kdscan.h

键盘扫描加数码管扫描显示综合应用 C语言函数

/*******************************管脚定义*****************************************/
#define PKEY P2
#define PDISPLAY P0 

/*******************************外部函数*************************************/
unsigned char KeyboardScan(void);
void DisplayScan(unsigned char displaydata[]);

/*******************************KeyboardScan*******************************/

unsigned char code ValueTable[]={0x7e,0x7d,0x7b,0x77,0xbe,0xbd,0xbb,0xb7,0xde,0xdd,0xdb,0xd7,0xee,0xed,0xeb,0xe7};

unsigned char KeyboardScan(void)
{
	unsigned char COL=0x04;
	unsigned char ROW=0x04;
	unsigned char SCANCODE=0x10;
	unsigned char RTNCODE;
	unsigned char KEYVALUE;
	while(1)
	{
		PKEY=~SCANCODE;
		RTNCODE=PKEY;
		KEYVALUE=(ROW-1)*4+COL-1;
		if(RTNCODE==ValueTable[KEYVALUE]) return KEYVALUE;
		COL--;
		if(COL==0)
			{
				ROW--;
				COL=0x04;	
				SCANCODE=SCANCODE<<1;				
				if(ROW==0) return 0xef;		
			}
		}
}
void DisplayScan(unsigned char displaydata[])
{
	unsigned char place;
	unsigned char i;
	for(place=0;place<8;place++)
	{
		PDISPLAY=((displaydata[place]<<4)&0xf0)|place;	
		for(i=200;i>0;i--);
	}
}