Matrix keyboard for up to 32 keys
Hello
For scan a keyboard with up to 16 keys we use this code from Melabs,
I need it for up to 32 keys. It is possible with this construct, and how?
Thanks
Regards
Pedro
Code:
' PicBasic Pro program to display key number on LCD
' Define LOADER_USED to allow use of the boot loader.
' This will not affect normal program operation.
Define LOADER_USED 1
' Define LCD connections
Define LCD_DREG PORTD
Define LCD_DBIT 4
Define LCD_RSREG PORTE
Define LCD_RSBIT 0
Define LCD_EREG PORTE
Define LCD_EBIT 1
' Define program variables
col var byte ' Keypad column
row var byte ' Keypad row
key var byte ' Key value
OPTION_REG.7 = 0 ' Enable PORTB pullups
ADCON1 = 7 ' Make PORTA and PORTE digital
Low PORTE.2 ' LCD R/W low (write)
Pause 100 ' Wait for LCD to start
Lcdout $fe, 1, "Press any key" ' Display sign on message
loop: Gosub getkey ' Get a key from the keypad
Lcdout $fe, 1, #key ' Display ASCII key number
Goto loop ' Do it forever
' Subroutine to get a key from keypad
getkey:
Pause 50 ' Debounce
getkeyu:
' Wait for all keys up
PORTB = 0 ' All output pins low
TRISB = $f0 ' Bottom 4 pins out, top 4 pins in
If ((PORTB >> 4) != $f) Then getkeyu ' If any keys down, loop
Pause 50 ' Debounce
getkeyp:
' Wait for keypress
For col = 0 to 3 ' 4 columns in keypad
PORTB = 0 ' All output pins low
TRISB = (dcd col) ^ $ff ' Set one column pin to output
row = PORTB >> 4 ' Read row
If row != $f Then gotkey ' If any keydown, exit
Next col
Goto getkeyp ' No keys down, go look again
gotkey: ' Change row and column to key number 1 - 16
key = (col * 4) + (ncd (row ^ $f))
Return ' Subroutine over
End
