STM32-modbus rtu 之主機程序
一、STM32串口的發送與接收
考慮到modbus的使用場合大多爲半雙工而非全雙工，所以，串口接收採用DMA+空閒中斷，發送則直接發送。
/*serial.c*/
#include "serial.h"
#include "string.h"
_serialbuf_st serialRXbuf_st;
_serialbuf_st serialTXbuf_st;
/*DMA接收數據緩存*/
u8 g_uart1DmaRXBuf[UART_DMARX_SIZE];
/*
說明：3個串口直接發送函數
編寫：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++;
}
}
/*
說明：
串口1初始化
串口1使用DMA 接收
編寫：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;//一秒發送BaudRate個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 ) ) ;
}
/*等待發送完成*/
void WaitForTransmitComplete(USART_TypeDef* USARTx)
{
while((USARTx->SR&0X40)==0){};
}
/*
說明：串口中斷，DMA與空閒中斷處理，用於串口接收
編寫：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接收數據緩存大小*/
#define UART_DMARX_SIZE 0xff
typedef struct
{
u8 buf[UART_DMARX_SIZE];
__IO u8 len;
} _serialbuf_st ; //串口數據結構
typedef struct
{
u8 addr;//從機地址
u8 start;//寄存器起始
u8 len; //接收到或待發送的寄存器數
u16 buf[UART_DMARX_SIZE/2];//寄存器數據
} _mbdata_st; //用戶數據
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
二、實現讀保持寄存器功能：F=0x03
首先實現發送函數
/*
說明：
接收“讀保持寄存器”的結果
命令0X03
返回：
res_OK 正確
res_ERR1 其他錯誤
res_ERR2 地址不符
res_ERR3 無反饋
*/
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;//寄存器數
return res_OK;
}
else
{
return res_ERR1;
}
}
return res_ERR2;
}
三、實現寫保持寄存器功能：F=0X10
發送與接收代碼如下
/*
發送"寫保持寄存器"，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) ; //發送完成
}
/*
說明：
接收“寫保持寄存器”的從機反饋
返回：
res_OK 正確
res_ERR1 校驗錯誤
res_ERR2 返回格式錯誤
res_ERR3 無反饋
*/
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;
}
四、程序調用
爲了方便，將上面函數統一起來
//統一發送
void smb_sentHoldingReg(const _mbdata_st mbp )
{ mb_setMODRXorTX(1);//改爲發送模式
if( gmod == 1 )
mb_sent_writeHoldingReg( HoldingReg_st);
else
mb_sent_readHoldingReg( HoldingReg_st );
mb_setMODRXorTX(0);//改爲接收模式
gsync=1;
}
//統一接收
u8 smb_recvHoldingReg( _mbdata_st *mbp )
{
u8 rel=0xff;
if( 1 == gsync)//發送完成
{
gsync=0;
while( serialRXbuf_st.len == 0 )
{
if(TIM3->CNT >4900) break ;//從機無響應
};//接收完成
if( gmod == 1)
{
rel=mb_recv_writeHoldingReg( &HoldingReg_st ) ;
}else
{
rel=mb_recv_readHoldingReg( &HoldingReg_st ) ;
}
}
return rel ;
}
void TIM3_IRQHandler(void) //TIM3中斷
{
if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //檢查指定的TIM中斷髮生與否:TIM 中斷源
{
TIM_ClearITPendingBit(TIM3, TIM_IT_Update ); //清除TIMx的中斷待處理位:TIM 中斷源
{
if(gmod == 1) HoldingReg_st.buf [1]++ ; //累增某個保持寄存器，用於測試觀察
smb_sentHoldingReg( HoldingReg_st ) ;
}
}
}
while(1)
{
rel = smb_recvHoldingReg( &HoldingReg_st ) ;
if( res_OK == rel && HoldingReg_st.buf[0] == 1 ) LED0=!LED0; //觀察結果
}
五、驗證
程序燒錄到STM32,，串口連接電腦，使用PC端從機軟件 Modbus Slave 觀察F=0X03
F=0X10,(雖然顯示03)
這個從機軟件不能顯示F=0X10也就是16，但功能是可以使用的。
不過這畢竟令人心裏不爽，所以我使用nmodbus類庫編寫了C#上位機軟件進行驗證，如下圖所示，可見F=16也就是0X10
