TypeDef* USARTx, const char *s)
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{
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while(*s !=
'\0')
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{
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myUSART_Sendbyte( USARTx, *s) ;
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s++;
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}
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}
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void myUSART_Sendarr(USART_TypeDef* USARTx, u8 a[] ,uint8_t len)
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{
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uint8_t i=
0;
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while(i < len )
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{
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myUSART_Sendbyte( USARTx, a[i]) ;
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i++;
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}
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}
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/*
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说明：
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串口1初始化
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串口1使用DMA 接收
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编写：林
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*/
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void Usart1_init(u32 baud)
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{
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GPIO_InitTypeDef GPIO_InitStructure;
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USART_InitTypeDef USART_InitStructure;
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DMA_InitTypeDef DMA_InitStructure;
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NVIC_InitTypeDef NVIC_InitStructure;
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RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_USART1, ENABLE);
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RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 ;
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GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
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GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
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GPIO_Init(GPIOA, &GPIO_InitStructure);
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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
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GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
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GPIO_Init(GPIOA, &GPIO_InitStructure);
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USART_InitStructure.USART_BaudRate =baud;
//一秒发送BaudRate个bit
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USART_InitStructure.USART_WordLength =USART_WordLength_8b;
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USART_InitStructure.USART_StopBits = USART_StopBits_1;
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USART_InitStructure.USART_Parity = USART_Parity_No;
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USART_InitStructure.USART_HardwareFlowControl =USART_HardwareFlowControl_None;
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USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
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USART_Init(USART1, &USART_InitStructure);
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DMA_DeInit(DMA1_Channel5);
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DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&(USART1->DR));
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DMA_InitStructure.DMA_MemoryBaseAddr = (u32)g_uart1DmaRXBuf;
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DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
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DMA_InitStructure.DMA_BufferSize = UART_DMARX_SIZE;
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DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
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DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
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DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
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DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
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DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
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DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
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DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
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DMA_Init(DMA1_Channel5,&DMA_InitStructure);
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USART_ITConfig(USART1,USART_IT_TC,DISABLE);
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USART_ITConfig(USART1,USART_IT_RXNE,DISABLE);
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USART_ITConfig(USART1,USART_IT_IDLE,ENABLE);
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NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
//
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NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority =
1;
//
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NVIC_InitStructure.NVIC_IRQChannelSubPriority =
1;
//
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NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
//
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NVIC_Init(&NVIC_InitStructure);
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USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);
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USART_Cmd(USART1, ENABLE);
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DMA_Cmd(DMA1_Channel5,ENABLE);
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memset( & serialRXbuf_st ,
0,
sizeof ( serialRXbuf_st ) ) ;
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}
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//等待发送完成
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void WaitForTransmitComplete(USART_TypeDef* USARTx)
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{
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while((USARTx->SR&
0X40)==
0){};
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}
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/*
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说明：串口中断，DMA与空闲中断处理，用于串口接收
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编写：林
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*/
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void USART1_IRQHandler(void)
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{
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_serialbuf_st *p= &serialRXbuf_st;
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__IO u8 temp =
0;
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u8 i=
0;
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if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET)
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{
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temp = USART1->SR;
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temp = USART1->DR;
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DMA_Cmd(DMA1_Channel5,DISABLE);
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temp = UART_DMARX_SIZE - ((
uint16_t)(DMA1_Channel5->CNDTR));
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for (i =
0;i < temp;i++)
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{
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p->buf[i] =g_uart1DmaRXBuf[i];
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}
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p->len = temp ;
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DMA_SetCurrDataCounter(DMA1_Channel5,UART_DMARX_SIZE);
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DMA_Cmd(DMA1_Channel5,ENABLE);
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}
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__nop();
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}
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/*serial.h*/
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#ifndef __SERIALx_H
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#define __SERIALx_H
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#include "stm32f10x.h"
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/*DMA接收数据缓存大小*/
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#define UART_DMARX_SIZE 0xff
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typedef
struct
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{
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u8 buf[UART_DMARX_SIZE];
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__IO u8 len;
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} _serialbuf_st ;
//串口数据结构
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typedef
struct
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{
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u8 addr;
//从机地址
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u8 start;
//寄存器起始
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u8 len;
//接收到或待发送的寄存器数
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u16 buf[UART_DMARX_SIZE/
2];
//寄存器数据
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} _mbdata_st;
//用户数据
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extern _serialbuf_st serialRXbuf_st;
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extern _serialbuf_st serialTXbuf_st;
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void Usart1_init(u32 baud) ;
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void WaitForTransmitComplete(USART_TypeDef* USARTx) ;
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void myUSART_Sendbyte(USART_TypeDef* USARTx, uint16_t Data) ;
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void myUSART_Sendstr(USART_TypeDef* USARTx, const char *s) ;
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void myUSART_Sendarr(USART_TypeDef* USARTx, u8 a[] ,uint8_t len);
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#endif
二、实现读保持寄存器功能：F=0x03
首先实现发送函数
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/*
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说明：
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接收“读保持寄存器”的结果
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命令0X03
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返回：
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res_OK 正确
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res_ERR1 其他错误
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res_ERR2 地址不符
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res_ERR3 无反馈
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*/
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u8 mb_recv_readHoldingReg( _mbdata_st *mbp)
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{
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u8 i;
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if( serialRXbuf_st.len ==
0 )
return res_ERR3;
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serialRXbuf_st.len=
0;
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if( mbp->addr == serialRXbuf_st.buf[
0] )
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{
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if(
0x03 == serialRXbuf_st.buf[
1] )
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{
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for(i=
0;i<serialRXbuf_st.buf[
2]/
2;i++)
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{
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mbp->buf[mbp->start +i]= (u16)(serialRXbuf_st.buf[i*
2+
3]>>
8) + serialRXbuf_st.buf[i*
2+
4];
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}
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mbp->len = serialRXbuf_st.buf [
2]/
2;
//寄存器数
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return res_OK;
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}
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else
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{
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return res_ERR1;
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}
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}
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return res_ERR2;
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}
三、实现写保持寄存器功能：F=0X10
发送与接收代码如下
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/*
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发送"写保持寄存器"，命令0X10
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*/
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void mb_sent_writeHoldingReg( const _mbdata_st mbp)
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{
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u8 i=
0;
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u16 temp;
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u8 len = mbp.len;
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if(len>
0x7d)len=
0x7d;
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serialTXbuf_st.buf[
0] = mbp.addr;
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serialTXbuf_st.buf[
1] =
0x10;
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serialTXbuf_st.buf[
2] = mbp.start>>
8;
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serialTXbuf_st.buf[
3] = mbp.start;
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serialTXbuf_st.buf[
4] =
0;
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serialTXbuf_st.buf[
5] = len;
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serialTXbuf_st.buf[
6] = len*
2;
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for(;i<mbp.len;i++)
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{
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serialTXbuf_st.buf[i*
2+
7] = mbp.buf[i]>>
8;
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serialTXbuf_st.buf[i*
2+
8] = mbp.buf[i];
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}
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temp=usMBCRC16( serialTXbuf_st.buf, len*
2+
7 );
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serialTXbuf_st.buf[ len*
2+
7] = temp;
//低
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serialTXbuf_st.buf[ len*
2+
8] = temp>>
8;
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myUSART_Sendarr( USART1, serialTXbuf_st.buf , len*
2+
9) ;
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WaitForTransmitComplete(USART1) ;
//发送完成
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}
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/*
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说明：
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接收“写保持寄存器”的从机反馈
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返回：
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res_OK 正确
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res_ERR1 校验错误
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res_ERR2 返回格式错误
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res_ERR3 无反馈
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*/
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u8 mb_recv_writeHoldingReg( _mbdata_st *mbp )
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{
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u8 i=
0;
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if( serialRXbuf_st.len ==
0 )
return res_ERR3;
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serialRXbuf_st.len=
0;
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for(i=
0;i<
6;i++)
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{
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if ( serialTXbuf_st.buf[i] != serialRXbuf_st.buf[i] )
return res_ERR2;
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}
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if( serialRXbuf_st.buf[
6] + (u16)(serialRXbuf_st.buf[
7]<<
8) != usMBCRC16( serialRXbuf_st.buf,
6 ))
return res_ERR1;
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return res_OK;
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}
四、程序调用
为了方便，将上面函数统一起来
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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。
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_mbdata_st HoldingReg_st = {
1,
0,
5,{
1,
2,
3,
4,
5,
6,
7,
8,
9}};
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u8 gsync =
1 ;
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void mb_setMODRXorTX(bool RxorTx)
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{
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//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。
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}
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//统一发送
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void smb_sentHoldingReg(const _mbdata_st mbp )
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{ mb_setMODRXorTX(
1);
//改为发送模式
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if( gmod ==
1 )
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mb_sent_writeHoldingReg( HoldingReg_st);
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else
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mb_sent_readHoldingReg( HoldingReg_st );
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mb_setMODRXorTX(
0);
//改为接收模式
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gsync=
1;
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}
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//统一接收
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u8 smb_recvHoldingReg( _mbdata_st *mbp )
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{
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u8 rel=
0xff;
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if(
1 == gsync)
//发送完成
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{
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gsync=
0;
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while( serialRXbuf_st.len ==
0 )
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{
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if(TIM3->CNT >
4900)
break ;
//从机无响应
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};
//接收完成
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if( gmod ==
1)
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{
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rel=mb_recv_writeHoldingReg( &HoldingReg_st ) ;
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}
else
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{
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rel=mb_recv_readHoldingReg( &HoldingReg_st ) ;
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}
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}
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return rel ;
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}
在定时器服务里调用发送函数
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void TIM3_IRQHandler(void) //TIM3中断
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{
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if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
//检查指定的TIM中断发生与否:TIM 中断源
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{
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TIM_ClearITPendingBit(TIM3, TIM_IT_Update );
//清除TIMx的中断待处理位:TIM 中断源
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{
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if(gmod ==
1) HoldingReg_st.buf [
1]++ ;
//累增某个保持寄存器，用于测试观察
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smb_sentHoldingReg( HoldingReg_st ) ;
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}
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}
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}
在主循环里调用接收函数
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while(
1)
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{
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rel = smb_recvHoldingReg( &HoldingReg_st ) ;
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if( res_OK == rel && HoldingReg_st.buf[
0] ==
1 ) LED0=!LED0;
//观察结果
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}
五、验证
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
转载：https://blog.csdn.net/wangzibigan/article/details/77722939
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