Article directory

foreword
1 Porting RT-Thread
- 1.1 CubeMX install Nano pack
- 1.2 CubeMX create project
2 Keil modify the code
3 Effect display
Summarize

foreword

Software version
STM32CubeMX 6.4 0
Keil 531
Hardware
STM32F103C8T6
AHT20 temperature and humidity sensor

Topic requirements

Use the stm32 minimum core board + AHT20 module to complete a temperature and humidity Slave device with a modbus interface, which allows the upper computer PC to obtain temperature and humidity through the modbus protocol. The main program adopts a multi-tasking framework, such as RT-thread Nano.

1 Porting RT-Thread

1.1 CubeMX install Nano pack

Official download reference
https://www.rt-thread.org/document/site/#/rt-thread-version/rt-thread-nano/nano-port-cube/an0041-nano-port-cube

Get the package address To get the RT-Thread Nano software package, you need to add https://www.rt-thread.org/download/cube/RealThread.RT-Thread.pdsc
in CubeMX
Open CubeMX, helpenter Manage embedded software packages, click From Urlthe button to enter User Defined Packs Manager the interface, then click new, fill in the above URL, and click check.
After the download and installation is complete, the check box in front turns green

1.2 CubeMX create project

Select the Nano component
and click Softwares Packages-> Select Componentsto enter the component configuration interface

. Select RealThread, then root the 3.1.5 version, and then click. OK

At this time, a new addition will be Software Packsadded, and you can see the added RealThread.RT_Threadcontent. Check the corresponding content
RCC configuration
SYS configuration
USART1
NVIC selects

the RT-Thread operating system to redefine HardFault_Handler, , PendSV_Handlerand SysTick_Handlerinterrupt functions. In order to avoid the problem of repeated definitions, before generating the project, it is necessary to deselect the three interrupt functions in the interrupt configuration and code generation options.
GPIO
selects B15 as indicator light
clock configuration

2 Keil modify the code

For the detailed code of AHT20 collection, see the previous blog
https://blog.csdn.net/apple_52030329/article/details/127854432

2.1 Adding files

Under the folder of the Cube generated project, MDK-ARMcreate an AHT folder under the folder, and under this folder, add the following files

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Add files to the project

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2.2 Transplant freeModusRTU

Download link: https://github.com/cwalter-at/freemodbus

Unzip and open the file you just downloaded, click into the demo, and create a new STM32MB folder

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Copy all the files in the BARE folder to the newly created STM32MB folder,
and then copy all the modbus folders to the newly created STM32MB folder. The final result is as follows:

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Open the MDK-ARM folder and copy the STM32MB file here

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Create a new group named MB and MB_Port, add all .c files in the modbus folder under the STM32MB folder to MB, add all .c files in the port folder under the STM32MB folder to MB_Port and the demo.c file in the root directory:

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Add header file path

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2.3 Modify the code

portserial.c

#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 )	//添加发送一位代码
			   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(  );
}

porttimer.c

/*
 * 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"
#include "stm32f1xx_hal.h"
#include "tim.h"
/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"

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

/* ----------------------- Start implementation -----------------------------*/
BOOL
xMBPortTimersInit( USHORT usTim1Timerout50us )//定时器初始化直接返回TRUE，已经在mian函数初始化过
{
    
    
    return  TRUE;
}


inline void
vMBPortTimersEnable(  )//使能定时器中断，我用的是定时器4，所以为&htim4
{
    
    
    /* Enable the timer with the timeout passed to xMBPortTimersInit( ) */
				 /* 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 )//modbus定时器动作，需要在中断内使用
{
    
    
    ( void )pxMBPortCBTimerExpired(  );
}

stm32f1xx_it.c

/* 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 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 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 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 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 */

demo.c

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"
#include "AHT20-21_DEMO_V1_3.h" 

/* ----------------------- Defines ------------------------------------------*/
#define REG_INPUT_START 0
#define REG_INPUT_NREGS 5

/* ----------------------- Static variables ---------------------------------*/
static USHORT   usRegInputStart = REG_INPUT_START;
//static 
uint16_t   usRegInputBuf[REG_INPUT_NREGS];
uint16_t InputBuff[5];
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;
		InputBuff[1] = c2;
		InputBuff[2] = 0x01;
		InputBuff[3] = 0x01;
		
    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;
}

Create a task and create a new file Application/USERunder the folderapp_rt_thread.c

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Add the following code

#include "rtthread.h"
#include "main.h"
#include "stdio.h"
#include "usart.h"
#include "AHT20-21_DEMO_V1_3.h" 
#include "mb.h"
#include "mbport.h"
 
struct rt_thread led1_thread;
rt_uint8_t rt_led1_thread_stack[128];
void led1_task_entry(void *parameter);
 
 
//初始化线程函数
void MX_RT_Thread_Init(void)
{
    
    
	//初始化LED1线程
	rt_thread_init(&led1_thread,"led1",led1_task_entry,RT_NULL,&rt_led1_thread_stack[0],sizeof(rt_led1_thread_stack),3,20);
	//开启线程调度
	rt_thread_startup(&led1_thread);
}
 
//主任务
void MX_RT_Thread_Process(void)
{
    
    
	( void )eMBPoll(  );//启动modbus侦听

}
 
//LED1任务
void led1_task_entry(void *parameter)
{
    
    
	while(1)
	{
    
    
		HAL_GPIO_WritePin(GPIOB,GPIO_PIN_15, GPIO_PIN_RESET);
		rt_thread_delay(500);
		HAL_GPIO_WritePin(GPIOB,GPIO_PIN_15, GPIO_PIN_SET);
		rt_thread_delay(500);
	}
}

Find the files Middlewares/RT-Thread/RTOS/kernelin the folder board.c, modify the serial port USART2 to USART1

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Find rtconfig.h under app_rt_thread.c in Application/User/Core

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mian.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @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 "dma.h"
#include "i2c.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"
#include "mb.h"
#include "mbport.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <stdio.h>
#include "AHT20-21_DEMO_V1_3.h" 
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
extern void MX_RT_Thread_Init(void);
extern void MX_RT_Thread_Process(void);
/* 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_USART1_UART_Init();
  MX_TIM3_Init();
	AHT20_Init();
	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
  /* USER CODE BEGIN 2 */
 MX_RT_Thread_Init();
 
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    
    
    /* USER CODE END WHILE */
		( void )eMBPoll(  );//启动modbus侦听
    /* 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 */

3 Effect display

After modifying the above code, compile and burn.

Due to the epidemic situation, I returned to school and went home. I don’t have the AHT20 sensor on hand at present, and the effect will be added after returning to school. If the sensor is connected, the effect should be that the temperature and humidity values can be seen by using Modbusposs to receive data, and at the same time, the small light bulb as the indicator light will flash.

Summarize

This experiment further studied the application of Modbus protocol, and also completed the transplantation of RT-Thread.

Reference:
https://blog.csdn.net/weixin_46129506/article/details/121914039
https://blog.csdn.net/qq_47281915/article/details/122328414
https://blog.csdn.net/weixin_56102526/article/ details/121952050

STM32 uses Modbus protocol to read temperature and humidity

Article directory

foreword

1 Porting RT-Thread

1.1 CubeMX install Nano pack

1.2 CubeMX create project

2 Keil modify the code

2.1 Adding files

2.2 Transplant freeModusRTU

2.3 Modify the code

3 Effect display

Summarize

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