Hello all,

I connected a pair is 0.1uf caps across the 5V input to the digital cctry, and still it stalls.
What gets me is the fact that it stalls in the same place and the same outputs are sent high although they have not been set anywhere in my code.
My code is simple, it just sets 7 inputs high 1second after the other and then clears all 7 before restarting the loop.
I am driving 7 12V relays which in turn switch 7 110V pnumatic pistons.
The stall normally occurs after the first 2 pistons are energised, at this point 3 other outputs are set high. These outputs are not mentioned anywhere in my code.
The stall happends randomly, sometimes after 2 cycles and other times after many, many cycles but the same outputs are set!

Below, please find my code, although I doubt that this is the problem!

There is another board designed by someone else that uses a PIC and the same input and output cctry as I am using including the 0.1 uf caps, this board however is powered by a 12V power supply and not the 110V switchmode that I am using.
This board seems to work fine without any hitches.

Now I am really stressing, I cant seem to fix this!

Thank you for your time.


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HUND EQU 100
COUNT EQU -10000
count1 equ -10000


ORG 0
LJMP MAIN
;ORG 0003H
;LJMP EX0ISR
;ORG 0013H
; LJMP EX1ISR

MAIN: mov 8EH,#00010001B

MOV IE,#00000000B
MOV TMOD,#00010001H
MOV IP,#00000001B

MOV P0,#00011111B
MOV P1,#0H
MOV P2,#01111111B; for test
MOV P3,#00001100B


notch0: MOV P1,#00000000B
CALL DELAYLOOP

SETB P1.1
SETB P1.0
CALL DELAYLOOP


SETB P1.3
SETB P1.2
CALL DELAYLOOP


SETB P1.4
CALL DELAYLOOP


SETB P1.5
CALL DELAYLOOP


SETB P1.6
CALL DELAYLOOP


LJMP NOTCH0





;*****************************************


;******************************************************************
DELAYLOOP: MOV R7,#HUND
ENTER: MOV TH0,#HIGH COUNT
MOV TL0,#LOW COUNT
SETB TR0
DELAY: JNB TF0,DELAY
CLR TR0
CLR TF0
DJNZ R7,ENTER
RET
;******************************************************************