Weak Pull-ups on 16F690

Hi,

Hope everyone is ok.

If I configure a pin as an input that will be connected to a n.o. switch and active when low, does it require an external pull-up resistor or can it just use the internal weak pull-up?

Thanks in advance for any help?

Angry Badger said:

Hi,

Hope everyone is ok.

If I configure a pin as an input that will be connected to a n.o. switch and active when low, does it require an external pull-up resistor or can it just use the internal weak pull-up?

Thanks in advance for any help?

Click to expand...

If you enable the weak pull-up resitors of the PIC16F690, you don't need external resistors. A nice feature of this PIC is that weak pull-ups are individually programmable.

Hi,

Thx eng1

Angry Badger said:

Hi,

Hope everyone is ok.

If I configure a pin as an input that will be connected to a n.o. switch and active when low, does it require an external pull-up resistor or can it just use the internal weak pull-up?

Thanks in advance for any help?

Click to expand...

You should be fine with that.

wow, am I slow.

As previously said the internal pullups usually work fine, in high noise environments they may not cut it though, just keep in mind that you're relying on them. If later down the line you have weird triggering events on lines relying on external pullups attach an extra lower value pullup, or decoupling capactior.

hi guys can u help me check my codes for the internal pull ups? i'm powering my 690 with the pickit2 while testing... when i'm using external 10k resistor the push button works without the pull ups..
thanks in advance~ ^^

#include <pic.h>
#define _XTAL_FREQ 4000000


void main (void)
{



RABPU = 1;
WPUA0 = 1;

TRISA = 0x07;
TRISC = 0x00;
ANSEL = 0x00;
ANSELH = 0x00;

while(1){

if(RA0 == 0){
__delay_ms(100);
PORTC = oxo1;
}
}
}