key_scanf.c

此程序是基于c8051f020平台实现的是等精度频率计的测量控制部分

#include <c8051f020.h>
#include "hao.h"
                
uchar key_scanf()
{
  uchar temp,num;    
	    P1=0xfe;
		temp=P1;
		temp=temp&0xf0;
		if(temp!=0xf0)
		 {
			delay(50);
			if(temp!=0xf0)
			 {
				switch(temp)
				{
					case 0xe0: num=0;
						break;
					case 0xd0: num=1;
						break;
					case 0xb0: num=2;
						break;
					case 0x70: num=3;
						break;
						
				
				}
				while(temp!=0xf0)
				{
				 	temp = P1;
					temp = temp&0xf0;
				}
			
			 }
		 }

		P1=0xfd;
		temp=P1;
		temp=temp&0xf0;
		if(temp!=0xf0)
		 {
			delay(50);
			if(temp!=0xf0)
			 {
				switch(temp)
				{
					case 0xe0: num=4;
						break;
					case 0xd0: num=5;
						break;
					case 0xb0: num=6;
						break;
					case 0x70: num=7;
						break;
				
				}
			   	while(temp!=0xf0)
				{
				 	temp = P1;
					temp = temp&0xf0;
					}
			 }
			
		 }

		P1=0xfb;
		temp=P1;
		temp=temp&0xf0;
		if(temp!=0xf0)
		 {
			delay(50);
			if(temp!=0xf0)
			 {
				switch(temp)
				{
					case 0xe0: num=8;
						break;
					case 0xd0: num=9;
						break;
					case 0xb0: num=10;
						break;
					case 0x70: num=11;
						break;
				
				}
			   	while(temp!=0xf0)
				{
				 	temp = P1;
					temp = temp&0xf0;
				}
			 }
			
		 }

		P1=0xf7;
		temp=P1;
		temp=temp&0xf0;
		if(temp!=0xf0)
		 {
			delay(50);
			if(temp!=0xf0)
			 {
				switch(temp)
				{
					case 0xe0: num=12;
						break;
					case 0xd0: num=13;
						break;
					case 0xb0: num=14;
						break;
					case 0x70: num=15;
						break;
				
				}
					while(temp!=0xf0)
				{
				 	temp = P1;
					temp = temp&0xf0;
			    }
			
		 }
		 }
		 return num;
}