/***************************Lcd1602.c文件程序源代碼*****************************/
（此處省略，可參考之前章節(jié)的代碼）
/****************************RS485.c文件程序源代碼*****************************/
（此處省略，可參考之前章節(jié)的代碼）
/****************************CRC16.c文件程序源代碼****************************/
/* CRC16計(jì)算函數(shù)，ptr-數(shù)據(jù)指針，len-數(shù)據(jù)長(zhǎng)度，返回值-計(jì)算出的CRC16數(shù)值 */
unsigned int GetCRC16(unsigned char *ptr, unsigned char len)
{
unsigned int index;
unsigned char crch = 0xFF; //高CRC字節(jié)
unsigned char crcl = 0xFF; //低CRC字節(jié)
unsigned char code TabH[] = { //CRC高位字節(jié)值表
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
} ;
unsigned char code TabL[] = { //CRC低位字節(jié)值表
0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,
0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
0x43, 0x83, 0x41, 0x81, 0x80, 0x40
} ;
while (len--) //計(jì)算指定長(zhǎng)度的CRC
{
index = crch ^ *ptr++;
crch = crcl ^ TabH[index];
crcl = TabL[index];
}
return ((crch<<8) | crcl);
}
關(guān)于CRC校驗(yàn)的算法，如果不是專(zhuān)門(mén)學(xué)習(xí)校驗(yàn)算法本身，大家可以不去研究這個(gè)程序的細(xì)節(jié)，直接使用現(xiàn)成的函數(shù)即可。
/*****************************main.c文件程序源代碼******************************/
#include
sbit BUZZ = P1^6;
bit flagBuzzOn = 0; //蜂鳴器啟動(dòng)標(biāo)志
unsigned char T0RH = 0; //T0重載值的高字節(jié)
unsigned char T0RL = 0; //T0重載值的低字節(jié)
unsigned char regGroup[5]; //Modbus寄存器組，地址為0x00～0x04
void ConfigTimer0(unsigned int ms);
extern void UartDriver();
extern void ConfigUART(unsigned int baud);
extern void UartRxMonitor(unsigned char ms);
extern void UartWrite(unsigned char *buf, unsigned char len);
extern unsigned int GetCRC16(unsigned char *ptr, unsigned char len);
extern void InitLcd1602();
extern void LcdShowStr(unsigned char x, unsigned char y, unsigned char *str);
void main()
{
EA = 1; //開(kāi)總中斷
ConfigTimer0(1); //配置T0定時(shí)1ms
ConfigUART(9600); //配置波特率為9600
InitLcd1602(); //初始化液晶
while (1)
{
UartDriver(); //調(diào)用串口驅(qū)動(dòng)
}
}
/* 串口動(dòng)作函數(shù)，根據(jù)接收到的命令幀執(zhí)行響應(yīng)的動(dòng)作
buf-接收到的命令幀指針，len-命令幀長(zhǎng)度 */
void UartAction(unsigned char *buf, unsigned char len)
{
unsigned char i;
unsigned char cnt;
unsigned char str[4];
unsigned int crc;
unsigned char crch, crcl;
if (buf[0] != 0x01) // 本機(jī)從地址設(shè)定為0x01，
{ //如數(shù)據(jù)幀中的地址字節(jié)與本機(jī)地址不符，
return; //則直接退出，即丟棄本幀數(shù)據(jù)不做任何處理
}
//地址相符時(shí)，再對(duì)本幀數(shù)據(jù)進(jìn)行校驗(yàn)
crc = GetCRC16(buf, len-2); //計(jì)算CRC校驗(yàn)值
crch = crc >> 8;
crcl = crc & 0xFF;
if ((buf[len-2]!=crch) || (buf[len-1]!=crcl))
{
return; //如CRC校驗(yàn)不符時(shí)直接退出
}
//地址和校驗(yàn)字均相符后，解析功能碼，執(zhí)行相關(guān)操作
switch (buf[1])
{
case 0x03: //讀取一個(gè)或連續(xù)的寄存器
if ((buf[2]==0x00) && (buf[3]<=0x05)) //只支持0x0000～0x0005
{
if (buf[3] <= 0x04) // 01 03 [ 00 i ] [ xx cnt ] [ crch crcl ]
{
i = buf[3]; //提取寄存器地址
cnt = buf[5]; //提取待讀取的寄存器數(shù)量
buf[2] = cnt*2; //讀取數(shù)據(jù)的字節(jié)數(shù)，為寄存器數(shù)*2
len = 3; //幀前部已有地址、功能碼、字節(jié)數(shù)共3個(gè)字節(jié)
while (cnt--)
{
buf[len++] = 0x00; //寄存器高字節(jié)補(bǔ)0
buf[len++] = regGroup[i++]; //寄存器低字節(jié)
}
}
else //地址>=0x05為蜂鳴器狀態(tài)
{
buf[2] = 2; //讀取數(shù)據(jù)的字節(jié)數(shù)
buf[3] = 0x00;
buf[4] = flagBuzzOn;
len = 5;
}
break;
}
else //寄存器地址不被支持時(shí)，返回錯(cuò)誤碼
{
buf[1] = 0x83; //功能碼最高位置1
buf[2] = 0x02; //設(shè)置異常碼為02-無(wú)效地址
len = 3;
break;
}
case 0x06: //寫(xiě)入單個(gè)寄存器
if ((buf[2]==0x00) && (buf[3]<=0x05)) //只支持0x0000～0x0005
{
if (buf[3] <= 0x04) // 01 06 [ 00 i ] [ xx regG ] [ crch crcl ]
{
i = buf[3]; //提取寄存器地址
regGroup = buf[5]; //保存寄存器數(shù)據(jù)
cnt = regGroup >> 4; //顯示到液晶上 16進(jìn)制轉(zhuǎn)string
if (cnt >= 0xA)
str[0] = cnt - 0xA + 'A';
else
str[0] = cnt + '0';
cnt = regGroup & 0x0F;
if (cnt >= 0xA)
str[1] = cnt - 0xA + 'A';
else
str[1] = cnt + '0';
str[2] = '';
LcdShowStr(i*3, 0, str);
}
else //地址0x05為蜂鳴器狀態(tài) // 01 06 [ 00 05 ] [ xx on ] [ crch crcl ]
{
flagBuzzOn = (bit)buf[5]; //寄存器值轉(zhuǎn)為蜂鳴器的開(kāi)關(guān)
}
len -= 2; //長(zhǎng)度-2以重新計(jì)算CRC并返回原幀
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