device = 16f628a

CONFIG INTRC_OSC_NOCLKOUT, CP_OFF, WDT_OFF, PWRTE_ON, LVP_OFF
Delayms 200                        ; stabilize
all_digital = true
PORTB_PULLUPS = TRUE

dim temp as byte
dim keypad as byte
symbol beep = porta.6
symbol par_int = porta.7          ; parallel interrupt output
symbol ser_int = porta.1
symbol switch = porta.4          ; microswitch input
symbol rs232out = porta.0        ; serial output

trisa=%00010000
porta=255

loop:

repeat                          ; wait until a key is pressed
    temp = inkey
until temp<>16
keypad = lookup temp, [138,128,139,255,135,136,137,255,132,133,134,255,129,130,131]  ;conversion to 'true' bin-values

if switch = 0 then              ; read jumper setting
    porta = keypad              ; send true-value to portA
    pulsout par_int, 100, low       ; interrupt pulse 1 ms.
else
    keypad = keypad - 128
    pulsout ser_int, 100, low       ; interrupt pulse 1 ms.
    serout rs232out, 16486, [ keypad ]   ; send data serial to portA.0. 8 bits, 9600 baud, no parity
end if

sound beep, [115,9]             ; short beep at every keypress + debounce

repeat                          ; wait until key is released
    temp=inkey
until temp = 16
porta = 255                     ; send initial value to portA

goto loop