Hi,

I need to build a test equipment for a later project. I need a three phase
square wave generator running at 50 Hz. No problem with that.
I wrote the code simulated it in MPLAB 3.22.02 (MPSIM 6.20.01) works fine.
Programmed a JW part and got the signals alright EXCEPT the GP2 which is
allways zero. I broke down the code to a minimum, just as a try to isolate
the problem. I programmed an other JW part and even wasted an OTP, all with
the same result.
AFAIK the GP2 is bidirectional, so why can I make this working ?

;3phase Ver. 1.00
;       Pin     Port    Func.   Comment
;       1               VDD     +5VDC
;       2       GP5 I   FQ      Input 50/60 Hz
;                               0=50 Hz / 1=60 Hz
;       3       GP4 O   --      N/A OUTPUT
;       4       GP3 I   --      N/A Connect to +5
;       5       GP2 O   Wout
;       6       GP1 O   Vout
;       7       GP0 O   Uout
;       8               VSS     0V

        LIST P=12C509, R=DEC
        INCLUDE "p12C509.inc"
        __FUSES _MCLRE_OFF & _CP_OFF & _WDT_OFF & _IntRC_OSC

; PORT GPIO             Bit
Wout            equ     2
Vout            equ     1
Uout            equ     0
FQ              equ     5

;RAM
waitcnt_H       equ     0x08    ;
waitcnt_L       equ     0x09    ;
;******************************************************************
        ORG     0x000
init
        movwf   OSCCAL          ; Calibrate !

;                 76543210
        movlw   b'11101000'     ; select input pins (1=IN)
        tris    GPIO            ; make pins input
;******************************************************************
;Test code
loop
         bcf    GPIO, Uout      ; 0
         bcf    GPIO, Vout      ; 0
         bcf    GPIO, Wout      ; 0

         bsf    GPIO, Uout      ; 1
         bsf    GPIO, Vout      ; 1
         bsf    GPIO, Wout      ; 1

        goto    loop
;******************************************************************
        ORG     0x3ff
;       movlw   0x80            ; Remove if OTP
;******************************************************************
        END


Best regards

Bjarne Nebelong
nebelong@algonet.se