MEL PICBASIC Forum - Matrix Keypad routine

Here's a simple INCLUDE file wich allow to scan any matrix KeyPad format on any PORT you decide. Yeah i know, a bit code hungry but simple to use and it's free...

The defaults setings are

Keypad ROW are connected to PORTB<3:0>
Keypad COL are connected to PORTB<7:4>
Debounce delay = 200 mSec
No auto-repeat
Keypad type 4X4

Code example using the default setting

Code:

    INCLUDE "KeyPad.bas"         
    myvar                    var byte

start:
    @ READKEYPAD _myvar
    hserout ["Key=",dec myvar,13,10]
    goto start

NOT MUCH!
If you decide to change default settings, here's the DEFINEs list

Code:

        DEFINE KEYPAD_ROW        4        ' 4 ROW keypad       
        DEFINE KEYPAD_ROW_PORT   PORTB    ' ROW port = PORTB
        DEFINE KEYPAD_ROW_BIT    4        ' ROW0 = PORTB.4
        DEFINE KEYPAD_COL        4        ' 4 COL keypad
        DEFINE KEYPAD_COL_PORT   PORTB    ' COL port = PORTB
        DEFINE KEYPAD_COL_BIT    0        ' COL0 = PORTB.0
        DEFINE KEYPAD_DEBOUNCEMS 200      ' debounce delay = 200 mSec
        DEFINE KEYPAD_AUTOREPEAT 1        ' use auto-repeat feature
        DEFINE SCAN_ONCE         0        ; Read keypad untill a key is pressed

When using the auto-repeat feature, the delay is the debounce delay (DEBOUNCEMS)

Code example #2: Using a 8X4 keypad

Code:

    INCLUDE "KeyPad.bas"         

    '                      
    '    Hardware connection
    '    ===================
    DEFINE KEYPAD_ROW        8       ' 8 row 
    define KEYPAD_ROW_PORT   PORTB   '   on PORTB
    DEFINE KEYPAD_ROW_BIT    0       '      <7:0>
    DEFINE KEYPAD_COL        4       ' 4 col 
    DEFINE KEYPAD_COL_PORT   PORTA   '   on PORTA
    DEFINE KEYPAD_COL_BIT    0       '      <3:0>
    DEFINE KEYPAD_DEBOUNCEMS 200     ' debounce delay = 200 mSec
    define KEYPAD_AUTOREPEAT 1       ' use auto-repeat
    
    '
    '    Serial Communication definition
    '    ===============================
    DEFINE HSER_TXSTA 24h            ' enable transmit, BRGH=1
    DEFINE HSER_SPBRG 129            ' 9600 Bauds

    '   
    '    Variables definition 
    '    ===================
    myvar                    var byte

    '    ---------------------------------[Program Start]----------------------------------------------
start:
    @ READKEYPAD _myvar
    hserout ["Key=",dec myvar,13,10]
    goto start

It set the according TRIS register for you everytime you call the MACRO.. kinda bullet-proof

Everything is explain in the attach file... don't forget to rename it

Remapping keys:
Darrel gave this answer in the thread below for re-mapping keys on the keypad. This shows reversing key order, but any key order (or dis-order) will do using the lookup function.

Code:

@ READKEYPAD _myvar

; original keys   1  2  3  4  5  6  7 8 9 10 11 12 13  14 15 16 
LOOKUP  myvar,[0,16,15,14,13,12,11,10,9,8, 7, 6, 5, 4, 3, 2,  1],myvar

If they don't line up right, you can change the LOOKUP to a pattern that matches.

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