STM32 ——使用多任务框架RT-thread Nano完成modbus接口的温湿度Slave设备

---

实验环境

FreeMODBUS
ModbusPoll
STM32F103C8T6
杜邦线
DHT20温湿度模块

Modbus原理以及简单应用：使用c语言完成modbus协议，从云端服务器读取温湿度信息

FreeModbus 的详细介绍可以看 FreeMosbus 官网：FreeMODBUS

STM32移植RT_Thread：STM32 —— RT-Thread Nano 移植

AHT20驱动代码文件：https://pan.baidu.com/s/1hDdyDftfJs6PshESHmHgFQ?pwd=8888
提取码：8888

一、FreeModbus 协议简介

目前，FreeModbus最新版本是V1.6，可以通过官网下载，链接如下：
https://www.embedded-solutions.at/en/freemodbus-downloads/

FreeMODBUS 是一个奥地利人写的 Modbus 协议,它是一个针对嵌入式应用的一个免费（自由）的通用 MODBUS 协议的移植。Modbus 是一个工业制造环境中应用的一个通用协议。Modbus 通信协议栈包括两层：Modbus 应用层协议，该层定义了数据模式和功能；另外一层是网络层

FreeMODBUS 提供了 RTU/ASCII 传输模式及 TCP 协议支持。FreeModbus 遵循 BSD 许可证，这意味着用户可以将 FreeModbus 应用于商业环境中。下面给出命令表：

指令代码	描述	是否支持	备注
Master	主机	否
Slave	从机	是
MB_RTU	RTU模式	是
MB_ASCII	ASCII模式	是
MB_TCP	TCP模式	是
0x01	读线圈	是
0x02	读离散输入	是
0x03	读保持寄存器	是
0x04	读输入寄存器	是
0x05	写单个线圈	是
0x06	写单个寄存器	是
0x07	读异常状态	否
0x08	诊断	否	否
0x0B	获取事件计数器	否
0x0C	获取事件记录	否
0x0F	写多个线圈	是
0x10	写多个寄存器	是
0x11	报告从机ID	是	协议与文档不一致
0x14	读文件记录	否
0x15	写文件记录	否
0x16	屏蔽写寄存器	否
0x17	读/写多个寄存器	是
0x18	写FIFO	否
0x2B	封装接口传输	否
0x2B/0x0D	CANopen参考请求于应答	否
0x2B/0x0E	读设备身份表示	否

二、使用HAL库移植FreeModbus 驱动

（1）FreeModbus 驱动移植准备阶段

首先要下载 FreeModbus 协议，我们这里要安装的是从机程序，下载连接会放在文末，然后将我们下载好的压缩包解压出来，解压后文件夹内容如下：

然后我们进入到 demo 目录下，新建一个STM32MB 用于存储适用于我们的最小系统开发板的 FreeMosbus 驱动文件

将 demo/BARE 目录下的所有文件复制到我们刚才新建的文件夹下，然后再将 demo 目录下的 modbus 文件加复制到我们刚创建的目录下，这样我们就已经准备好了 Modbus 驱动环境：

（2）CubeMX 基本项目配置

1. RCC 配置
   

2. USART1 配置
   

3. TIM3 配置
   

4. I2C 配置
   

5. SYS 配置
   

（3）RT-Thread 配置

1. 点击 Softwares Packages->Select Components，进入组件配置界面
   
2. 选择 RealThread， 然后根3.1.5版本的，然后点击 OK 按钮
   
3. 这时会新增Software Packs展开就可以看见添加的RealThread.RT_Thread,勾选相应内容
   
4. NVIC 配置
   
5. 时钟配置
   
6. 引脚配置
   
7. 创建项目
   
   

三、引入驱动代码文件并添加头文件路径

1. 首先我们需要将对应的所有驱动文件复制到我们的项目目录下：
   
   这两个文件都在上述提到过并给出，请仔细阅读

2. 创建MD，MD_Port以及AHT20文件目录，引入对应文件
   这里 MD中添加我们 STM32MB/modbus 中的所有文件，Modbus_Port 中添加我们 STM32MB/port 中的所有文件以及demo.c文件
   
   
   
   

3. 最后添加头文件目录：
   

四、修改工程源码

（1）修改 FreeModbus 代码

1. 修改 portserial.c 的代码
   引入相关头文件

#include "usart.h"

修改 vMBPortSerialEnable 函数，该函数用于串口的接收和发送功能的打开或关闭

修改后代码如下：

void vMBPortSerialEnable( BOOL xRxEnable, BOOL xTxEnable )	第一个参数为串口的接收功能的打开与关闭，第二个参数为串口的发送功能的打开与关闭
{
    
    
    /* If xRXEnable enable serial receive interrupts. If xTxENable enable
     * transmitter empty interrupts.
     */
	
	if (xRxEnable)	//将串口收发中断和modbus联系起来，下面的串口改为自己使能的串口
	{
    
    
		__HAL_UART_ENABLE_IT(&huart1,UART_IT_RXNE);	//我用的是串口1，故为&huart1
	}
	else
	{
    
    
		__HAL_UART_DISABLE_IT(&huart1,UART_IT_RXNE);
	}
	if (xTxEnable)
	{
    
    
		__HAL_UART_ENABLE_IT(&huart1,UART_IT_TXE);
	}
	else
	{
    
    
		__HAL_UART_DISABLE_IT(&huart1,UART_IT_TXE);
	}
}

修改 xMBPortSerialInit 函数，该函数对 UART 串口进行初始化，由 eMBRTUInit 函数进行调用，这里改为默认返回 TRUE

修改后代码如下：

BOOL xMBPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity )
{
    
    
    return TRUE;
}

修改 xMBPortSerialPutByte 和 xMBPortSerialGetByte 函数，串口发送和接收函数，将STM32串口发送函数进行封装，供协议栈使用

修改后代码如下：

BOOL xMBPortSerialPutByte( CHAR ucByte )
{
    
    
    /* Put a byte in the UARTs transmit buffer. This function is called
     * by the protocol stack if pxMBFrameCBTransmitterEmpty( ) has been
     * called. */
	if(HAL_UART_Transmit(&huart1,(uint8_t *)&ucByte,1,0x01) != HAL_OK){
    
    
			return FALSE;
	}
	else {
    
    
		return TRUE;
	}
}

BOOL xMBPortSerialGetByte( CHAR * pucByte )
{
    
    
    /* Return the byte in the UARTs receive buffer. This function is called
     * by the protocol stack after pxMBFrameCBByteReceived( ) has been called.
     */
	if(HAL_UART_Receive (&huart1 ,(uint8_t *)pucByte,1,0x01) != HAL_OK )//添加接收一位代码
		return FALSE ;
	else {
    
    
		return TRUE;
	}
}

修改 prvvUARTTxReadyISR 和 prvvUARTRxISR 函数，总线状态改为发送后，会在发送缓冲时，自动调用 prvvUARTTxReadyISR() 中断服务程序。prvvUARTTxReadyISR() 只调用了一个函数，就是 pxMBFrameCBTransmitterEmpty ()

数据链路层是最基本的打包部分，将数据打包成帧，送到应用层。在数据链路层协议中，使用中断方式来接受。那么每次接收到字符就自动调用接收字符的 ISR 程序。按照规定，应该将中断服务程序安装给 prvvUARTRxISR(void) 函数。实际上这个函数只调用了一个函数：

pxMBFrameCBByteReceived()，这个指针调用了 xMBRTUReceiveFSM 函数。

将两个函数前的 static 去掉即可，修改后代码如下：

void prvvUARTTxReadyISR( void )
{
    
    
    pxMBFrameCBTransmitterEmpty(  );
}

void prvvUARTRxISR( void )
{
    
    
    pxMBFrameCBByteReceived(  );
}

2. 完整 portserial.c 代码如下：

/*
 * FreeModbus Libary: BARE Port
 * Copyright (C) 2006 Christian Walter <[email protected]>
 *
 * 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: $Id$
 */

#include "port.h"

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

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

/* ----------------------- Start implementation -----------------------------*/
void vMBPortSerialEnable( BOOL xRxEnable, BOOL xTxEnable )
{
    
    
    /* If xRXEnable enable serial receive interrupts. If xTxENable enable
     * transmitter empty interrupts.
     */
	
	if (xRxEnable)															//将串口收发中断和modbus联系起来，下面的串口改为自己使能的串口
	{
    
    
		__HAL_UART_ENABLE_IT(&huart1,UART_IT_RXNE);	//我用的是串口1，故为&huart1
	}
	else
	{
    
    
		__HAL_UART_DISABLE_IT(&huart1,UART_IT_RXNE);
	}
	if (xTxEnable)
	{
    
    
		__HAL_UART_ENABLE_IT(&huart1,UART_IT_TXE);
	}
	else
	{
    
    
		__HAL_UART_DISABLE_IT(&huart1,UART_IT_TXE);
	}
}

BOOL xMBPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity )
{
    
    
    return TRUE;
}

BOOL xMBPortSerialPutByte( CHAR ucByte )
{
    
    
    /* Put a byte in the UARTs transmit buffer. This function is called
     * by the protocol stack if pxMBFrameCBTransmitterEmpty( ) has been
     * called. */
	if(HAL_UART_Transmit(&huart1,(uint8_t *)&ucByte,1,0x01) != HAL_OK){
    
    
			return FALSE;
	}
	else {
    
    
		return TRUE;
	}
}

BOOL xMBPortSerialGetByte( CHAR * pucByte )
{
    
    
    /* Return the byte in the UARTs receive buffer. This function is called
     * by the protocol stack after pxMBFrameCBByteReceived( ) has been called.
     */
	if(HAL_UART_Receive (&huart1 ,(uint8_t *)pucByte,1,0x01) != HAL_OK )//添加接收一位代码
		return FALSE ;
	else {
    
    
		return TRUE;
	}
}

/* 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(  );
}

/* 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(  );
}

3. 修改 porttimer.c 的代码

/*
 * FreeModbus Libary: BARE Port
 * Copyright (C) 2006 Christian Walter <[email protected]>
 *
 * 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: $Id$
 */

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

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

#include "stm32f1xx_hal.h"
#include "tim.h"

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

/* ----------------------- Start implementation -----------------------------*/
BOOL xMBPortTimersInit( USHORT usTim1Timerout50us )
{
    
    
    return TRUE;
}


inline void vMBPortTimersEnable(  )
{
    
    
    /* Enable the timer with the timeout passed to xMBPortTimersInit( ) */
	__HAL_TIM_CLEAR_IT(&htim3,TIM_IT_UPDATE);
	__HAL_TIM_ENABLE_IT(&htim3,TIM_IT_UPDATE);
	__HAL_TIM_SET_COUNTER(&htim3,0);
	__HAL_TIM_ENABLE(&htim3);
}

inline void vMBPortTimersDisable(  )	//取消定时器中断
{
    
    
    /* Disable any pending timers. */
	__HAL_TIM_DISABLE(&htim3);
	__HAL_TIM_SET_COUNTER(&htim3,0);
	__HAL_TIM_DISABLE_IT(&htim3,TIM_IT_UPDATE);
	__HAL_TIM_CLEAR_IT(&htim3,TIM_IT_UPDATE);
}

/* Create an ISR which is called whenever the timer has expired. This function
 * must then call pxMBPortCBTimerExpired( ) to notify the protocol stack that
 * the timer has expired.
 */
void prvvTIMERExpiredISR( void )
{
    
    
    ( void )pxMBPortCBTimerExpired(  );
}

4. 修改 port.h 的代码

/*
 * FreeModbus Libary: BARE Port
 * Copyright (C) 2006 Christian Walter <[email protected]>
 *
 * 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: $Id$
 */

#ifndef _PORT_H
#define _PORT_H

#include <assert.h>
#include <inttypes.h>
#include "stm32f1xx_hal.h"

#define	INLINE                      inline
#define PR_BEGIN_EXTERN_C           extern "C" {
      
      
#define	PR_END_EXTERN_C             }

#define ENTER_CRITICAL_SECTION( )		__set_PRIMASK(1)	// 关闭总中断
#define EXIT_CRITICAL_SECTION( )		__set_PRIMASK(0)	// 开启总中断
typedef uint8_t BOOL;

typedef unsigned char UCHAR;
typedef char CHAR;

typedef uint16_t USHORT;
typedef int16_t SHORT;

typedef uint32_t ULONG;
typedef int32_t LONG;

#ifndef TRUE
#define TRUE            1
#endif

#ifndef FALSE
#define FALSE           0
#endif

#endif

5. 修改 stm32f1xx_it.c 的代码
   调用如下全局函数：

extern void prvvUARTTxReadyISR(void);
extern void prvvUARTRxISR(void);
extern void prvvTIMERExpiredISR( void );
用于 DMA 与 I2C 中断设置
extern DMA_HandleTypeDef hdma_i2c1_rx;
extern DMA_HandleTypeDef hdma_i2c1_tx;
extern I2C_HandleTypeDef hi2c1;

修改 USART1_IRQHandler 函数，用于 USART 串口 1 处理中断

修改后代码如下：

void USART1_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN USART1_IRQn 0 */

  /* USER CODE END USART1_IRQn 0 */
  HAL_UART_IRQHandler(&huart1);
  /* USER CODE BEGIN USART1_IRQn 1 */
	if(__HAL_UART_GET_IT_SOURCE(&huart1, UART_IT_RXNE)!= RESET) 
	{
    
    
		prvvUARTRxISR();//接收中断
	}

	if(__HAL_UART_GET_IT_SOURCE(&huart1, UART_IT_TXE)!= RESET) 
	{
    
    
		prvvUARTTxReadyISR();//发送中断
	}
	
  HAL_NVIC_ClearPendingIRQ(USART1_IRQn);
  HAL_UART_IRQHandler(&huart1);
  /* USER CODE BEGIN USART1_IRQn 1 */

  /* USER CODE END USART1_IRQn 1 */
}

修改 HardFault_Handler 函数，这个函数用于设置设备中断，这里如果不修改则会直接报错重复定义，所以,这里我们直接修改为 I2C 的中断函数即可

修改后代码如下：

/**
  * @brief This function handles I2C1 event interrupt.
  */
void I2C1_EV_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN I2C1_EV_IRQn 0 */

  /* USER CODE END I2C1_EV_IRQn 0 */
  HAL_I2C_EV_IRQHandler(&hi2c1);
  /* USER CODE BEGIN I2C1_EV_IRQn 1 */

  /* USER CODE END I2C1_EV_IRQn 1 */
}

增加 HAL_TIM_PeriodElapsedCallback 函数，用于定时器中断回调函数

函数代码如下：

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)	//定时器中断回调函数，用于连接porttimer.c文件的函数
{
    
    
  /* NOTE : This function Should not be modified, when the callback is needed,
            the __HAL_TIM_PeriodElapsedCallback could be implemented in the user file
   */
	prvvTIMERExpiredISR( );
}

新增 DMA 与 I2C 中断设置函数

函数代码如下：

/**
  * @brief This function handles DMA1 channel6 global interrupt.
  */
void DMA1_Channel6_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN DMA1_Channel6_IRQn 0 */

  /* USER CODE END DMA1_Channel6_IRQn 0 */
  HAL_DMA_IRQHandler(&hdma_i2c1_tx);
  /* USER CODE BEGIN DMA1_Channel6_IRQn 1 */

  /* USER CODE END DMA1_Channel6_IRQn 1 */
}

/**
  * @brief This function handles DMA1 channel7 global interrupt.
  */
void DMA1_Channel7_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN DMA1_Channel7_IRQn 0 */

  /* USER CODE END DMA1_Channel7_IRQn 0 */
  HAL_DMA_IRQHandler(&hdma_i2c1_rx);
  /* USER CODE BEGIN DMA1_Channel7_IRQn 1 */

  /* USER CODE END DMA1_Channel7_IRQn 1 */
}

6. stm32f1xx_it.c 完整代码如下：

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    stm32f1xx_it.c
  * @brief   Interrupt Service Routines.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2022 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */

/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "stm32f1xx_it.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN TD */
/* USER CODE END TD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
/* USER CODE BEGIN PFP */
extern void prvvUARTTxReadyISR(void);
extern void prvvUARTRxISR(void);
extern void prvvTIMERExpiredISR( void );
/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/* External variables --------------------------------------------------------*/
extern DMA_HandleTypeDef hdma_i2c1_rx;
extern DMA_HandleTypeDef hdma_i2c1_tx;
extern I2C_HandleTypeDef hi2c1;
extern TIM_HandleTypeDef htim3;
extern UART_HandleTypeDef huart1;
/* USER CODE BEGIN EV */

/* USER CODE END EV */

/******************************************************************************/
/*           Cortex-M3 Processor Interruption and Exception Handlers          */
/******************************************************************************/
/**
  * @brief This function handles Non maskable interrupt.
  */
void NMI_Handler(void)
{
    
    
  /* USER CODE BEGIN NonMaskableInt_IRQn 0 */

  /* USER CODE END NonMaskableInt_IRQn 0 */
  /* USER CODE BEGIN NonMaskableInt_IRQn 1 */
  while (1)
  {
    
    
  }
  /* USER CODE END NonMaskableInt_IRQn 1 */
}

/**
  * @brief This function handles I2C1 event interrupt.
  */
void I2C1_EV_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN I2C1_EV_IRQn 0 */

  /* USER CODE END I2C1_EV_IRQn 0 */
  HAL_I2C_EV_IRQHandler(&hi2c1);
  /* USER CODE BEGIN I2C1_EV_IRQn 1 */

  /* USER CODE END I2C1_EV_IRQn 1 */
}

/**
  * @brief This function handles Memory management fault.
  */
void MemManage_Handler(void)
{
    
    
  /* USER CODE BEGIN MemoryManagement_IRQn 0 */

  /* USER CODE END MemoryManagement_IRQn 0 */
  while (1)
  {
    
    
    /* USER CODE BEGIN W1_MemoryManagement_IRQn 0 */
    /* USER CODE END W1_MemoryManagement_IRQn 0 */
  }
}

/**
  * @brief This function handles Prefetch fault, memory access fault.
  */
void BusFault_Handler(void)
{
    
    
  /* USER CODE BEGIN BusFault_IRQn 0 */

  /* USER CODE END BusFault_IRQn 0 */
  while (1)
  {
    
    
    /* USER CODE BEGIN W1_BusFault_IRQn 0 */
    /* USER CODE END W1_BusFault_IRQn 0 */
  }
}

/**
  * @brief This function handles Undefined instruction or illegal state.
  */
void UsageFault_Handler(void)
{
    
    
  /* USER CODE BEGIN UsageFault_IRQn 0 */

  /* USER CODE END UsageFault_IRQn 0 */
  while (1)
  {
    
    
    /* USER CODE BEGIN W1_UsageFault_IRQn 0 */
    /* USER CODE END W1_UsageFault_IRQn 0 */
  }
}

/**
  * @brief This function handles Debug monitor.
  */
void DebugMon_Handler(void)
{
    
    
  /* USER CODE BEGIN DebugMonitor_IRQn 0 */

  /* USER CODE END DebugMonitor_IRQn 0 */
  /* USER CODE BEGIN DebugMonitor_IRQn 1 */

  /* USER CODE END DebugMonitor_IRQn 1 */
}

/******************************************************************************/
/* STM32F1xx Peripheral Interrupt Handlers                                    */
/* Add here the Interrupt Handlers for the used peripherals.                  */
/* For the available peripheral interrupt handler names,                      */
/* please refer to the startup file (startup_stm32f1xx.s).                    */
/******************************************************************************/

/**
  * @brief This function handles DMA1 channel6 global interrupt.
  */
void DMA1_Channel6_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN DMA1_Channel6_IRQn 0 */

  /* USER CODE END DMA1_Channel6_IRQn 0 */
  HAL_DMA_IRQHandler(&hdma_i2c1_tx);
  /* USER CODE BEGIN DMA1_Channel6_IRQn 1 */

  /* USER CODE END DMA1_Channel6_IRQn 1 */
}

/**
  * @brief This function handles DMA1 channel7 global interrupt.
  */
void DMA1_Channel7_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN DMA1_Channel7_IRQn 0 */

  /* USER CODE END DMA1_Channel7_IRQn 0 */
  HAL_DMA_IRQHandler(&hdma_i2c1_rx);
  /* USER CODE BEGIN DMA1_Channel7_IRQn 1 */

  /* USER CODE END DMA1_Channel7_IRQn 1 */
}


/**
  * @brief This function handles TIM3 global interrupt.
  */
void TIM3_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN TIM3_IRQn 0 */

  /* USER CODE END TIM3_IRQn 0 */
  HAL_TIM_IRQHandler(&htim3);
  /* USER CODE BEGIN TIM3_IRQn 1 */

  /* USER CODE END TIM3_IRQn 1 */
}

/**
  * @brief This function handles USART1 global interrupt.
  */
void USART1_IRQHandler(void)
{
    
    
  /* USER CODE BEGIN USART1_IRQn 0 */

  /* USER CODE END USART1_IRQn 0 */
  HAL_UART_IRQHandler(&huart1);
  /* USER CODE BEGIN USART1_IRQn 1 */
	if(__HAL_UART_GET_IT_SOURCE(&huart1, UART_IT_RXNE)!= RESET) 
	{
    
    
		prvvUARTRxISR();//接收中断
	}

	if(__HAL_UART_GET_IT_SOURCE(&huart1, UART_IT_TXE)!= RESET) 
	{
    
    
		prvvUARTTxReadyISR();//发送中断
	}
	
  HAL_NVIC_ClearPendingIRQ(USART1_IRQn);
  HAL_UART_IRQHandler(&huart1);
  /* USER CODE BEGIN USART1_IRQn 1 */

  /* USER CODE END USART1_IRQn 1 */
}

/* USER CODE BEGIN 1 */

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)	//定时器中断回调函数，用于连接porttimer.c文件的函数
{
    
    
  /* NOTE : This function Should not be modified, when the callback is needed,
            the __HAL_TIM_PeriodElapsedCallback could be implemented in the user file
   */
	prvvTIMERExpiredISR( );
}


/* USER CODE END 1 */

7. 修改 demo.c 文件

/*
 * FreeModbus Libary: BARE Demo Application
 * Copyright (C) 2006 Christian Walter <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * File: $Id$
 */

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"
#include "AHT.h"
/* ----------------------- Defines ------------------------------------------*/
#define REG_INPUT_START 0	
#define REG_INPUT_NREGS 5

/* ----------------------- Static variables ---------------------------------*/
static USHORT   usRegInputStart = REG_INPUT_START;
//static USHORT   usRegInputBuf[REG_INPUT_NREGS];

uint16_t   usRegInputBuf[REG_INPUT_NREGS];
uint16_t InputBuff[5];


/* ----------------------- Start implementation -----------------------------*/
/*int main( void )
{
    eMBErrorCode    eStatus;

    eStatus = eMBInit( MB_RTU, 0x0A, 0, 38400, MB_PAR_EVEN );

    eStatus = eMBEnable(  );

    for( ;; )
    {
        ( void )eMBPoll(  );

        usRegInputBuf[0]++;
    }
}*/
uint32_t CT_data[2]={
    
    0,0};
	volatile int  c1,c2,t1,t2;
eMBErrorCode eMBRegInputCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs )
{
    
    
	eMBErrorCode eStatus = MB_ENOERR;
	int iRegIndex;
	int i;
		AHT20_Read_CTdata_crc(CT_data);  //crc校验后，读取AHT20的温度和湿度数据 
		c1 = CT_data[0]*1000/1024/1024;  //计算得到湿度值c1（放大了10倍）
		t1 = CT_data[1]*2000/1024/1024-500;//计算得到温度值t1（放大了10倍）
		c2 = c1/10 + (c1/10)%10;
		t2 = t1/10 + (t1/10)%10;
		InputBuff[0] = t2; //温度整数位
		InputBuff[1] = t1%10; //温度小数点后一位
		InputBuff[2] = c2;	//湿度整数位
		InputBuff[3] = c2%10;//湿度小数点后一位
	
	if( ( usAddress >= REG_INPUT_START ) && ( usAddress + usNRegs <= REG_INPUT_START + REG_INPUT_NREGS ) )
	{
    
    
		iRegIndex = ( int )( usAddress - usRegInputStart );
		for(i=0;i<usNRegs;i++)
		{
    
    
			*pucRegBuffer=InputBuff[i+usAddress-1]>>8;
			pucRegBuffer++;
			*pucRegBuffer=InputBuff[i+usAddress-1]&0xff;
			pucRegBuffer++;
		}
	}
	else
	{
    
    
		eStatus = MB_ENOREG;
	}

	return eStatus;
}

eMBErrorCode eMBRegHoldingCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs,
                 eMBRegisterMode eMode )
{
    
    
    return MB_ENOREG;
}


eMBErrorCode eMBRegCoilsCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNCoils,
               eMBRegisterMode eMode )
{
    
    
    return MB_ENOREG;
}

eMBErrorCode eMBRegDiscreteCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNDiscrete )
{
    
    
    return MB_ENOREG;
}

（2）修改RT_Thread代码

1. 找到Middlewares/RT-Thread/RTOS/kernel文件夹下的board.c文件，修改串口USART2为USART1
   
2. 找到Application/User/Core里app_rt_thread.c下的rtconfig.h
   

（3）修改main代码

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2022 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under Ultimate Liberty license
  * SLA0044, the "License"; You may not use this file except in compliance with
  * the License. You may obtain a copy of the License at:
  *                             www.st.com/SLA0044
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "rtthread.h"	// RT-Thread 头文件
#include "dma.h"
#include "i2c.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"
#include "mb.h"
#include "mbport.h"
#include "AHT.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
extern void MX_RT_Thread_Init(void);	// RT-Thread 初始化函数，初始化并执行各种进程
extern void MX_RT_Thread_Process(void);	// RT-Thread 主进程
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
    
    
  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_I2C1_Init();
  MX_TIM3_Init();
  MX_USART1_UART_Init();
  /* USER CODE BEGIN 2 */
	AHT20_Init();	//初始化温度传感器并进行延时确保数据准确性
//	HAL_Delay(2000);
	eMBInit( MB_RTU, 0x01, 1, 115200, MB_PAR_NONE);//初始化modbus，走modbusRTU，从站地址为0x01，端口为1。
	eMBEnable();//使能modbus
	MX_RT_Thread_Init();	//初始化 RT-Thread 进程
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    
    
		
		//( void )eMBPoll(  );//启动modbus侦听，由于在 RT-Thread 主进程中进行了监听启动，所以这里直接调用 RT-Thread 主进程
		
		MX_RT_Thread_Process();	//调用主进程
		
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
    
    
  RCC_OscInitTypeDef RCC_OscInitStruct = {
    
    0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {
    
    0};

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    
    
    Error_Handler();
  }
  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    
    
    Error_Handler();
  }
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
    
    
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
    
    
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
    
    
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

五、电路连接

DHT20的芯片引脚定义：

根据设计的程序连接电路：
对于USB转TTL模块和stm32f103c8t6连接：
GND — GND
3v3 — 3v3
TXD — A10
RXD — A9

总电路：
PB6 连接 SCL（串行时钟）
PB7 连接 SDA （串行数据）

六、运行结果

七、实验总结

RT_Thread移植较为繁琐，RT-Thread Nano ，它是一个极简版的硬实时内核，它是由 C 语言开发，采用面向对象的编程思维，具有良好的代码风格，是一款可裁剪的、抢占式实时多任务的 RTOS。其内存资源占用极小。Nano开源免费，小巧，简单是它的优点。本次实验更加熟悉了Modbus协议的工作原理