title: STM32G0开发笔记-Platformio+libopencm3-FreeRTOS和FreeModbus库使用
tags:

• STM32
• MCU
• STM32G070
• libopencm3
• MonkeyPi
• FreeRTOS
• Modbus
  categories:
  • STM32
    date: 2022-9-11 19:52:05

[原文：makerinchina.cn]

使用Platformio平台的libopencm3开发框架来开发STM32G0，以下为FreeRTOS和FreeModbus库使用。

1 新建项目

• 建立freertos_modbus项目

在PIO的Home页面新建项目，项目名称freertos_modbus，选择开发板为 MonkeyPi_STM32_G070RB，开发框架选择libopencm3；

• 项目建立完成后在src目录下新建main.c主程序文件；
• 修改下载和调试方式，这里开发板使用的是DAPLink仿真器，因此修改platformio.ini文件如下：

upload_protocol = cmsis-dap
debug_tool = cmsis-dap

2 编写程序

直接在之前的FreeRTOS工程上进行添加；

2.1 添加 freeModbus 库

从git仓库下载源码： https://github.com/cwalter-at/freemodbus

将下载的源码中的mobus文件夹放置到工程的lib目录下，然后在modbus目录新建library.json文件，内容如下：

{"name": "FreeModbus","version": "master","repository":{"type":"git","url":"https://github.com/cwalter-at/freemodbus"},"build": {"flags": ["-Iascii","-Ifunctions","-Iinclude","-Irtu","-Itcp"],"srcFilter": ["+<*>"]}
}

然后从FreeModbus源码中的 demo\BARE\port中复制文件到工程的src\modbus_port文件夹下，最后的文件夹结构如下：

2.2 移植

• portevent:

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"
#include "FreeRTOS.h"
#include "task.h"/* ----------------------- Variables ----------------------------------------*/
static eMBEventType eQueuedEvent;
static BOOL     xEventInQueue;
static uint32_t modbus_last_active_time = 0;uint32_t get_modbus_last_active_time(void)
{return modbus_last_active_time;
}/* ----------------------- Start implementation -----------------------------*/
BOOL
xMBPortEventInit( void )
{xEventInQueue = FALSE;return TRUE;
}BOOL
xMBPortEventPost( eMBEventType eEvent )
{xEventInQueue = TRUE;eQueuedEvent = eEvent;if (eEvent == EV_EXECUTE) {modbus_last_active_time = xTaskGetTickCount();}return TRUE;
}BOOL
xMBPortEventGet( eMBEventType * eEvent )
{BOOL            xEventHappened = FALSE;if( xEventInQueue ){*eEvent = eQueuedEvent;xEventInQueue = FALSE;xEventHappened = TRUE;}return xEventHappened;
}

• portserial

这里使用RS485，因此需要对RS485使能端口进行配置，其他为串口的配置，然后在发送和接收中断时候调用modbus相关接口进行处理：

#include "port.h"#include "FreeRTOS.h"
#include "queue.h"#include 
#include 
#include 
#include /* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"/* ----------------------- static functions ---------------------------------*/xQueueHandle uart_queue;#define RS485_1_CLOCK		RCC_GPIOB
#define RS485_1_EN_PORT		GPIOB
#define RS485_1_EN_PIN		GPIO8static void rs485_delay(int n)
{while (--n) {__asm__ volatile ("nop");}
}static inline void rs485_1_rx_mode(void)
{gpio_clear(RS485_1_EN_PORT, RS485_1_EN_PIN);
}static inline void rs485_1_tx_mode(void)
{gpio_set(RS485_1_EN_PORT, RS485_1_EN_PIN);
}static inline void rs485_gpio_init(void)
{rcc_periph_clock_enable(RS485_1_CLOCK);gpio_mode_setup(RS485_1_EN_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, RS485_1_EN_PIN);rs485_1_rx_mode();
}/* ----------------------- Start implementation -----------------------------*/
void
vMBPortSerialEnable( BOOL xRxEnable, BOOL xTxEnable )
{/* If xRXEnable enable serial receive interrupts. If xTxENable enable* transmitter empty interrupts.*/if (xRxEnable) {rs485_delay(10000);rs485_1_rx_mode();rs485_delay(10000);usart_enable_rx_interrupt(USART1);}else {usart_disable_rx_interrupt(USART1);}if (xTxEnable) {rs485_delay(10000);rs485_1_tx_mode();rs485_delay(10000);usart_enable_tx_interrupt(USART1);}else {usart_disable_tx_interrupt(USART1);}
}BOOL
xMBPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity )
{nvic_enable_irq(NVIC_USART1_IRQ);rcc_periph_clock_enable(RCC_GPIOB);gpio_mode_setup(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO6 | GPIO7);gpio_set_af(GPIOB, GPIO_AF0, GPIO6 | GPIO7);rcc_periph_clock_enable(RCC_USART1);/* Set up USART/UART parameters using the libopencm3 helper functions */usart_set_baudrate(USART1, ulBaudRate);usart_set_databits(USART1, ucDataBits);usart_set_stopbits(USART1, USART_STOPBITS_1);usart_set_mode(USART1, USART_MODE_TX_RX);switch (eParity) {case MB_PAR_ODD:usart_set_parity(USART1, USART_PARITY_ODD);break;case MB_PAR_EVEN:usart_set_parity(USART1, USART_PARITY_EVEN);break;default:usart_set_parity(USART1, USART_PARITY_NONE);break;}usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);usart_enable(USART1);rs485_gpio_init();return TRUE;
}BOOL
xMBPortSerialPutByte( CHAR ucByte )
{usart_send_blocking(USART1, (uint16_t) ucByte);    return TRUE;
}BOOL
xMBPortSerialGetByte( CHAR * pucByte )
{*pucByte = usart_recv(USART1);return TRUE;
}uint32_t uart1_isr, uart1_icr;void usart1_isr(void)
{/* Check if we were called because of RXNE. */if (((USART_CR1(USART1) & USART_CR1_RXNEIE) != 0) &&((USART_ISR(USART1) & USART_ISR_RXNE) != 0)) {/* Retrieve the data from the peripheral. */// usart_recv(USART1);pxMBFrameCBByteReceived();}/* Check if we were called because of TXE. */if (((USART_CR1(USART1) & USART_CR1_TXEIE) != 0) &&((USART_ISR(USART1) & USART_ISR_TXE) != 0)) {/* Put data into the transmit register. *///usart_send(USART1, data);pxMBFrameCBTransmitterEmpty();}}

• porttimer

#include "port.h"#include 
#include 
#include /* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"/* ----------------------- static functions ---------------------------------*/
static void prvvTIMERExpiredISR( void );/* ----------------------- Start implementation -----------------------------*/
BOOL
xMBPortTimersInit( USHORT usTim1Timerout50us )
{rcc_periph_clock_enable(RCC_TIM2);nvic_enable_irq(NVIC_TIM2_IRQ);rcc_periph_reset_pulse(RST_TIM2);timer_set_mode(TIM2, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);timer_set_prescaler(TIM2, (rcc_apb1_frequency/ 20000));timer_disable_preload(TIM2);timer_continuous_mode(TIM2);timer_set_period(TIM2, usTim1Timerout50us);timer_enable_counter(TIM2);timer_enable_irq(TIM2, TIM_DIER_UIE);return TRUE;
}inline void
vMBPortTimersEnable(  )
{timer_set_counter(TIM2, 0);timer_enable_counter(TIM2);
}inline void
vMBPortTimersDisable(  )
{timer_disable_counter(TIM2);
}/* 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.*/
static void prvvTIMERExpiredISR( void )
{( void )pxMBPortCBTimerExpired(  );
}void
vMBPortTimersDelay( USHORT usTimeOutMS )
{vTaskDelay(pdMS_TO_TICKS(usTimeOutMS));
}void tim2_isr(void)
{if (timer_get_flag(TIM2, TIM_SR_UIF)) {/* Clear compare interrupt flag. */timer_clear_flag(TIM2, TIM_SR_UIF);prvvTIMERExpiredISR();}
}

开启定时器和中断，用于modbus时序控制；

2.3 使用

在src目录新建 modbus_cb.h 和 modbus_cb.c 两个文件，实现寄存器、线圈的读写回调：

/// CMD4
eMBErrorCode eMBRegInputCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs );/// CMD6、3、16
eMBErrorCode eMBRegHoldingCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs, eMBRegisterMode eMode );/// CMD1、5、15
eMBErrorCode eMBRegCoilsCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNCoils, eMBRegisterMode eMode );/// CMD4
eMBErrorCode eMBRegDiscreteCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNDiscrete );

基本的实现示例如下：

#include "modbus_cb.h"
#include "stdbool.h"extern log(const char* fmt, ...);// 输入寄存器
#define REG_INPUT_SIZE  32
uint16_t REG_INPUT_BUF[REG_INPUT_SIZE];// 保持寄存器
#define REG_HOLD_SIZE   32
uint16_t REG_HOLD_BUF[REG_HOLD_SIZE];// 线圈寄存器
#define REG_COILS_SIZE 16
uint8_t REG_COILS_BUF[REG_COILS_SIZE];// 离散量
#define REG_DISC_SIZE  8
uint8_t REG_DISC_BUF[REG_DISC_SIZE];/// CMD4
eMBErrorCode eMBRegInputCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs )
{USHORT usRegIndex = usAddress - 1; // 非法检测if((usRegIndex + usNRegs) > REG_INPUT_SIZE){return MB_ENOREG;}log(" CMD4, 寄存器输入.");// 填充数据REG_INPUT_BUF[0] = 0x01;REG_INPUT_BUF[1] = 0x02;// 循环读取while ( usNRegs > 0 ) {*pucRegBuffer++ = ( unsigned char )( REG_INPUT_BUF[usRegIndex] >> 8 );*pucRegBuffer++ = ( unsigned char )( REG_INPUT_BUF[usRegIndex] & 0xFF );usRegIndex++;usNRegs--;}return MB_ENOERR;
}/// CMD6、3、16
eMBErrorCode eMBRegHoldingCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs, eMBRegisterMode eMode )
{USHORT usRegIndex = usAddress - 1;  // 非法检测if((usRegIndex + usNRegs) > REG_HOLD_SIZE) {return MB_ENOREG;}log(" CMD3,6,16, 保持寄存器读写.");// 写寄存器if (eMode == MB_REG_WRITE) {while ( usNRegs > 0 ) {uint16_t value;value = (pucRegBuffer[0] << 8) | pucRegBuffer[1];log("  写寄存器值:%d", value);pucRegBuffer += 2;usRegIndex++;usNRegs--;}}// 读寄存器else {log("  读寄存器.");REG_HOLD_BUF[0] = 0x32;REG_HOLD_BUF[1] = 0x33;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
eMBErrorCode eMBRegCoilsCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNCoils, eMBRegisterMode eMode )
{USHORT usRegIndex   = usAddress - 1;USHORT usCoilGroups = ((usNCoils - 1) / 8 + 1);UCHAR  ucStatus     = 0;UCHAR  ucBits       = 0;UCHAR  ucDisp       = 0;// 非法检测if ((usRegIndex + usNCoils) > REG_COILS_SIZE) {return MB_ENOREG;}log("  CMD1,5,15, 线圈读写.");// 写线圈if (eMode == MB_REG_WRITE) {while (usCoilGroups--) {ucStatus = *pucRegBuffer++;ucBits   = 8;while((usNCoils) != 0 && (ucBits) != 0) {bool flag = ucStatus & 0x01;switch (usRegIndex) {case 0:log(" 线圈0 : %d", flag);//break;case 1:log(" 线圈1 : %d", flag);break;default:break;}usRegIndex++;ucStatus >>= 1;usNCoils--;ucBits--;}}}// 读线圈else {REG_COILS_BUF[0]  = 1;REG_COILS_BUF[1]  = 0;while (usCoilGroups--) {ucDisp = 0;ucBits = 8;ucStatus = 0;while((usNCoils) != 0 && (ucBits) != 0) {ucStatus |= (REG_COILS_BUF[usRegIndex++] << (ucDisp++));usNCoils--;ucBits--;}*pucRegBuffer++ = ucStatus;}}return MB_ENOERR;
}/// CMD4
eMBErrorCode eMBRegDiscreteCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNDiscrete )
{USHORT usRegIndex   = usAddress - 1;USHORT usCoilGroups = ((usNDiscrete - 1) / 8 + 1);UCHAR  ucStatus     = 0;UCHAR  ucBits       = 0;UCHAR  ucDisp       = 0;// 非法检测if ((usRegIndex + usNDiscrete) > REG_DISC_SIZE) {return MB_ENOREG;}log("  CMD4, 离散寄存器写入.");// 读离散输入while (usCoilGroups--) {ucDisp = 0;ucBits = 8;ucStatus = 0;while((usNDiscrete != 0) && (ucBits != 0)){switch (usRegIndex) {case 0:ucStatus = 0x10;break;}usRegIndex++;ucDisp++;usNDiscrete--;ucBits--;}*pucRegBuffer++ = ucStatus;}return MB_ENOERR;
}

在main中创建modbus任务：

static void task_modbus_handle(void *param)
{eMBErrorCode    eStatus;log("  task modbus start.");eStatus = eMBInit( MB_RTU, 0x01, 0, 9600, MB_PAR_NONE );/* Enable the Modbus Protocol Stack. */eStatus = eMBEnable();(void)eStatus;for( ;; ) {( void )eMBPoll();vTaskDelay(pdMS_TO_TICKS(10));}}

3 烧写测试

将开发板连接到USB转485模块，然后使用modbus poll程序进行测试：