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352 lines
11 KiB
352 lines
11 KiB
1 week ago
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/*
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* modbus.c
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*
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* Created on: Jul 3, 2025
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* Author: shiyanlei
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*/
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#include "stm32g0xx_hal.h"
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#include <stdint.h>
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#include <stdbool.h>
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#include "main.h"
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#include "modbus.h"
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#include "usart.h"
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//uint16_t holdingRegisters[REGISTER_COUNT] = {0}; /*长度为10*/
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int16_t holdingRegisters[REGISTER_COUNT] = {0}; /*长度为10*/
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/* 寄存器可写标志位（1:可写，0:只读） */
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uint8_t registerWritable[REGISTER_COUNT] = {
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registerWritable_0, registerWritable_1, registerWritable_2, registerWritable_3,
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registerWritable_4, registerWritable_5, registerWritable_6, registerWritable_7,
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registerWritable_8, registerWritable_9
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};
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/* 全局变量 */
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uint8_t modbusBuffer[MODBUS_BUFFER_SIZE];
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//int8_t modbusBuffer[MODBUS_BUFFER_SIZE];
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uint16_t modbusBufferIndex = 0;
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uint32_t lastByteTime = 0;
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bool messageComplete = false;
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uint8_t response[256];
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/* 函数声明 */
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void Modbus_Init(void);
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void Modbus_Process(void);
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void Modbus_SendResponse(uint8_t *data, uint8_t length);
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void Modbus_HandleFunction03(uint16_t startAddress, uint16_t registerCount);
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void Modbus_HandleFunction06(uint16_t registerAddress, uint16_t value);
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void Modbus_HandleFunction10(uint16_t startAddress, uint16_t registerCount, uint8_t *data);
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void Modbus_SendExceptionResponse(uint8_t exceptionCode);
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uint16_t CalculateCRC(uint8_t *data, uint8_t length);
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/* 初始化函数 */
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void Modbus_Init(void)
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{
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/* RS485 方向控制引脚置为接收状态 */
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HAL_GPIO_WritePin(DIR_GPIO_Port, DIR_Pin, GPIO_PIN_RESET);
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/* 启动串口中断接收 */
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modbusBufferIndex = 0;
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HAL_UART_Receive_IT(&huart2, (uint8_t *)&modbusBuffer[modbusBufferIndex], 1);
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}
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/* Modbus处理函数 - 应在主循环中调用 */
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void Modbus_Process(void)
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{
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uint16_t startAddress = 0;
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uint16_t registerCount = 0;
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uint16_t value = 0;
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uint8_t byteCount = 0;
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uint16_t crcReceived;
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uint16_t crcCalculated;
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if (modbusBufferIndex > 0 && (HAL_GetTick() - lastByteTime) > MODBUS_TIMEOUT_MS)
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{
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/* 超时，标记消息完成 */
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messageComplete = true;
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}
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if (!messageComplete)
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{
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return;
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}
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/* 一个有效的 RTU 帧至少包含：地址 + 功能码 + 2 字节 CRC */
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if (modbusBufferIndex < 4)
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{
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modbusBufferIndex = 0;
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messageComplete = false;
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return;
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}
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crcReceived = (uint16_t)((modbusBuffer[modbusBufferIndex - 1] << 8) |
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modbusBuffer[modbusBufferIndex - 2]);
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crcCalculated = CalculateCRC(modbusBuffer, (uint8_t)(modbusBufferIndex - 2));
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if (MODBUS_CRC_OFF == 1 || crcReceived == crcCalculated)
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{
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if (modbusBuffer[0] == MODBUS_SLAVE_ADDRESS) /*ID 0x42*/
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{
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switch (modbusBuffer[1])
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{
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case MODBUS_FUNCTION_CODE_03:
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if (modbusBufferIndex >= 8)
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{
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startAddress = (uint16_t)((modbusBuffer[2] << 8) | modbusBuffer[3]);
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registerCount = (uint16_t)((modbusBuffer[4] << 8) | modbusBuffer[5]);
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Modbus_HandleFunction03(startAddress, registerCount);
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}
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break;
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case MODBUS_FUNCTION_CODE_06:
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if (modbusBufferIndex >= 8)
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{
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startAddress = (uint16_t)((modbusBuffer[2] << 8) | modbusBuffer[3]);
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value = (uint16_t)((modbusBuffer[4] << 8) | modbusBuffer[5]);
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Modbus_HandleFunction06(startAddress, value);
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}
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break;
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case MODBUS_FUNCTION_CODE_10:
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if (modbusBufferIndex >= 9)
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{
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startAddress = (uint16_t)((modbusBuffer[2] << 8) | modbusBuffer[3]);
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registerCount = (uint16_t)((modbusBuffer[4] << 8) | modbusBuffer[5]);
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byteCount = modbusBuffer[6];
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/* 检查数据长度是否正确 */
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if (byteCount == (uint8_t)(registerCount * 2U) &&
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(modbusBufferIndex - 2U) >= (uint16_t)(7U + byteCount))
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{
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Modbus_HandleFunction10(startAddress, registerCount, &modbusBuffer[7]);
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}
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else
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{
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Modbus_SendExceptionResponse(0x03);
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}
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}
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break;
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default:
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Modbus_SendExceptionResponse(0x01);
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break;
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}
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}
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}
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/* 重置缓冲区 */
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modbusBufferIndex = 0;
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messageComplete = false;
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}
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/* 处理功能码03 */
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void Modbus_HandleFunction03(uint16_t startAddress, uint16_t registerCount)
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{
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/* 检查地址和数量是否合法 */
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if ((startAddress + registerCount) > (REGISTER_START_ADDRESS + REGISTER_COUNT) ||
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registerCount > 0x7D)
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{
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Modbus_SendExceptionResponse(0x02);
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return;
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}
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uint8_t byteCount = (uint8_t)(registerCount * 2U);
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uint8_t index = 0;
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response[index++] = MODBUS_SLAVE_ADDRESS;
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response[index++] = MODBUS_FUNCTION_CODE_03;
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response[index++] = byteCount;
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for (uint16_t i = 0; i < registerCount; i++)
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{
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uint16_t regValue = holdingRegisters[(startAddress - REGISTER_START_ADDRESS) + i];
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response[index++] = (uint8_t)((regValue >> 8) & 0xFF);
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response[index++] = (uint8_t)(regValue & 0xFF);
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}
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uint16_t crc = CalculateCRC(response, index);
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response[index++] = (uint8_t)(crc & 0xFF);
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response[index++] = (uint8_t)((crc >> 8) & 0xFF);
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Modbus_SendResponse(response, index);
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}
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/* 处理功能码06 */
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void Modbus_HandleFunction06(uint16_t registerAddress, uint16_t value)
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{
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/* 检查地址是否合法 */
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if (registerAddress >= (REGISTER_START_ADDRESS + REGISTER_COUNT))
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{
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Modbus_SendExceptionResponse(0x02);
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return;
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}
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uint16_t regIndex = registerAddress - REGISTER_START_ADDRESS;
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uint16_t responseValue = holdingRegisters[regIndex];
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/* 只有可写寄存器才更新值 */
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if (registerWritable[regIndex] == 1)
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{
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holdingRegisters[regIndex] = value;
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responseValue = value;
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}
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/* 准备响应帧 - 功能码06的响应是原请求帧的原样返回 */
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uint8_t index = 0;
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response[index++] = MODBUS_SLAVE_ADDRESS;
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response[index++] = MODBUS_FUNCTION_CODE_06;
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response[index++] = (uint8_t)((registerAddress >> 8) & 0xFF);
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response[index++] = (uint8_t)(registerAddress & 0xFF);
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response[index++] = (uint8_t)((responseValue >> 8) & 0xFF);
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response[index++] = (uint8_t)(responseValue & 0xFF);
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/* 计算CRC并添加到响应帧 */
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uint16_t crc = CalculateCRC(response, index);
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response[index++] = (uint8_t)(crc & 0xFF);
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response[index++] = (uint8_t)((crc >> 8) & 0xFF);
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/* 发送响应 */
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Modbus_SendResponse(response, index);
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}
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/* 处理功能码0x10 */
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void Modbus_HandleFunction10(uint16_t startAddress, uint16_t registerCount, uint8_t *data)
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{
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/* 检查地址和数量是否合法 */
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if ((startAddress + registerCount) > (REGISTER_START_ADDRESS + REGISTER_COUNT) ||
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registerCount == 0 || registerCount > 0x7B)
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{
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Modbus_SendExceptionResponse(0x02);
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return;
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}
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/* 处理每个寄存器 */
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for (uint16_t i = 0; i < registerCount; i++)
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{
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uint16_t regIndex = (startAddress - REGISTER_START_ADDRESS) + i;
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uint16_t value = (uint16_t)((data[i * 2] << 8) | data[i * 2 + 1]);
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/* 只有可写寄存器才更新值 */
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if (registerWritable[regIndex] == 1)
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{
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holdingRegisters[regIndex] = value;
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}
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}
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/* 准备响应帧 - 功能码0x10的响应包含起始地址和写入数量 */
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uint8_t index = 0;
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response[index++] = MODBUS_SLAVE_ADDRESS;
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response[index++] = MODBUS_FUNCTION_CODE_10;
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response[index++] = (uint8_t)((startAddress >> 8) & 0xFF);
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response[index++] = (uint8_t)(startAddress & 0xFF);
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response[index++] = (uint8_t)((registerCount >> 8) & 0xFF);
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response[index++] = (uint8_t)(registerCount & 0xFF);
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/* 计算CRC并添加到响应帧 */
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uint16_t crc = CalculateCRC(response, index);
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response[index++] = (uint8_t)(crc & 0xFF);
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response[index++] = (uint8_t)((crc >> 8) & 0xFF);
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/* 发送响应 */
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Modbus_SendResponse(response, index);
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}
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/* 发送异常响应 */
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void Modbus_SendExceptionResponse(uint8_t exceptionCode)
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{
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response[0] = MODBUS_SLAVE_ADDRESS;
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response[1] = modbusBuffer[1] | 0x80;
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response[2] = exceptionCode;
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uint16_t crc = CalculateCRC(response, 3);
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response[3] = (uint8_t)(crc & 0xFF);
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response[4] = (uint8_t)((crc >> 8) & 0xFF);
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Modbus_SendResponse(response, 5);
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}
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/* 发送响应 */
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void Modbus_SendResponse(uint8_t *data, uint8_t length)
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{
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/* 使能RS485发送 */
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HAL_GPIO_WritePin(DIR_GPIO_Port, DIR_Pin, GPIO_PIN_SET);
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/* DMA 发送数据，发送完成后在 HAL_UART_TxCpltCallback 中切回接收 */
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HAL_UART_Transmit_DMA(&huart2, data, length);
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}
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/* CRC计算 */
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uint16_t CalculateCRC(uint8_t *data, uint8_t length)
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{
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uint16_t crc = 0xFFFF;
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for (uint8_t i = 0; i < length; i++)
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{
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crc ^= (uint16_t)data[i];
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for (uint8_t j = 0; j < 8; j++)
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{
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if ((crc & 0x0001) != 0)
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{
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crc >>= 1;
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crc ^= 0xA001;
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}
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else
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{
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crc >>= 1;
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}
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}
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}
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return crc;
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}
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/* UART接收中断回调函数 */
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void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
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{
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if (huart != &huart2)
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{
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return;
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}
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lastByteTime = HAL_GetTick();
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if (modbusBufferIndex < MODBUS_BUFFER_SIZE)
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{
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/* HAL 已经将接收到的字节写入 modbusBuffer[modbusBufferIndex]，
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此处只需向后移动索引。 */
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modbusBufferIndex++;
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}
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if (modbusBufferIndex < MODBUS_BUFFER_SIZE)
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{
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HAL_UART_Receive_IT(&huart2, (uint8_t *)&modbusBuffer[modbusBufferIndex], 1);
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}
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else
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{
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/* 缓冲区满，丢弃并等待下一帧 */
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modbusBufferIndex = 0;
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HAL_UART_Receive_IT(&huart2, (uint8_t *)&modbusBuffer[modbusBufferIndex], 1);
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}
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}
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/* UART发送完成回调：切回RS485接收方向 */
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void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
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{
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if (huart == &huart2)
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{
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HAL_GPIO_WritePin(DIR_GPIO_Port, DIR_Pin, GPIO_PIN_RESET);
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}
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}
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/* UART错误回调：重新同步接收 */
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void HAL_UART_ErrorCallback(UART_HandleTypeDef *huart)
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{
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if (huart == &huart2)
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{
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modbusBufferIndex = 0;
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HAL_UART_Receive_IT(&huart2, (uint8_t *)&modbusBuffer[modbusBufferIndex], 1);
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}
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}
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