keypad decode.c

4x4矩阵扫描键盘 用于PIC16f8

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~//
//~ To test PIC16F877 io ports A,B,C,D,E; using RE2 as switch.  ~//
//~    Created by Henry Tan for EE2001. All rights reserved.    ~//
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~//


#include "io16f877.h" // The hardware register definition file

// Define the pins to use
#define Kpad1 RB0
#define Kpad2 RB1
#define Kpad3 RB2
#define Kpad4 RB3 

//Global variables declare for the interrupt service routine
int value = 0x8000;
volatile int inst_count = 0, inst_code = 0, test_value = 0;
volatile unsigned char out0 = 0, out1 = 0, out2 = 0, out3 = 0;
volatile char key;


//Functions prototype
void delayUs(int count);
void portIO(void);
char Keypad_decode(void);

// Initialize all port I/O configuration and enable all the needed interrupt signal
void portIO(void)
{
	TRISB = 0x8F;  					// set port B pin 7 as input, others as output 
	TRISC = 0x00;  					// set port C as output 
	PORTC = 0x00;  					// clear port C
    GIE   = 1;   				    // global interrupt enabled
	PEIE  = 1;     					// peripheral interrupt enabled
	RBIE  = 1;     					// port B interrupt enabled
	RBIF  = 0;     					// clear port B interrupt flag
}

//This function is called to cause a delay of count Us.
void delayUs(int count)
{
	int i, j;
	for (i=0; i<count; i++)
	{
		for (j=0; j<5; j++);
	}
}

char Keypad_decode(void)
{
	int key_value = 0;
	key_value = Kpad4*8 + Kpad3*4 + Kpad2*2 + Kpad1;
	switch (key_value)
	{
		case 0:
			return '1';
		case 1:
			return '2';
		case 2:
			return '3';
		case 3:
			return 'A';
		case 4:
			return '4';
		case 5:
			return '5';
		case 6:
			return '6';
		case 7:
			return 'B';
		case 8:
			return '7';
		case 9:
			return '8';
		case 10:
			return '9';
		case 11:
			return 'C';
		case 12:
			return '*';
		case 13:
			return '0';
		case 14:
			return '#';
		default:
			return 'D';
	}
	
}

#pragma vector=0x04
__interrupt void isr(void)
{
	if (RBIF == 1)   						// if pushbutton is pressed
	{
	    RBIF = 0;
		
		key = Keypad_decode();
		
		switch (key)
		{
			case '1':		
				out0 = 1;
				out1 = 0;
				out2 = 0;
				out3 = 0;
				break;
			case '2':		
				out0 = 0;
				out1 = 1;
				out2 = 0;
				out3 = 0;
				break;
			case '3':		
				out0 = 1;
				out1 = 1;
				out2 = 0;
				out3 = 0;
				break;
			case '4':		
				out0 = 0;
				out1 = 0;
				out2 = 1;
				out3 = 0;
				break;	
			case '5':		
				out0 = 1;
				out1 = 0;
				out2 = 1;
				out3 = 0;
				break;
			case '6':		
				out0 = 0;
				out1 = 1;
				out2 = 1;
				out3 = 0;
				break;
			case '7':		
				out0 = 1;
				out1 = 1;
				out2 = 1;
				out3 = 0;
				break;
			case '8':		
				out0 = 0;
				out1 = 0;
				out2 = 0;
				out3 = 1;
				break;
			case '9':		
				out0 = 1;
				out1 = 0;
				out2 = 0;
				out3 = 1;
				break;
			case '0':		
				out0 = 0;
				out1 = 0;
				out2 = 0;
				out3 = 0;
				break;
			default:		
				out0 = 1;
				out1 = 1;
				out2 = 1;
				out3 = 1;
		}	
	}		r
	
}


void main (void)
{
	portIO();
	
	while (1)
	{ 
		RC0 = out0;
		RC1 = out1;
		RC2 = out2;
		RC3 = out3;
	    		
	}//endWhile
}//endMain