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/* YW-201射频卡模块uart通信例程 http://www.youwokeji.com.cn 89S52 */ #include <reg52.h> #include <intrins.h> unsigned char idata g_cReceiveBuffer[70]; //和上位机通讯时的缓冲区 unsigned char g_cReceiveCounter = 0; //接收到上位机的字节数 unsigned char g_cCheckSum; //串口校验 bit g_bReceived0x10Flag; //是否接收到0x10 bit g_bPackageStarted; //包接收是否开始 bit g_bReceiveOK; //正确接收到上位机指令标志 bit g_bReceivePackageStart; /***************************************************************************** *功能：正确执行完上位机指令，应答 *入口： * DataLEN = 数据域长度 *注意：1、从g_cReceiveBuffer[3] 开始是应答数据块，所以调用前将所有数据写入 从g_cReceiveBuffer[3] 开始的地方 2、status是应答状态位 *****************************************************************************/ void Answer(unsigned char DataLEN, char Status) { unsigned char CheckSum = 0; unsigned char i; g_cReceiveBuffer[0] = DataLEN+4; //g_cReceiveBuffer[1]为命令字节 g_cReceiveBuffer[2] = Status; ES = 0; SendByte(0x02); // 发送起始字符 for (i=0; i<DataLEN+3; i++) { if ((g_cReceiveBuffer[i] == 0x02) || (g_cReceiveBuffer[i] == 0x03) || (g_cReceiveBuffer[i] == 0x10)) { SendByte(0x10); } SendByte(g_cReceiveBuffer[i]); CheckSum ^= g_cReceiveBuffer[i]; } if ((CheckSum == 0x02) || (CheckSum == 0x03) || (CheckSum == 0x10)) { SendByte(0x10); } SendByte(CheckSum); SendByte(0x03); ES=1; } //发送单个字节 void SendByte(unsigned char i) { TI=0; SBUF=i; while(!TI); TI=0; } /***************************************************************************** *功能：串行中断，接收上位机数据 *说明： g_cReceiveBuffer[0] ＝ 长度字节 g_cReceiveBuffer[1] ＝ 命令字节 g_cReceiveBuffer[2～(g_cReceiveCounter-2)] ＝ 数据字节 g_cReceiveBuffer[g_cReceiveCounter-1] ＝ 校验字节 *****************************************************************************/ void seri_int () interrupt 4 using 1 { static unsigned char data i; unsigned char j; if(RI) { i = SBUF; RI = 0; if(!g_bReceiveOK) //接收该包数据 { if((0x02 == i) && (0 == g_bReceived0x10Flag)) { g_bPackageStarted = 1; g_cReceiveCounter = 0; g_cCheckSum = 0; } else if((0x03 == i) && (0 == g_bReceived0x10Flag) && (g_bPackageStarted)) //package end { g_bPackageStarted = 0; if ((g_cReceiveCounter > 1) && (g_cReceiveCounter < sizeof(g_cReceiveBuffer)+1)) { g_cCheckSum = 0; for(j=0; j<g_cReceiveCounter; j++) { g_cCheckSum ^= g_cReceiveBuffer[j]; } if((g_cCheckSum == 0)&&(g_cReceiveBuffer[0] == g_cReceiveCounter)) { g_bReceiveOK = 1; ES = 0; } else { g_bPackageStarted = 0; g_cReceiveCounter = 0; } } } else if((0x10 == i) && (0 == g_bReceived0x10Flag)) { g_bReceived0x10Flag = 1; } else if(g_bPackageStarted) { g_bReceived0x10Flag = 0; if(g_cReceiveCounter < sizeof(g_cReceiveBuffer)) { g_cReceiveBuffer[g_cReceiveCounter++] = i; } else { g_bPackageStarted = 0; //标准串口接收包起始标志 g_cReceiveCounter = 0; g_cCheckSum = 0; } } else { g_bReceived0x10Flag = 0; } } } }