4x4 matrix keypad with 16f690

[neillsun]

I am pulling my hair out with this one...

I have a 4x4 matrix ketpad connected to pins RC0 thru RC7 (RC0-RC3 are columns and RC4 thru RC7 are rows).

I have connected RC4-7 to ground through 10k resistors, and I am using the following code (PICCLite in MPLAB IDE) which I got from http://www.rs232pro.com/keypad_hardware.htm, I also copied the basic circuit, but I am relying on the internat OSC, so I haven't added the XTAL:

#include <pic.h>
#include "delay.h"

#define INPUT 1
#define OUTPUT 0

void main()
{

    const unsigned char keypad[]= {0x11,0x21,0x41,0x81,0x12,0x22,0x42,0x82,0x14,0x24,0x44,0x84,0x18,0x28,0x48,0x88};
    const unsigned char character[] = {'1','2','3','A','4','5','6','B','7','8','9','C','*','0','#','D'};
    unsigned char i,ii;

    TRISA3=OUTPUT;
    TRISC=0xFF;
    PORTC=0xF0;
  
    RA3=1;

    while(1)
    {
        PORTC=0x0F; /* init/re-init port */
        while(PORTC==0x0F); /* wait for key press */
        DelayUs(10);
        if(PORTC!=0x0F)
        {
            for(i=0;i<4;i++)
            {
                PORTC=1<<i;
                for(ii=0;ii<16;ii++)
                {
                    if(PORTC==keypad[ii])
                    { 
                        RA3=0; /* led */
                        DelayUs(200);
                        DelayUs(200);
                        RA3=1;
                        i=4;
                        break; 
                    }
                }
            } 
        }
    }
}

If I have it correct, the LED connected to RA3 should briefly switch off when a key is pressed, but nothing happens!!

Please can somebody point me in the correct direction??

Thanks.

 

[Mike K8LH]

You messed up the TRISC setting. Take a look at the original code again Sir...

 

[neillsun]

You messed up the TRISC setting. Take a look at the original code again Sir...

Thanks, Mike, although it still doesn't work! This one has me a bit stumped.

 

[pasicr]

Hi,
I think you have problem exactly here:

"but I am relying on the internat OSC, so I haven't added the XTAL"

simply add XTAL, the problem will be disappear,
regards

 

[snorazizul]

maybe u should play LED blinking with led at RA3 to conform that the chip can works without Xtal