usart.rar_atmega16

#include <iom16v.h> #include <macros.h> //起始字为0XAA，结束字为0XFF，系统接收的命令字为0XBB #define U_BEGIN 0xAA #define U_END 0xFF #define JIAOYAN 0xF0 #define R_NUM 0x00 #define E_NUM 0x01 unsigned long baud=9600; unsigned long crystal=8000000; unsigned int baud_set=0; void delay_us(unsigned int time) { do{ time--; } while(time>1); } void delay_ms(unsigned int time) { while(time!=0) { delay_us(500); time--; } } void display(unsigned char pin) {PORTC=pin; delay_ms(4000); } #define TX_BUFSIZE 4 unsigned char tx_buf[TX_BUFSIZE]; unsigned char tx_wrindex=0,tx_rdindex=0,tx_counter=0; #pragma interrupt_handler usart_tx_isr:14 void usart_tx_isr() { if(tx_counter) {--tx_counter; UDR=tx_buf[tx_rdindex]; if(++tx_rdindex==TX_BUFSIZE) tx_rdindex=0; } } void putchar(unsigned char c) {while(tx_counter==TX_BUFSIZE) ; CLI(); if(tx_counter||(UCSRA&(1<<UDRE)==0))//发送缓冲器是否为空，不为空，先放在缓存中 {tx_buf[tx_wrindex]=c; if(++tx_wrindex==TX_BUFSIZE) tx_wrindex=0; ++tx_counter;} else UDR=c; SEI(); } #define RX_BUFSZIE 4 unsigned char rx_buf[RX_BUFSZIE]; unsigned char rx_counter; int u_rflag=0; #pragma interrupt_handler usart_rx_isr:12 void usart_rx_isr() {unsigned char status,data; status=UCSRA; data=UDR; if(!u_rflag) { if((status&((1<<FE)|(1<<DOR)|(1<<PE)))==0) {rx_buf[rx_counter]=data; rx_counter++; switch(rx_counter) {case 1: if(data!=U_BEGIN) rx_counter=0; break; case 3: if(data!=(rx_buf[1]&JIAOYAN)) rx_counter=0; break; case 4: rx_counter=0; if(data==U_END) u_rflag=1; break;} } } } /*端口初始化*/ void port_init() {baud_set=(crystal/baud*16)-1; SREG=0x00; DDRC=0xFF; PORTC=0xFF; DDRA=0xFF; PORTA=0x00; } void usart_init() { UCSRA=0x00; UBRRH=(unsigned char)(baud_set>>8); UBRRL=(unsigned char)baud_set; UCSRB=((1<<RXEN)|(1<<TXEN)|(1<<TXCIE)|(1<<RXCIE)); UCSRC=((1<<URSEL)|(3<<UCSZ0)); } void main() { unsigned char tx1,tx2; port_init(); usart_init(); SREG = 0x80; //使能全局中断 while(1) {if(u_rflag) {tx1=R_NUM; if(rx_buf[1]!=0xBB) tx1=E_NUM; tx2=tx1&JIAOYAN; putchar(U_BEGIN); putchar(tx1); putchar(tx2); putchar(U_END); display(rx_buf[1]); u_rflag=0;} } }