I can't get my inputs to work. I am using a pull up switch, have set all pi=
ns but 1 to outputs, then tied them to ground. I am using a PIC16F628 with =
the configs set to everything off/disabled except the power up timer. I hav=
e selected the internal oscillator. I'm a programmer..not EE, so that's my =
weak point but i have been checking the circuit for 3 days and can't find w=
hat's wrong. The chip works because i got one of those LED blinking things =
to work fine. Guys...thank you so much...it's very upsetting when you're ju=
st starting out and can't get the easiest thing to work. The only odd thing=
 i could find was that my programming software (WinPicProg, from Dontronics=
) generates a different config word then does MPLAB with the same settings.=


Here is my code:

TMR0            EQU             1
OPTION_R        EQU             1
PORTA           EQU             5
PORTB           EQU             6
TRISA           EQU             5
TRISB           EQU             6
STATUS          EQU             3
ZEROBIT         EQU             2
CARRY           EQU             0
PCON            EQU             0EH
COUNT           EQU             20H

                        LIST P=3D16F628                                                 ;  tells which processor is use
;MPLAB generated        __CONFIG 0x3F10
                        __CONFIG 0x3D10  ;WinPicProg generated
                =09
                        org             0
                        goto    START

; config section

START                   bsf     STATUS, 5
                        movlw   b'11111111'
                        movwf   TRISA
                        movlw   b'00000000'
                        movwf   TRISB

                        movlw   b'00000100'
                        movwf   OPTION_R
                        clrf    PCON

                        bcf     STATUS, 5
                        clrf    PORTA
                        clrf    PORTB

; program starts now

BEGIN           btfsc   PORTA, 1
                        goto    BEGIN
                        movlw   b'11111111'
                        movwf   PORTB
KEEPON          btfss   PORTA, 1
                        goto    KEEPON
                        clrf    PORTB
                        goto    BEGIN   =09

                        END

Here is my circuit:
                                   GND
                                    |
[9V+ Battery]--[914 diode]--[7805 Volt Reg]--+
                                             |
                          +-----[10k Res]----+
                          |                  |
            A1/PIN 18-----+--[switch]--GND   |
                                             |
           Vdd/PIN 14------------------------+

           Vss/PIN 05------------------------GND

            B4/PIN 10--[470 Ohm Res]--[LED]--GND
=20
            B3/PIN 09--[470 Ohm Res]--[LED]--GND

All other pins set as output, tied to ground. The switch part of the circui=
t allows 4.5V to A1 and when pressed drops the voltage down to 0. I checked=
 with my multimeter. Thank you so much everyone.

E-Mail: rrc124@pitt.edu

Robert Campbell
                     =20

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