Input problems with PortD on Pic16F874A

[Petter]

Hi,
I have some serious problems, I need to use PortD.0 to PortD.3 for digital I/O.
It just wont work,!!!
I have read that:
“PortD is also the PARALLEL SLAVE PORT. To make it a general purpose I/O port, Bit4 of TRISE must be set to 0 IE TRISE.4 = 0”

So I tried:
TRISE.4=0

And to be on the safe side I also tried:
ADCON1 = 7
CMCON=7
TRISD = %11111111

And it still doesn’t work, does anyone have an idea?



/ Petter

[Bruce]

What are you trying to do that doesn't work? It's hard to tell with just
TRISD = %11111111.

[Petter]

Hi Bruce.
I am trying to use PortD.0 to PortD.3 as digital input.

“IF PortD.0 = 1 THEN…”
and it doesn’t work.


/ Petter

[Bruce]

IF PortD.0 = 1 THEN

Are you holding the pin at ground with a pull-down resistor until a button is
pressed taking the input high?

I don't have a 16F874A, but I do use the 16F876A with PORTD inputs, and
it works as expected.

It might help is you showed all your code & a schematic.

[Petter]

Hi again.

Yes, I am using pull-down resistor on all my inputs.
I will try to find some free time tomorrow to post my code & schematic.

/ Petter

[Petter]

Hi
This is my testcode & schematic:

'---------------------------------
Include "modedefs.bas"
@ DEVICE HS_OSC
DEFINE OSC 20
ADCON1 = 7
CMCON=7
TRISE.4=0
LED VAR PORTB.5

boot:
Pause 500
Low led
high porta.0

LOOP:
if portc.2 = 1 then high ut10
if portc.3 = 1 then high ut10
if portd.0 = 1 then high ut10
if portd.1 = 1 then high ut10

if portc.5 = 1 then high ut10
if portc.4 = 1 then high ut10
if portd.3 = 1 then high ut10
if portd.2 = 1 then high ut10

pause 1
low ut10
goto loop
'---------------------------------




link to my schematics:
http://www.mediespecialist.se/pic16f874a/874a.gif
and a picture:
http://www.mediespecialist.se/pic16f874a/IMG_2144.JPG

/ Petter