[STM32F411Nucleo Review] Porting Freemodbus Library

pomin

[STM32F411Nucleo Review] Porting Freemodbus Library [Copy link]

> This article introduces how to transplant the FreeModbus library and implement Modbus communication on the Nucleo-F411 board.## Data preparation The FreeModbus code is stored in GitHub, the address is https://github.com/cwalter-at/freemodbus, pull it to the local, the key is the demo and modbus folders, demo stores some transplanted projects, modbus stores the library code. <ignore_js_op> <img style="cursor:pointer;" id="aimg_792117" aid="792117" src="/bbs/static/image/common/none.gif" onclick="zoom(this, this.getAttribute('zoomfile'), 0, 0, '0')" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220248cgs28loo1be52sgz.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220248cgs28loo1be52sgz.png" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792117_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240301000426.png</strong> <em class="xg1">(80.83 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792117" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792117&handlekey=savephoto_792117">save to album</a> </p> <p class="xg1 y">2024-3-4 22:02 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op> ## Hardware connection The serial port in the schematic diagram is connected to the virtual serial port of STLink, and the pins are PA2 and PA3 <ignore_js_op> <img style="cursor:pointer;" id="aimg_792118" aid="792118" src="/bbs/static/image/common/none.gif" onclick="zoom(this, this.getAttribute('zoomfile'), 0, 0, '0')" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220255v03arsffs0lf5s5l.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220255v03arsffs0lf5s5l.png" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792118_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240228000007.png</strong> <em class="xg1">(257.94 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792118" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792118&handlekey=savephoto_792118">save to album</a> </p> <p class="xg1 y">2024-3-4 22:02 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op> ## Interface configuration Add the pulled FreeModbus code to the keil project, where you need to add the functions in the library code, the code in the rtu folder and mb.c <ignore_js_op> <img style="cursor:pointer;" id="aimg_792119" aid="792119" src="/bbs/static/image/common/none.gif" onclick="zoom(this, this.getAttribute('zoomfile'), 0, 0, '0')" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220302smxpfw3w3x71jwjt.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220302smxpfw3w3x71jwjt.png" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792119_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240301000725.png</strong> <em class="xg1">(67.57 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792119" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792119&handlekey=savephoto_792119">save to album</a> </p> <p class="xg1 y">2024-3-4 22:03 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op> In addition, you also need to copy the code in the BARE folder in the demo to the project. Here, modify demo.c to data.c and add it to the project <ignore_js_op> <img id="aimg_792120" style="cursor:pointer;" aid="792120" src="/bbs/static/image/common/none.gif" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220308w3abczctdcthm3bn.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220308w3abczctdcthm3bn.png" class="zoom" onclick="zoom(this, this.src, 0, 0, 0)" width="667" id="aimg_792120" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792120_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240301000826.png</strong> <em class="xg1">(24.74 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792120" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792120&handlekey=savephoto_792120">save to album</a> </p> <p class="xg1 y">2024-3-4 22:03 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op> The added code files are as follows <ignore_js_op> <img id="aimg_792121" style="cursor:pointer;" aid="792121" src="/bbs/static/image/common/none.gif" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220316bvrrlqcrtjougwbd.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220316bvrrlqcrtjougwbd.png" class="zoom" onclick="zoom(this, this.src, 0, 0, 0)" width="363" id="aimg_792121" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792121_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240229235922.png</strong> <em class="xg1">(41.91 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792121" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792121&handlekey=savephoto_792121">save to album</a> </p> <p class="xg1 y">2024-3-4 22:03 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op> The required code files have been added. Now start to adapt portxxx.c, where portserial.c is the interface layer of the serial port, and porttimer.c is the interface layer of the timer. Configure USART2 with the following parameters, set the baud rate to 115200bps <ignore_js_op> <img style="cursor:pointer;" id="aimg_792122" aid="792122" src="/bbs/static/image/common/none.gif" onclick="zoom(this, this.getAttribute('zoomfile'), 0, 0, '0')" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220324mgqj1eb93x0y3xl3.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220324mgqj1eb93x0y3xl3.png" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792122_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240301001327.png</strong> <em class="xg1">(72.26 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792122" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792122&handlekey=savephoto_792122">save to album</a> </p> <p class="xg1 y">2024-3-4 22:03 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op> Set the TIM11 timer period to 50us <ignore_js_op> <img id="aimg_792123" style="cursor:pointer;" aid="792123" src="/bbs/static/image/common/none.gif" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220330ptla8z0ltx6tx263.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220330ptla8z0ltx6tx263.png" class="zoom" onclick="zoom(this, this.src, 0, 0, 0)" width="692" id="aimg_792123" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792123_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240301001316.png</strong> <em class="xg1">(60.66 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792123" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792123&handlekey=savephoto_792123">save to album</a> </p> <p class="xg1 y">2024-3-4 22:03 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op> At the same time, enable the interrupts of USART2 and TIM11 <ignore_js_op> <img id="aimg_792124" style="cursor:pointer;" aid="792124" src="/bbs/static/image/common/none.gif" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220336x6zwwk9elll9f161.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220336x6zwwk9elll9f161.png" class="zoom" onclick="zoom(this, this.src, 0, 0, 0)" width="684" id="aimg_792124" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792124_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240301001231.png</strong> <em class="xg1">(148.5 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792124" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792124&handlekey=savephoto_792124">save to album</a> </p> <p class="xg1 y">2024-3-4 22:03 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op> ### Serial port interface adaptation Use the two callback functions of the two HAL libraries HAL_UART_TxCpltCallback and HAL_UART_RxCpltCallback to write the following code```c void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) { if(huart->Instance == uart->Instance) { pxMBFrameCBByteReceived(); HAL_UART_Receive_IT(uart, &singlechar, 1); } } void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart) { if(huart->Instance == uart->Instance) { pxMBFrameCBTransmitterEmpty(); } } ```` The serial port transceiver interface code is as follows```c /* ---------------------------- Static variables ---------------------------------*/ UART_HandleTypeDef *uart = &huart2; static uint8_t singlechar; /* ---------------------------- Start implementation --------------------------*/ BOOL xMBPortSerialInit( UCHAR ucPort, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity ) { return TRUE; } void vMBPortSerialEnable(BOOL xRxEnable, BOOL xTxEnable) { if(xRxEnable) { HAL_UART_Receive_IT(uart, &singlechar, 1); } else { HAL_UART_AbortReceive_IT(uart); } if(xTxEnable) { pxMBFrameCBTransmitterEmpty(); } else { HAL_UART_AbortTransmit_IT(uart); } } void vMBPortClose(void) { HAL_UART_AbortReceive_IT(uart); HAL_UART_AbortTransmit_IT(uart); } BOOL xMBPortS erialPutByte(CHAR ucByte) { HAL_UART_Transmit_IT(uart, (uint8_t*)&ucByte, 1); return TRUE; } BOOL xMBPortSerialPutBytes(volatile UCHAR *ucByte, USHORT usSize) { HAL_UART_Transmit_IT(uart, (uint8_t *)ucByte,usSize); return TRUE; } BOOL xMBPortSerialGetByte(CHAR * pucByte) { *pucByte = (uint8_t)(singlechar); return TRUE; } ``` ### The timer interface adapter timer uses HAL_TIM_PeriodElapsedCallback. The callback function for the timer period interrupt provided by this HAL```c void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) { if(htim->Instance == tim->Instance) { if((++counter) >= timeout) pxMBPortCBTimerExpired(); } } ``` The other codes are some interface codes for enabling and disabling TIM```c /* ----------------------- User defenitions ---------------------------------*/ TIM_HandleTypeDef *tim = &htim11; static uint16_t timeout = 0; volatile uint16_t counter = 0; /* ----------------------- Start implementation -----------------------------*/ BOOL xMBPortTimersInit( USHORT usTim1Timerout50us ) { timeout = usTim1Timerout50us; return TRUE; } inline void vMBPortTimersEnable() { counter=0; HAL_TIM_Base_Start_IT(tim); } inline void vMBPortTimersDisable() { HAL_TIM_Base_Stop_IT(tim); } inline void vMBPortTimersDelay( USHORT usTimeOutMS ) { HAL_Delay(usTimeOutMS); } ``` At this point, the code of the interface layer has been adapted. The amount of code is not large and it is relatively easy. Now let's start the main function to write application code to verify. ## Verification Change the code before and after the while in the main function to the following code. First initialize the modbus library and then enable it, and poll in the while loop. ```c eMBInit(MB_RTU, 0x01, 0, 115200, MB_PAR_NONE); // Initialize modbus to RTU mode, baud rate 9600, odd parity eMBEnable(); // Enable modbus protocol stack /* USER CODE END 2 */ /* Infinite loop */ /* USER CODE BEGIN WHILE */ while (1) { /* USER CODE END WHILE */ /* USER CODE BEGIN 3 */ eMBPoll(); // Polling query } /* USER CODE END 3 */ ``` These are not enough. Now that the adaptation of the communication process has been completed, it is also necessary to provide data source code such as holding registers and coils. Write the following code in data.c```c #include "mb.h" #include "mbport.h" // Ten input registers #define REG_INPUT_SIZE 10 uint16_t REG_INPUT_BUF[REG_INPUT_SIZE]; // Ten holding registers #define REG_HOLD_SIZE 10 uint16_t REG_HOLD_BUF[REG_HOLD_SIZE]; // Ten coils #define REG_COILS_SIZE 10 uint8_t REG_COILS_BUF[REG_COILS_SIZE] = {1, 1, 1, 1, 0, 0, 0, 0, 1, 1}; // Ten discrete quantities #define REG_DISC_SIZE 10 uint8_t REG_DISC_BUF[REG_DISC_SIZE] = {1,1,1,1,0,0,0,0,1,1}; /// CMD4 command processing callback function eMBErrorCode eMBRegInputCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs ) { USHORT usRegIndex = usAddress - 1; // Illegal detection if((usRegIndex + usNRegs) > REG_INPUT_SIZE) { return MB_ENOREG; } // Loop reading while( usNRegs > 0 ) { *pucRegBuffer++ = ( unsigned char )( REG_INPUT_BUF[usRegIndex] >> 8 ); *pucRegBuffer++ = ( unsigned char )( REG_INPUT_BUF[usRegIndex] & 0xFF ); usRegIndex++; usNRegs--; } // Analog input register is changed for(usRegIndex = 0; usRegIndex < REG_INPUT_SIZE; usRegIndex++) { REG_INPUT_BUF[usRegIndex]++; } return MB_ENOERR; } /// CMD6, 3, 16 command processing callback function eMBErrorCode eMBRegHoldingCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs,eMBRegisterMode eMode ) { USHORT usRegIndex = usAddress - 1; // Illegal detection if((usRegIndex + usNRegs) > REG_HOLD_SIZE) { return MB_ENOREG; } // Write register if(eMode == MB_REG_WRITE) { while( usNRegs > 0 ) { REG_HOLD_BUF[usRegIndex] = (pucRegBuffer[0] << 8) | pucRegBuffer[1]; pucRegBuffer += 2; usRegIndex++; usNRegs--; } } // Read register else { while( usNRegs > 0 ) { *pucRegBuffer++ = ( unsigned char )( REG_HOLD_BUF[usRegIndex] >> 8 ); *pucRegBuffer++ = ( unsigned char )( REG_HOLD_BUF[usRegIndex] & 0xFF ); usRegIndex++; usNRegs--; } } return MB_ENOERR; } /// CMD1, 5, 15 command processing callback function eMBErrorCode eMBRegCoilsCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNCoils, eMBRegisterMode eMode ) { USHORT usRegIndex = usAddress - 1; UCHAR ucBits = 0; UCHAR ucState = 0; UCHAR ucLoops = 0; // Illegal detection if((usRegIndex + usNCoils) > REG_COILS_SIZE) { return MB_ENOREG; } if(eMode == MB_REG_WRITE) { ucLoops = (usNCoils - 1) / 8 + 1; while(ucLoops != 0) { ucState = *pucRegBuffer++; ucBits = 0; while(usNCoils != 0 && ucBits < 8) { REG_COILS_BUF[usRegIndex++] = (ucState >> ucBits) & 0X01; usNCoils--; ucBits++; } ucLoops--; } } else { ucLoops = (usNCoils - 1) / 8 + 1; while(ucLoops != 0) { State = 0; ucBits = 0; while(usNCoils != 0 && ucBits < 8) { if(REG_COILS_BUF[usRegIndex]) { ucState |= (1 << ucBits); } usNCoils--; usRegIndex++; ucBits++; } *pucRegBuffer++ = ucState; ucLoops--; } } return MB_EN OERR; } /// CMD2 command processing callback function eMBErrorCode eMBRegDiscreteCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNDiscrete ) { USHORT usRegIndex = usAddress - 1; UCHAR ucBits = 0; UCHAR ucState = 0; UCHAR ucLoops = 0; // Illegal detection if((usRegIndex + usNDiscrete) > REG_DISC_SIZE) { return MB_ENOREG; } ucLoops = (usNDiscrete - 1) / 8 + 1; while(ucLoops != 0) { ucState = 0; ucBits = 0; while(usNDiscrete != 0 && ucBits < 8) { if(REG_DISC_BUF[usRegIndex]) { ucState |= (1 << ucBits); } usNDiscrete--; usRegIndex++; ucBits++; } *pucRegBuffer++ = ucState; ucLoops--; } // Simulate discrete input being changed for(usRegIndex = 0; usRegIndex < REG_DISC_SIZE; usRegIndex++) { REG_DISC_BUF[usRegIndex] = !REG_DISC_BUF[usRegIndex]; } return MB_ENOERR; } ``` Ten input registers, discrete quantities, holding registers, and coils are set, and the discrete quantity and input register simulations are constantly changing. The program is compiled and burned to the development board. MThing is used to view the coil status and the value of an input register, which is the same as expected. <ignore_js_op> <img style="cursor:pointer;" id="aimg_792125" aid="792125" src="/bbs/static/image/common/none.gif" onclick="zoom(this, this.getAttribute('zoomfile'), 0, 0, '0')" zoomfile="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220353kiizuiunu2uyx33z.png" file="//bbs.eeworld.com.cn/data/attachment/forum/202403/04/220353kiizuiunu2uyx33z.png" inpost="1" onmouseover="showMenu({'ctrlid':this.id,'pos':'12'})" /> <div class="tip tip_4 aimg_tip" id="aimg_792125_menu" style="position: absolute; display: none" disautofocus="true"> <div class="xs0"> <p><strong>Pasted image 20240301002640.png</strong> <em class="xg1">(180.66 KB, downloads: 0)</em></p> <p> <a href="javascript:;" class="loginf" >download attach</a> <a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_792125" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=792125&handlekey=savephoto_792125">save to album</a> </p> <p class="xg1 y">2024-3-4 22:03 上传</p> </div> <div class="tip_horn"></div> </div> </ignore_js_op>

qiao---

Excuse me, what modbus debugging tool are you using?

pomin

qiao--- Posted on 2024-3-10 00:07 May I ask what modbus debugging tool you are using?

mthings

freebsder

Thank you for sharing, and I look forward to subsequent attempts related to modbus.

chejm

Thank you for sharing the technical content. It broadened my horizons and is worth learning. I hope you can provide better content in the future.