PIC16F88, PORTA strange behaviour

From: Frank Bemelman (f.bemelmanx_at_xs4all.invalid.nl)
Date: 12/02/04 

Date: Thu, 2 Dec 2004 14:17:10 +0100

Strange problem:

Setting an output low on PORTA, causes another output
on PORTA to go low too.

Below is the entire program. It should generate two signals:

---, ,---, ,---, ,---, ,---
   '---' '---' '---' '---'
-, ,---, ,---, ,---, ,---
 '- -' '---' '---' '---'

But instead gives this:

-, ,-, ,-, ,-, ,-
 '-----' '-----' '-----' '-----'
-, ,---, ,---, ,---, ,---
 '- -' '---' '---' '---'

If I generate the second signal on an output of PORTB,
it all works okay.

L0000: MOVLW 00
L0001: MOVWF 0A
L0002: GOTO 004
L0003: NOP
L0004: CLRF 04
L0005: MOVLW 1F
L0006: ANDWF 03,F
L0007: BSF 03,5
L0008: BCF 1F,4
L0009: BCF 1F,5
L000A: MOVF 1B,W
L000B: ANDLW 80
L000C: IORLW 0F
L000D: MOVWF 1B
L000E: MOVLW 07
L000F: BCF 03,5
L0010: MOVWF 1F
L0011: MOVLW 00
L0012: TRIS 5
L0013: NOP
L0014: NOP
L0015: NOP
L0016: BSF 05,2
L0017: NOP
L0018: NOP
L0019: NOP
L001A: BCF 05,3
L001B: NOP
L001C: NOP
L001D: NOP
L001E: BCF 05,2
L001F: NOP
L0020: NOP
L0021: NOP
L0022: BSF 05,3
L0023: GOTO 013
END

Any suggestions? 

-- 
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

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