[8051]設計簡單的通訊協定以POS機串接的通訊為例

參考教材：單晶片微處理機實習，黃嘉輝，台科大出版

前一篇文章：偵測通訊狀態，顯示連線/斷線和秒數

POS機串接的通訊格式：通訊規格

程式碼：

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#include <regx51.h> #define STX 0x02 #define ETX 0x03 unsigned char SendBuf[]="51015100peanut10"; unsigned char ReceiveBuf[16]; int receive_cnt=0; unsigned char buf; int count=1000; //1秒=1000*1ms int on_line_sec=0; //連線秒數 int on_line_status=0; //onlne or offline int is_receive=0; //是否有接收 // 使用函數的設定區 extern void LCD_Init(void); extern void LCD_Out(unsigned char x, unsigned char y, unsigned char *text); extern void LCD_Out_Cp(unsigned char *text); extern void LCD_Chr(unsigned char x, unsigned char y, unsigned char c); extern void LCD_Chr_Cp(unsigned char c); extern void LCD_Cmd(unsigned char cmd); extern void LCD_GotoXY(unsigned char x, unsigned char y); // 使用命令的設定區 extern unsigned char LCD_CURSOR_ON; extern unsigned char LCD_CURSOR_OFF; extern unsigned char LCD_CLEAR; void init_UART(unsigned int baudrate) { SCON=0x52; TMOD=0x20; TH1=256-((11059200/384)/baudrate); TL1=TH1; TR1=1; } void T0_int(void) interrupt 1 { TL0=(8192-1000)%32; //重設設定值 TH0=(8192-1000)/32; if(count==0) //連線已經有1秒了嗎? { if(on_line_status) { on_line_sec++; on_line_sec%=100; LCD_Chr(2,16, on_line_sec%10+0x30); //將接收到的資料送往顯示 LCD_Chr(2,15, on_line_sec/10+0x30); //將接收到的資料送往顯示 } if(!is_receive) { LCD_Cmd(LCD_CLEAR); LCD_Out(2,1,"offline"); on_line_status=0; on_line_sec=0; } is_receive=0; count=1000; //1秒count } else count--; //count每1ms減1 } void UART_int(void) interrupt 4 //串列中斷函式 { if(RI==1) //是不為接收中斷? { RI=0; //完成後清除RI buf=SBUF; //將接到的資料給buf if(buf == 0x02) receive_cnt=0; else if (buf == 0x03) LCD_Out(1,1,ReceiveBuf); else ReceiveBuf[receive_cnt++]=buf; is_receive=1; if(!on_line_status){ on_line_sec=0; on_line_status=1; LCD_Out(2,1,"online "); count=1000; } } else TI=0; //如果是傳送中斷，則清除TI，下次才方再傳送 } void Delay_ms(unsigned int count) //延遲count*1ms函式 { unsigned int i,j; for(i=0;i<count;i++) for(j=0;j<123;j++); } void main(void) { unsigned int i; init_UART(9600); //設定串列傳輸模式-9600bps ES=1; //開啟串列中斷 ET0=1; //啟動計時器1 EA=1; //開啟總中斷 TR0=1; //啟動計時器 LCD_Init(); // LCD 初始化 LCD_Cmd(LCD_CURSOR_ON); // 將游標打開 LCD_Chr(1,7,'8'); // LCD 在(1,7)位置顯示8 LCD_Chr_Cp('0'); // LCD 在(1,8)位置顯示0 LCD_Out_Cp("51"); // LCD 在(1,9)位置顯示51 LCD_Cmd(LCD_CURSOR_OFF); // 將游標關閉 LCD_Out(1,1," "); LCD_Out(2,1,"offline"); // LCD 在(2,1)位置顯示offline LCD_Out(2,15,"00"); while(1) { SBUF=STX; Delay_ms(10); for(i=0;i<16;i++) { SBUF=SendBuf[i]; //傳送0-9 Delay_ms(10); } SBUF=ETX; Delay_ms(10); Delay_ms(1000); } }

執行結果：