spi_receive.c

51单片机SPI模式

#include "reg52.h"

#define uchar unsigned char
#define uint  unsigned int 

//-------------------------//
sbit SPISCLK =P1^0;
sbit MOSI	 =P1^1;
sbit MISO    =P1^2;
sbit CS		 =P1^3;

sbit P20=P2^0;	 //选通数码管
sbit P21=P2^1;

//------------------------//

void Nop()
{
	;
}
void delay(uchar t)
{
	while(t--){;}
}

uchar SPI_Receive(void)
{
	uchar i,dat=0,temp;
	bit flag;
	SPISCLK=1;
	MISO=1;
	CS=0;//选中器件
	Nop();
	Nop();
	for(i=0;i<8;i++)
		{
			SPISCLK=1;
			Nop();
			Nop();
			Nop();
			SPISCLK=0;
			
			Nop();
			Nop();

			flag=MISO;
			if(flag) temp=0x01;
			else temp=0x00;
			dat=(dat<<1);				
			dat=(dat|temp);		
		}

		CS=1;
		SPISCLK=1;
		return dat;
}

void main()
{
	uchar udat;
	uchar i=0;
	uchar	code table[10]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,
                          0x7F,0x6F};
//	P20=0;
//	P21=1;
	while(1)
		{
			udat=SPI_Receive();
			P2=0xfe;
			P0=table[udat%10];
			for(i=0;i<200;i++)
			delay(500);

			P2=0xfd;
			P0=table[udat/10];
			for(i=0;i<200;i++)
			delay(500);
		}
}