PULL-UP RESISTORS ON OUTPUT PINS

[neko efecktz]

Good morning Everybody.
I have resolved my previous question posted yesterday.

Just a few quick questions.

What effect would it have, if any, if the output pins of a PIC  namely  PIC16F877A had 10K pull-up resistors.
I just built a new board using different ports to my previous one, to make better use of port C particularly I want to use the I2C option of port C.
Port C has terminals for I2C.
 
I made provision on Ports B & C for pull-up resistor arrays and without thinking fitted an array to each.
I was planning on using Port A is analog input, already set up and working, Port B as Input, Port C for Output including I2C, Port D is set up for the 1602 LCD and Port E is not committed.


Is there any advantages in using Port B or Port C as input or output? which way would you go?  Please keep it clean.
I could suck out the array on Port C.

Thank you
BILL.

[Fire Doger]

It doesn't have any effect that will make a difference at this level.
Although usually development board doesn't have soldered pull resistors (or they have dip switch to enable them).
You can just populate a female socket instead of the resistor array to be able to remove them on the fly.

Don't think each port as an input or output, every time you will define what they will be depending on your needs (peripherals that you gonna use, etc.)

[danadak]

The 10K will add to power dissipation, a consideration if power is
battery derived.

If the pin is tri stated on power up then of course the pullup
forces a logic 1 at the pin, another consideration for external
logic driven by pin. That's a consideration if your pin drives a
switched high power load that should not be on when first
starting up until processor gains control over system.


Regards, Dana.