Freemodbus通信，串口接收模式改为DMA接收模式

1万 · 2020-2-11 10:45

Freemodbus通信，串口接收模式改为DMA接收模式

1万 · 2020-2-11 10:48

在实际项目开发中，当使用Freemodbus从机协议栈时，会遇到一个问题，就是网上大多数对于该协议栈的移植，在数据接收这块，使用的大都是串口中断接收模式。这样做会有一个问题，如果一条Modbus总线上有若干个从机，一个个从机接收到主机的数据请求时，返回的数据长度大于1kBytes，会有一个问题，总线上其他的从机都处于串口中断接收模式，这样的话，在这段时间内，其他的从机是处于忙碌状态。可想而知对于MCU的CPU是一种浪费。那么对于现在网上大家常用的stm32，大家在实际项目中，都有可能用到Modbus通信协议，要么是自己写，要么是移植人家的。我在实际项目总，为了省事，直接移植人家的freemodbus，做从机协议栈来使用。但是对它的数据接收模式做了一些修改，具体修改看下文代码。

1万 · 2020-2-11 10:49

posterial.c文件:该文件实现对串口的底层配置和发送实现
~~~
/*
* FreeModbus Libary: STM32 Port
* Copyright (C) 2013 Armink <armink.ztl@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*
* File: $Id: portserial.c,v 1.60 2013/08/13 15:07:05 Armink $
*/

/* ----------------------- Platform includes --------------------------------*/
#include "port.h"

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"

/* ----------------------- static functions ---------------------------------*/
static void prvvUARTTxReadyISR(void);
//static void prvvUARTRxISR(void);

/* -------------------------- golobal function ------------------------------*/
unsigned char * exportPoint(unsigned short * length);
void  MB_DMAchannelInit (void);

extern volatile UCHAR  ucRTUBuf[7*1024];

1万 · 2020-2-11 10:50

/* ----------------------- Start implementation -----------------------------*/
void vMBPortSerialEnable(BOOL xRxEnable, BOOL xTxEnable)
{

if (xRxEnable)
{
//USART_ITConfig(MODBUS_RS485_SERIAL_PORT, USART_IT_RXNE, ENABLE);
SLAVE_RS485_RECEIVE_MODE;
}
else
{
SLAVE_RS485_SEND_MODE;
//USART_ITConfig(MODBUS_RS485_SERIAL_PORT, USART_IT_RXNE, DISABLE);
}
if (xTxEnable)
{
USART_ITConfig(MODBUS_RS485_SERIAL_PORT, USART_IT_TXE, ENABLE);
}
else
{
USART_ITConfig(MODBUS_RS485_SERIAL_PORT, USART_IT_TXE, DISABLE);
}
}

1万 · 2020-2-11 10:50

void vMBPortClose(void)
{
USART_ITConfig(MODBUS_RS485_SERIAL_PORT, USART_IT_TXE | USART_IT_RXNE, DISABLE);
USART_Cmd(MODBUS_RS485_SERIAL_PORT, DISABLE);
}

1万 · 2020-2-11 10:51

/* 默认一个从机串口3 波特率可设置  奇偶检验可设置. */
BOOL
xMBPortSerialInit(UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits,
eMBParity eParity)
{
OS_CPU_SR  cpu_sr;

GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

/* -------------------时钟初始化------------------------------------. */
//RCC_APB2PeriphClockCmd(MODBUS_RS485_CONTRL_RCC, ENABLE);
RCC_APB2PeriphClockCmd(MODBUS_PORT_SERIAL_RCC |
            MODBUS_RS485_CONTRL_RCC, ENABLE);

/* -----------------------IO初始化---------------------------------. */

/* USART1_TX -----.*/
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Pin = MODBUS_PORT_SERIAL_TX_PIN;
GPIO_Init(MODBUS_PORT_SERIAL_TX_GPIO,&GPIO_InitStructure);

/* USART1_RX------.*/
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Pin = MODBUS_PORT_SERIAL_RX_PIN;
GPIO_Init(MODBUS_PORT_SERIAL_RX_GPIO, &GPIO_InitStructure);

/* 配置485发送和接收模----------.*/
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Pin = MODBUS_RS485_CONTRL_PIN;
GPIO_Init(MODBUS_RS485_CONTRL_GPIO, &GPIO_InitStructure);


/* 串口初始化 ---------------. */
USART_InitStructure.USART_BaudRate = ulBaudRate;

switch (eParity)
{
case MB_PAR_NONE:
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
break;

case MB_PAR_ODD:
USART_InitStructure.USART_Parity = USART_Parity_Odd;
USART_InitStructure.USART_WordLength = USART_WordLength_9b;
break;

case MB_PAR_EVEN:
USART_InitStructure.USART_Parity = USART_Parity_Even;
USART_InitStructure.USART_WordLength = USART_WordLength_9b;
break;

default:
return FALSE;
}

USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_HardwareFlowControl =
USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

if (ucPORT != 1)
return FALSE;

OS_ENTER_CRITICAL();

USART_Init(MODBUS_RS485_SERIAL_PORT, &USART_InitStructure);
//USART_ITConfig(MODBUS_RS485_SERIAL_PORT, USART_IT_RXNE, ENABLE);
USART_Cmd(MODBUS_RS485_SERIAL_PORT, ENABLE);
USART_ClearFlag(MODBUS_RS485_SERIAL_PORT,USART_FLAG_TC);
USART_DMACmd(MODBUS_RS485_SERIAL_PORT,USART_DMAReq_Rx,ENABLE);


/* ------------------中断初始化-----------------------------
*设置NVIC优先级分组为Group2：0-3抢占式优先级，0-3的响应式优先级
-----------------------------------------------------------. */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
NVIC_InitStructure.NVIC_IRQChannel = MB_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

OS_EXIT_CRITICAL();

MB_DMAchannelInit();

return TRUE;
}

1万 · 2020-2-11 10:51

BOOL xMBPortSerialPutByte(CHAR ucByte)
{
USART_SendData(MODBUS_RS485_SERIAL_PORT, ucByte);
/* add by frank 2019 -3-11. */
while(USART_GetFlagStatus(MODBUS_RS485_SERIAL_PORT, USART_FLAG_TC) == RESET){};
return TRUE;
}

1万 · 2020-2-11 10:51

BOOL xMBPortSerialGetByte(CHAR * pucByte)
{
*pucByte = USART_ReceiveData(MODBUS_RS485_SERIAL_PORT);
return TRUE;
}

1万 · 2020-2-11 10:52

/*
* Create an interrupt handler for the transmit buffer empty interrupt
* (or an equivalent) for your target processor. This function should then
* call pxMBFrameCBTransmitterEmpty( ) which tells the protocol stack that
* a new character can be sent. The protocol stack will then call
* xMBPortSerialPutByte( ) to send the character.
*/
void prvvUARTTxReadyISR(void)
{
pxMBFrameCBTransmitterEmpty();
}

1万 · 2020-2-11 10:55

/*
* Create an interrupt handler for the receive interrupt for your target
* processor. This function should then call pxMBFrameCBByteReceived( ). The
* protocol stack will then call xMBPortSerialGetByte( ) to retrieve the
* character.
*/
//void prvvUARTRxISR(void)
//{
// //pxMBFrameCBByteReceived();
//}

void MB_IRQHandler(void)
{
OS_CPU_SR cpu_sr;

OS_ENTER_CRITICAL();

/* 发送中断. */
if (USART_GetITStatus(MODBUS_RS485_SERIAL_PORT, USART_IT_TXE) == SET)
{
prvvUARTTxReadyISR();
}

OS_EXIT_CRITICAL();
}

1万 · 2020-2-11 10:55

////////////////////////////////////////////////////////////////////////////////
//函数名称:MB_DMAchannelInit
//功能描述：初始化DMA接收通道
//入口参数：无
//出口参数：无
////////////////////////////////////////////////////////////////////////////////
void  MB_DMAchannelInit (void)
{
DMA_InitTypeDef DMA_InitStructure;
static unsigned char  *ptraddress;
unsigned short length = 0;

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
DMA_DeInit(DMA1_Channel5);
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)(&USART1->DR);
DMA_InitStructure.DMA_MemoryBaseAddr    = (uint32_t)(exportPoint(&length));

DMA_InitStructure.DMA_DIR    = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize =length;

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);
DMA_Cmd(DMA1_Channel5, ENABLE);

}

1万 · 2020-2-11 10:56

porttimer.c：该文件实现对定时器的相关配置和增加定时器中断函数//发送还是使用空中断触发方式
/*
* FreeModbus Libary: STM32 Port
* Copyright (C) 2013 Armink <armink.ztl@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* File: $Id: porttimer.c,v 1.60 2013/08/13 15:07:05 Armink $
*/

/* ----------------------- Osal includes ------------------------------------*/
#include "includes.h"

/* ----------------------- Platform includes --------------------------------*/
#include "port.h"

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"

/* ----------------------- static functions ---------------------------------*/
static void prvvTIMERExpiredISR(void);

1万 · 2020-2-11 10:56

/* ----------------------- Start implementation -----------------------------*/
BOOL xMBPortTimersInit(USHORT usTim1Timerout50us)
{

uint16_t PrescalerValue = 0;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
NVIC_InitTypeDef NVIC_InitStructure;
//====================================时钟初始化===========================
//使能定时器3时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
//====================================定时器初始化===========================
//定时器时间基配置说明
//HCLK为72MHz，APB1经过2分频为36MHz
//TIM3的时钟倍频后为72MHz（硬件自动倍频,达到最大）
//TIM3的分频系数为3599，时间基频率为72 / (1 + Prescaler) = 20KHz,基准为50us
//TIM最大计数值为usTim1Timerout50u

PrescalerValue = (uint16_t) (SystemCoreClock / 20000) - 1;
//定时器1初始化
TIM_TimeBaseStructure.TIM_Period = (uint16_t) usTim1Timerout50us;
TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
//预装载使能
TIM_ARRPreloadConfig(TIM3, ENABLE);
//====================================中断初始化=============================
//设置NVIC优先级分组为Group2：0-3抢占式优先级，0-3的响应式优先级
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
//清除溢出中断标志位
TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
//定时器3溢出中断关闭
TIM_ITConfig(TIM3, TIM_IT_Update, DISABLE);
//定时器3禁能
TIM_Cmd(TIM3, DISABLE);
return TRUE;
//((1+TIM_Prescaler )/72M)*(1+TIM_Period )

}

1万 · 2020-2-11 10:57

void vMBPortTimersEnable()
{
TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);
TIM_SetCounter(TIM3, 0);
TIM_Cmd(TIM3, ENABLE);
}

1万 · 2020-2-11 10:57

void vMBPortTimersDisable()
{
TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
TIM_ITConfig(TIM3, TIM_IT_Update, DISABLE);
TIM_SetCounter(TIM3, 0);
TIM_Cmd(TIM3, DISABLE);
}

1万 · 2020-2-11 10:57

void prvvTIMERExpiredISR(void)
{
(void) pxMBPortCBTimerExpired();
}

1万 · 2020-2-11 10:57

void TIM3_IRQHandler(void)
{
OS_CPU_SR cpu_sr;

// ENTER_CRITICAL_SECTION();
OS_ENTER_CRITICAL( );
if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
{

TIM_ClearFlag(TIM3, TIM_FLAG_Update); //清中断标记
TIM_ClearITPendingBit(TIM3, TIM_IT_Update); //清除定时器T3溢出中断标志位
prvvTIMERExpiredISR();
}
// EXIT_CRITICAL_SECTION( );
OS_EXIT_CRITICAL( );
}

1万 · 2020-2-11 10:58

mbrtu.c：实现数据的接收解析和数据发送

1万 · 2020-2-11 10:58

/*
* FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
* Copyright (c) 2006-2018 Christian Walter <cwalter@embedded-solutions.at>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/

/* ----------------------- Osal includes ------------------------------------*/
#include "includes.h"
/* ----------------------- System includes ----------------------------------*/
#include "stdlib.h"
#include "string.h"

/* ----------------------- Platform includes --------------------------------*/
#include "port.h"

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbrtu.h"
#include "mbframe.h"

#include "mbcrc.h"
#include "mbport.h"

/* ----------------------- task includes -------------------------------------*/
#include "app_task.h"

/* ----------------------- Defines ------------------------------------------*/
#define MB_SER_PDU_SIZE_MIN    4    /*!< Minimum size of a Modbus RTU frame. */
#define MB_SER_PDU_SIZE_MAX (7 *1024)    /*!< Maximum size of a Modbus RTU frame. */
#define MB_SER_PDU_SIZE_CRC    2    /*!< Size of CRC field in PDU. */
#define MB_SER_PDU_ADDR_OFF    0    /*!< Offset of slave address in Ser-PDU. */
#define MB_SER_PDU_PDU_OFF    1    /*!< Offset of Modbus-PDU in Ser-PDU. */

/* ----------------------- Type definitions ---------------------------------*/
typedef enum
{
STATE_RX_INIT,             /*!< Receiver is in initial state. */
STATE_RX_IDLE,             /*!< Receiver is in idle state. */
STATE_RX_RCV,             /*!< Frame is beeing received. */
STATE_RX_ERROR             /*!< If the frame is invalid. */
} eMBRcvState;

typedef enum
{
STATE_TX_IDLE,             /*!< Transmitter is in idle state. */
STATE_TX_XMIT             /*!< Transmitter is in transfer state. */
} eMBSndState;

/* ----------------------- Static variables ---------------------------------*/
static volatile eMBSndState eSndState;
static volatile eMBRcvState eRcvState;

/* ------------------------USART SEND BUFFER ---------------------------------*/
volatile UCHAR  ucRTUBuf[MB_SER_PDU_SIZE_MAX];

static volatile UCHAR *pucSndBufferCur;
static volatile USHORT usSndBufferCount;

static volatile USHORT usRcvBufferPos;

/*--------------------------- Golobal functions ------------------------------*/
void  MB_DMAchannelInit (void);

1万 · 2020-2-11 10:58

/* ----------------------- Start implementation -----------------------------*/
eMBErrorCode
eMBRTUInit( UCHAR ucSlaveAddress, UCHAR ucPort, ULONG ulBaudRate, eMBParity eParity )
{
eMBErrorCode eStatus = MB_ENOERR;
ULONG          usTimerT35_50us;
OS_CPU_SR    cpu_sr;
( void )ucSlaveAddress;
// ENTER_CRITICAL_SECTION(  );
OS_ENTER_CRITICAL( );

/* Modbus RTU uses 8 Databits. */
if( xMBPortSerialInit( ucPort, ulBaudRate, 8, eParity ) != TRUE )
{
      eStatus = MB_EPORTERR;
}
else
{
      /* - 修改为固定100  则定时5ms一次中断. */
      usTimerT35_50us = 100;
      if( xMBPortTimersInit( ( USHORT ) usTimerT35_50us ) != TRUE )
      {
         eStatus = MB_EPORTERR;
      }
}
// EXIT_CRITICAL_SECTION(  );
OS_EXIT_CRITICAL( );
return eStatus;
}