//串口指令转换器程序，用于AT89C51
//2004-2-25

#include <AT89X51.H> 

//全局变量定义
bit flag_uart_busy;
unsigned char uartread,uartwrite; 
unsigned char uartbuf[8];
unsigned char urvcmd;//uart接收到的控制指令


#define cmd_north 51
#define cmd_south 52
#define cmd_dec_stop 53
#define cmd_east 54
#define cmd_west 55
#define cmd_ra_normal 56
#define cmd_ra_stop 57

#define cmdr_north 41
#define cmdr_south 42
#define cmdr_dec_stop 43
#define cmdr_east 44
#define cmdr_west 45
#define cmdr_ra_normal 46
#define cmdr_ra_stop 47

sbit pstp=P3^3;
sbit pn=P3^4;
sbit ps=P3^5;
sbit pe=P3^6;
sbit pw=P3^7;

//主程序

void main (void){

P3=0;

//延时
{unsigned int i;
	for(i=0;i<20000;i++){ //delay
		;}
	for(i=0;i<60000;i++){ //delay
		;}
	}

//初始化设置

//UART configuration
SCON = 0x50; // SCON: mode 1, 8-bit UART, enable rcvr 
TMOD|= 0x20; // TMOD: timer 1, mode 2, 8-bit reload 
TL1=0xFD; //9600 baud rate
TH1=0xFD; //9600 baud rate reload
TXD=1;
RXD=1;

//interrupt configuration
EA=1; 
ET1=0; //TIMER 1 disabled
ES=1; //UART enabled 


//开始定时
TR1=1;

uartread=0;
uartwrite=0; 

flag_uart_busy=0;


while (1) {

	if(uartread!=uartwrite){//有新数据
		if(++uartread>7) uartread=0;
		urvcmd=uartbuf[uartread];

		if(urvcmd>=192){
			P0=urvcmd;
			}
		else if(urvcmd>=128){
			P1=urvcmd;
			}
		else if(urvcmd>=64){
			P2=urvcmd;
			}
		else if(urvcmd<16){
			P3&=0x0F;
			P3|=(urvcmd*16);
			}
		else if(urvcmd<32){
			P2&=0xF0;
			P2|=(urvcmd-16);
			}
		else {	//32<=,<64
			switch(urvcmd){
				case cmd_ra_normal:
					pe=0;
					pw=0;	
					pstp=0;				
					break;
				case cmd_east:
					pw=0;
					pe=1;					
					break;		
				case cmd_west:
					pe=0;
					pw=1;					
					break;
				case cmd_dec_stop:
					pn=0;
					ps=0;					
					break;
				case cmd_north:
					ps=0;
					pn=1;					
					break;
				case cmd_south:
					pn=0;
					ps=1;					
					break;
				case cmd_ra_stop:
					pe=0;
					pw=0;
					pstp=1;
					break;
				case cmdr_ra_normal:
					pe=1;
					pw=1;	
					pstp=1;				
					break;
				case cmdr_east:
					pw=1;
					pe=0;					
					break;		
				case cmdr_west:
					pe=1;
					pw=0;					
					break;
				case cmdr_dec_stop:
					pn=1;
					ps=1;					
					break;
				case cmdr_north:
					ps=1;
					pn=0;					
					break;
				case cmdr_south:
					pn=1;
					ps=0;					
					break;
				case cmdr_ra_stop:
					pe=1;
					pw=1;
					pstp=0;
					break;

				default:
					break;
				}	//end of switvh
			} //end of if


		//ack
		while(flag_uart_busy){
			;}
		flag_uart_busy=1;
		SBUF=255-urvcmd;

		} //end of if

	} //end of while(1)

}


//中断处理程序



/***************************************************
uart interrupt
****************************************************/

void uart(void) interrupt 4 using 2{

if( TI){
TI=0;
}
if (RI){
if(++uartwrite>7) uartwrite=0;
uartbuf[uartwrite]=SBUF;
RI=0;
}
flag_uart_busy=0;
}