Why isn't port D working on PIC16F877

[MOLLY]

Hello, im just doing an easy test with
Output_high(PIN_D0) and so on. But port D is not responding. No change in voltage level!
What have I missed?

Thanks for any reply

Michael
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This message was ported from CCS's old forum
Original Post ID: 144514566

[Dave Yeatman]

How are you setting up the Port pins. Can you show us the initialization section of the program?? If it is short then post the whole thing otherwise we would be just wildly guessing,.... :-)

:=Hello, im just doing an easy test with
:=Output_high(PIN_D0) and so on. But port D is not responding. No change in voltage level!
:=What have I missed?
:=
:=Thanks for any reply
:=
:=Michael
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This message was ported from CCS's old forum
Original Post ID: 144514567

[MOLLY]

I'm not setting up any ports, just using output_high(PIN_D0) and output_low(PIN_D0), this works just fine with all other ports, it's just port D that is not responding

Thank you again!
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This message was ported from CCS's old forum
Original Post ID: 144514569

[allen_m]

Hi Molly,

Check how you are setting PortE TRISE register ... if you inadvertantly set bit 4 of the TRISE register, Port D goes into PSP mode and will not respond to output_Hi/lo() calls.

Also try external pullups on Port D (perhaps not strictly required).

Allen M.
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This message was ported from CCS's old forum
Original Post ID: 144514643

[Bjorn Peschl]

:=Hello, im just doing an easy test with
:=Output_high(PIN_D0) and so on. But port D is not responding. No change in voltage level!
:=What have I missed?
:=
:=Thanks for any reply
:=
:=Michael


Are you sure that it isn´t a hardware problem?
If you have include the "standard 16F877.h" file, the following program should work...

# include "16F877.h"
# use delay (clock=4000000)

int i =0;

main ()

{

Loop:

for (i=1;i<=5;++i)

{
output_high( PIN_D0 );
delay_ms( 100 );
output_low( PIN_D0 );
delay_ms( 100 );
}

for (i=1;i<=5;++i)
{
output_high( PIN_D1 );
delay_ms( 100 );
output_low( PIN_D1 );
delay_ms( 100 );
}

Goto Loop;
}
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This message was ported from CCS's old forum
Original Post ID: 144514672

[John Taylor]

Be sure this is included in the code:

setup_psp(PSP_DISABLED);

This will ensure that the PSP (Port D) in in I/O mode, not PSP.

Also, if you are using fast I/O, the port will be all inputs.

jt

:=I'm not setting up any ports, just using output_high(PIN_D0) and output_low(PIN_D0), this works just fine with all other ports, it's just port D that is not responding
:=
:=Thank you again!
___________________________
This message was ported from CCS's old forum
Original Post ID: 144514725