Uart.rar_51 uart _51串口收发_uart收发测试

/* * FileName: uart.c * Description: Implementation of SerialPort * Author: SangWei, HUST-CEEE-2004 * Contact: swkyer@163.com, swkyer@hotmail.com * Date: 2005-09-22 * * Platform: STC89C52(STC), KeilC51(ver: 7.20) * * (C)All Rights Reserved. */ #include <intrins.h> #include <REGX52.h> #include "uart.h" static unsigned char idata uartbuf; static unsigned char idata bufwptr, bufrptr; unsigned char idata uartbuff[UARTBUFFLEN]; /* 波特率设置表(22.1184MHZ), 4800, 9600, 19200, 38400, 57600, 115200 */ //static unsigned char code BAUD[] = {0x70, 0xB8, 0xDC, 0xEE, 0xF4, 0xFA}; /* 波特率设置表(11.0592MHZ), 4800, 9600, 19200, 38400, 57600, 115200 */ static unsigned char code BAUD[] = {0xB8, 0xDC, 0xEE, 0xF7, 0xFA, 0xFD}; /* * 初始化串口, 波特率57600 */ void UartInit(unsigned char baudrate) { ES = 0; TR2 = 0; bufwptr = 0; // 写指针 bufrptr = 0; // 读指针 PCON = 0x00; // 设置串口波特率, 时钟频率30MHZ T2CON = 0x30; // 定时器2作为波特率发生器 SCON = 0x50; // 模式1 // n = 65536 - [fosc/baud*32] // n = 65536 - 22118400/(57600*32) = 65536 - 12 = 65524 = 0xfff4 RCAP2H = 0xff; RCAP2L = BAUD[baudrate]; // baud rate 57600 TH2 = 0xff; TL2 = BAUD[baudrate]; IP = 0x10; // 串口中断优先级高 REN = 1; TI = 0; RI = 0; TR2 = 1; // 启动定时器2 ES = 1; // 使能串口中断 } /* * 发送一个字节数据 */ void SendChar(unsigned char ch) { SBUF = ch; while(TI == 0); TI = 0; } /* * 发送字符串 */ void SendString(char *str) { while(*str) { SendChar(*str); str++; } } /* * 判断是否接收到数据，如果没有返回0，如果有，返回数据长度 */ unsigned char IsUartReceived(void) { unsigned char num; EA = 0; // 关中断 if(bufwptr == bufrptr) num = 0; else if(bufwptr > bufrptr) num = (bufwptr-bufrptr); else // if(bufwptr < bufrptr) num = (UARTBUFFLEN-bufwptr+bufrptr); EA = 1; return num; } /* * 从缓冲区中读一个字节数据 * 返回剩下的字节数 */ unsigned char ReadChar(unsigned char idata *buf) { unsigned char ch, num; EA = 0; if(bufwptr == bufrptr) { *buf = 0; num = 0; } else if(bufwptr > bufrptr) { ch = uartbuff[bufrptr]; *buf = ch; bufrptr++; num = (bufwptr-bufrptr); } else // if(bufwptr < bufrptr) { ch = uartbuff[bufrptr]; *buf = ch; bufrptr++; if(bufrptr == UARTBUFFLEN) bufrptr = 0; num = (UARTBUFFLEN-bufrptr+bufwptr); } EA = 1; return num; } /* * 串口中断接受 */ void UartInt(void) interrupt 4 using 1 { if(RI) { ES = 0; uartbuf = SBUF; RI = 0; // 清中断标志 uartbuff[bufwptr] = uartbuf; // 数据写入缓冲区 if(bufwptr >= UARTBUFFLEN-1) // 循环缓冲指针 bufwptr = 0; else bufwptr++; if(bufwptr == bufrptr) // 未读数据被覆盖，读指针更新到写指针的上一个单元 bufrptr = bufwptr + 1; ES = 1; } }