tazntex
- 19th February 2010, 15:22
Hello,
Looking at the keypad example from Bruce's website, is there anyway this can be modified to show if two keys are pressed at the same time? For example, if I pressed two keys at the same time I could turn right and go forward.
getkey:
PAUSE 50 'Debounce key-input
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 keys down, loop
PAUSE 50 ' Debounce key-input
getkeyp:' Wait for keypress
FOR row = 0 TO 3 ' 4 rows in keypad
PORTB = 0 ' All output-pins low
TRISB = (DCD row) ^ $ff ' Set one row pin to output
col = PORTB >> 4 ' Read columns
IF col != $f THEN gotkey' If any keydown, exit
NEXT row
GOTO getkeyp ' No keys down, go look again
gotkey: ' Change row and column to key number 1 - 16
key = (row * 4) + (NCD (col ^ $f))
'NOTE: for 12-key keypad, change to key = (row * 3)
RETURN ' Subroutine over
Thanks
Looking at the keypad example from Bruce's website, is there anyway this can be modified to show if two keys are pressed at the same time? For example, if I pressed two keys at the same time I could turn right and go forward.
getkey:
PAUSE 50 'Debounce key-input
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 keys down, loop
PAUSE 50 ' Debounce key-input
getkeyp:' Wait for keypress
FOR row = 0 TO 3 ' 4 rows in keypad
PORTB = 0 ' All output-pins low
TRISB = (DCD row) ^ $ff ' Set one row pin to output
col = PORTB >> 4 ' Read columns
IF col != $f THEN gotkey' If any keydown, exit
NEXT row
GOTO getkeyp ' No keys down, go look again
gotkey: ' Change row and column to key number 1 - 16
key = (row * 4) + (NCD (col ^ $f))
'NOTE: for 12-key keypad, change to key = (row * 3)
RETURN ' Subroutine over
Thanks