STM8S003单片机modbus协议简单通信示例

#include "modbus.h" #include "crc16.h" #include "uart.h" extern u8 ReceiveBuf[MaxDataLen]; extern u8 RecIndexLen; u8 SendBuf[MaxDataLen] = {0}; u16 StartRegAddr = 0; u8 err = 0; //错误代码 u8 HoldReg[16] = {1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8}; //存储8路输出功率值 /* 错误代码说明: 0x01 不是支持的功能码 0x02 起始地址不在规定范围内 0x03 寄存器数量不在规定范围内 0x04 数据校验错误 */ //处理接收到的数据 // 接收: [地址][功能码][起始地址高][起始地址低][总寄存器数高][总寄存器数低][CRC低][CRC高] void DisposeReceive( void ) { u16 CRC16 = 0, CRC16Temp = 0; if( ReceiveBuf[0] == SlaveID ) //地址等于本机地址 地址范围:1 - 32 { CRC16 = App_Tab_Get_CRC16( ReceiveBuf, RecIndexLen - 2 ); //CRC校验 低字节在前 高字节在后 高字节为报文最后一个字节 CRC16Temp = ( ( u16 )( ReceiveBuf[RecIndexLen - 1] << 8 ) | ReceiveBuf[RecIndexLen - 2] ); if( CRC16 != CRC16Temp ) { err = 4; //CRC校验错误 } StartRegAddr = ( u16 )( ReceiveBuf[2] << 8 ) | ReceiveBuf[3]; if( StartRegAddr > 0x07 ) { err = 2; //起始地址不在规定范围内 00 - 07 1 - 8号通道 } if( err == 0 ) { switch( ReceiveBuf[1] ) //功能码 { case 3: //读多个寄存器 { Modbus_03_Slave(); break; } case 6: //写单个寄存器 { Modbus_06_Slave(); break; } case 16: //写多个寄存器 { Modbus_16_Slave(); break; } default: { err = 1; //不支持该功能码 break; } } } if( err > 0 ) { SendBuf[0] = ReceiveBuf[0]; SendBuf[1] = ReceiveBuf[1] | 0x80; SendBuf[2] = err; //发送错误代码 CRC16Temp = App_Tab_Get_CRC16( SendBuf, 3 ); //计算CRC校验值 SendBuf[3] = CRC16Temp & 0xFF; //CRC低位 SendBuf[4] = ( CRC16Temp >> 8 ); //CRC高位 Uart1_Send( SendBuf, 5 ); err = 0; //发送完数据后清除错误标志 } } } /* 函数功能：读保持寄存器 03 主站请求报文: 0x01 0x03 0x0000 0x0001 0x840A 读从0开始的1个保持寄存器 从站正常响应报文: 0x01 0x03 0x02 0x09C4 0xBF87 读到的2字节数据为 0x09C4 */ void Modbus_03_Slave( void ) { u16 RegNum = 0; u16 CRC16Temp = 0; u8 i = 0; RegNum = ( u16 )( ReceiveBuf[4] << 8 ) | ReceiveBuf[5]; //获取寄存器数量 if( ( StartRegAddr + RegNum ) < 9 ) //寄存器地址+寄存器数量 在规定范围内 { SendBuf[0] = ReceiveBuf[0]; SendBuf[1] = ReceiveBuf[1]; SendBuf[2] = RegNum * 2; for( i = 0; i < RegNum; i++ ) //读取保持寄存器内的值 { SendBuf[3 + i * 2] = HoldReg[StartRegAddr * 2 + i * 2]; SendBuf[4 + i * 2] = HoldReg[StartRegAddr * 2 + i * 2 + 1]; } CRC16Temp = App_Tab_Get_CRC16( SendBuf, RegNum * 2 + 3 ); //获取CRC校验值 SendBuf[RegNum * 2 + 3] = CRC16Temp & 0xFF; //CRC低位 SendBuf[RegNum * 2 + 4] = ( CRC16Temp >> 8 ); //CRC高位 Uart1_Send( SendBuf, RegNum * 2 + 5 ); } else { err = 3; //寄存器数量不在规定范围内 } } /* 函数功能:写单个保持寄存器 06 主站请求报文: 0x01 0x06 0x0000 0x1388 0x849C 写0号寄存器的值为0x1388 从站正常响应报文: 0x01 0x06 0x0000 0x1388 0x849C 0号寄存器的值为0x1388 */ void Modbus_06_Slave( void ) { u16 RegValue = 0; u16 CRC16Temp = 0; RegValue = ( u16 )( ReceiveBuf[4] << 8 ) | ReceiveBuf[5]; //获取寄存器值 if( RegValue < 1001 ) //寄存器值不超过1000 { HoldReg[StartRegAddr * 2] = ReceiveBuf[4]; //存储寄存器值 HoldReg[StartRegAddr * 2 + 1] = ReceiveBuf[5]; SendBuf[0] = ReceiveBuf[0]; SendBuf[1] = ReceiveBuf[1]; SendBuf[2] = ReceiveBuf[2]; SendBuf[3] = ReceiveBuf[3]; SendBuf[4] = ReceiveBuf[4]; SendBuf[5] = ReceiveBuf[5]; CRC16Temp = App_Tab_Get_CRC16( SendBuf, 6 ); //获取CRC校验值 SendBuf[6] = CRC16Temp & 0xFF; //CRC低位 SendBuf[7] = ( CRC16Temp >> 8 ); //CRC高位 Uart1_Send( SendBuf, 8 ); } else { err = 3; //寄存器数值不在规定范围内 } } /* 函数功能:写多个连续保持寄存器值 16 主站请求报文: 0x01 0x10 0x7540 0x0002 0x04 0x0000 0x2710 0xB731 写从0x7540地址开始的2个保持寄存器值 共4字节 从站正常响应报文: 0x01 0x10 0x7540 0x0002 0x5A10 写从0x7540地址开始的2个保持寄存器值 */ void Modbus_16_Slave( void ) { u16 RegNum = 0; u16 CRC16Temp = 0; u8 i = 0; RegNum = ( u16 )( ReceiveBuf[4] << 8 ) | ReceiveBuf[5]; //获取寄存器数量 if( ( StartRegAddr + RegNum ) < 9 ) //寄存器地址+寄存器数量 在规定范围内 { for( i = 0; i < RegNum; i++ ) //存储寄存器设置值 { HoldReg[StartRegAddr * 2 + i * 2] = ReceiveBuf[i * 2 + 7]; HoldReg[StartRegAddr * 2 + 1 + i * 2] = ReceiveBuf[i * 2 + 8]; } SendBuf[0] = ReceiveBuf[0]; SendBuf[1] = ReceiveBuf[1]; SendBuf[2] = ReceiveBuf[2]; SendBuf[3] = ReceiveBuf[3]; SendBuf[4] = ReceiveBuf[4]; SendBuf[5] = ReceiveBuf[5]; CRC16Temp = App_Tab_Get_CRC16( SendBuf, 6 ); //获取CRC校验值 SendBuf[6] = CRC16Temp & 0xFF; //CRC低位 SendBuf[7] = ( CRC16Temp >> 8 ); //CRC高位 Uart1_Send( SendBuf, 8 ); } else { err = 3; //寄存器数量不在规定范围内 } }