It's open drain - you'll need a pullup resistor.

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Gary Neal
Sent: Wednesday, August 22, 2001 12:01 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: [PIC]: PORTA.4 on p16f8870 ON/OFF?


Hi,

         I wrote some simple code to turn on (high) all the lines of the
16f870.  Just wanted to see if they all worked and could light up an
LED.  They all come on except PORTA.4.  I can't get it to go high at
all.  Tried three different PICs, so it's not just that specific
PIC.  Here's the code:

--------------------------------------------------


x               var     word            'Loop counter
TRISA=0
TRISB=0
TRISC=0

PORTA = 0
PORTB = 0
PORTC = 0

Main:
for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTA = %00000001

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTA = %00000011

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTA = %00000111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTA = %00001111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTA = %00011111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTA = %00111111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTB = %00000001

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTB = %00000011

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTB = %00000111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTB = %00001111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTB = %00011111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTB = %00111111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTB = %01111111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTB = %11111111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTC = %00000001

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTC = %00000011

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTC = %00000111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTC = %00001111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTC = %00011111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTC = %00111111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTC = %01111111

for x = 0 to 88                                 '1 second loop
        pause 10
next x
PORTC = %11111111

for x = 0 to 88                                 '1 second loop
        pause 10
next x

PORTA = 0
PORTB = 0
PORTC = 0

goto Main

---------------------------------------


Anyone have a clue what's wrong?

Thanks,

Gary




"Imagination is more important than knowledge."
                                 A. Einstein

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http://www.piclist.com hint: The PICList is archived three different
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