Hi, thanks for the reply.
I did changed the config and enabled the WDT. The code looks like this now:
Code:
DEFINE OSC 4
Define OSCCAL_1K 1
@ __CONFIG _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_ON & _MCLRE_OFF & _CP_ALL
'// For PIC12C671
include "modedefs.bas"

'// Define variables
ToTx VAR GPIO.0
PAUSE 30 
'// OSCCAL=0
TRISIO = %111110 
OPTION_REG = %10001000
ToTx = 0 
INTCON=0 
ADCON0.0=0
ADCON1=7

send:
if gpio.1=0 then
serout ToTx,N2400,["G0"]
Low ToTx
pause 10
endif

if gpio.2=0 then
serout ToTx,N2400,["G1"]
Low ToTx
pause 10
endif

if gpio.3=0 then
serout ToTx,N2400,["G3"]
Low ToTx
pause 10
endif

if gpio.4=0 then
serout ToTx,N2400,["G4"]
Low ToTx
pause 10
endif

goto send
end
My circuit only gets power when any button is pressed. I can try to scan the paper after drawing the circuit or try to find a software over the net if you think the circuit could be the culprit.
But I would like to add that rest all the buttons are working fine, so I believe the circuit is ok, GP3 is connected the same way as all other pins. Even the voltage on that pin behaves the same way as on any other pin under same circumstances but no DATA OUTPUT is there.