flexible 4x4 keypad driver

[krantz]

Hi to all!
Anyone used this driver within isr ( in my case INT_RB).
I can input only keys on first column (col0).
Any help?
Thanks

Krantz

[treitmey]

Does it display results, but the wrong letter. OR nothing at all?

[krantz]

Hi!
here the code in which during main, I to focus on keyboard input, it do a simple task.
The driver see only key press on first column of the matrix (col0) inputting however the right charachters ( I have '1' , '4' , '7' , 'A').

If I insert the call to kbd_getc(); directly in main ( as in the original example) without use of interrupt (int_rb) the driver work fine inputting all chars.

Many thanks!





#include "C:\Temp\TurboC\Mplab\16f877.h"




//Keypad connection:
#define row0 PIN_B4
#define row1 PIN_B5
#define row2 PIN_B6
#define row3 PIN_B7
#define col0 PIN_B0
#define col1 PIN_B1
#define col2 PIN_B2
#define col3 PIN_B3



char const KEYS[4][4] =
{{'1','2','3','F'},
{'4','5','6','E'},
{'7','8','9','D'},
{'A','0','B','C'}};


#define KBD_DEBOUNCE_FACTOR 33 // Set this number to apx n/333 where
// n is the number of times you expect
// to call kbd_getc each second

void kbd_init()
{
//set_tris_b(0xF0);
//output_b(0xF0);
port_b_pullups(true);
}


short int ALL_ROWS (void)
{
if(input (row0) & input (row1) & input (row2) & input (row3))
return (0);
else
return (1);
}


char kbd_getc()
{
static byte kbd_call_count;
static short int kbd_down;
static char last_key;
static byte col;

byte kchar;
byte row;

kchar='\0';



if(++kbd_call_count>KBD_DEBOUNCE_FACTOR)
{
switch (col)
{
case 0:
output_low(col0);
output_high(col1);
output_high(col2);
output_high(col3);
break;

case 1:
output_high(col0);
output_low(col1);
output_high(col2);
output_high(col3);
break;

case 2:
output_high(col0);
output_high(col1);
output_low(col2);
output_high(col3);
break;

case 3:
output_high(col0);
output_high(col1);
output_high(col2);
output_low(col3);
break;
}

if(kbd_down)
{
if(!ALL_ROWS())
{
kbd_down=false;
kchar=last_key;
last_key='\0';
}
}
else
{
if(ALL_ROWS())
{
if(!input (row0))
row=0;
else if(!input (row1))
row=1;
else if(!input (row2))
row=2;
else if(!input (row3))
row=3;

last_key =KEYS[row][col];
kbd_down = true;
}
else
{
++col;
if(col==4)
col=0;
}
}
kbd_call_count=0;
}

return(kchar);
}




//===========================
void main()
{
enable_interrupts(GLOBAL);

enable_interrupts(INT_RB);



kbd_init();

printf("\r\Starting ...");

while(TRUE)
{



output_high(PIN_d0);
delay_ms(300);
output_low(PIN_d0);
delay_ms(300);
}

}




#int_rb

int_rb_isr()


{

char k;

k=kbd_getc();
if(k!=0)
{
if(k=='*')
printf("%c", '*');
else
printf("%c", k);
}

}

[treitmey]

If it works by itself but not with the IRQ, then that would seem to be the problem.

Your int_Rb works by seeing a change on the upper nibble of port b. B4-B7...the rows
so in normal operation:
1. upper bits of port b are pulled up. These are the rows.
2. column are outputted as 0.
3. you press a key that will connect a row to column. That pulls a single row line to ground(0). That row(B4-B7) is seen by the IRQ. Then you can read/decode it.

I see you have two lines commented out in kpd_init.

Are you seeing any place in the code that doesn't look correct.

[krantz]

Hi treitmey,
sorry for delay, but week end....!

The lines in keyb_init are commented in the original version of the driver and I got it as was, but after some tests it seems they shall be set in that mode to do work the driver .

To check for irq involvement on the problem, I've removed the int_rb and inserted the call to kbd_getc directly in main as shown.

In this test the driver doesn't capture any key press not even the keys on col0.

The only way I found to do work the driver is to remove also the on-off delay on
pin D0 as shown, and then the driver capture properly all the key presses .

I don't understand well how the driver works but it seems that it needs several passes to reach the condition (kbd_call_count>KBD_DEBOUNCE_FACTOR) and then decode the key.

Pheraps during the irq it doesn't has this chance, but I don't understand in the case of the on-off on pin D0 what could be the bug (perhaps the key press time width is less than 300+300 ms delay inserted !) .

Thanks again for support,

Krantz




#include "C:\Temp\TurboC\Mplab\16f877.h"




//Keypad connection:
#define row0 PIN_B4
#define row1 PIN_B5
#define row2 PIN_B6
#define row3 PIN_B7
#define col0 PIN_B0
#define col1 PIN_B1
#define col2 PIN_B2
#define col3 PIN_B3



char const KEYS[4][4] =
{{'1','2','3','F'},
{'4','5','6','E'},
{'7','8','9','D'},
{'A','0','B','C'}};


#define KBD_DEBOUNCE_FACTOR 33 // Set this number to apx n/333 where
// n is the number of times you expect
// to call kbd_getc each second

void kbd_init()
{
//set_tris_b(0xF0);
//output_b(0xF0);
port_b_pullups(true);
}


short int ALL_ROWS (void)
{
if(input (row0) & input (row1) & input (row2) & input (row3))
return (0);
else
return (1);
}


char kbd_getc()
{
static byte kbd_call_count;
static short int kbd_down;
static char last_key;
static byte col;

byte kchar;
byte row;

kchar='\0';



if(++kbd_call_count>KBD_DEBOUNCE_FACTOR)
{
switch (col)
{
case 0:
output_low(col0);
output_high(col1);
output_high(col2);
output_high(col3);
break;

case 1:
output_high(col0);
output_low(col1);
output_high(col2);
output_high(col3);
break;

case 2:
output_high(col0);
output_high(col1);
output_low(col2);
output_high(col3);
break;

case 3:
output_high(col0);
output_high(col1);
output_high(col2);
output_low(col3);
break;
}

if(kbd_down)
{
if(!ALL_ROWS())
{
kbd_down=false;
kchar=last_key;
last_key='\0';
}
}
else
{
if(ALL_ROWS())
{
if(!input (row0))
row=0;
else if(!input (row1))
row=1;
else if(!input (row2))
row=2;
else if(!input (row3))
row=3;

last_key =KEYS[row][col];
kbd_down = true;
}
else
{
++col;
if(col==4)
col=0;
}
}
kbd_call_count=0;
}

return(kchar);
}




//===========================
void main()
{



kbd_init();

printf("\r\Starting ...");

while(TRUE)
{

char k;

k=kbd_getc();
if(k!=0)
{
if(k=='*')
printf("%c", '*');
else
printf("%c", k);


//output_high(PIN_d0);
//delay_ms(300);
//output_low(PIN_d0);
//delay_ms(300);
}

}

}