open drain output as digital output?

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- 8th November 2006, 05:15
droptail

open drain output as digital output?

Will a port pin that is an "open drain output" support a SEROUT command?
The pin in question RA4 is multiplexed with a Timer0 module clock input. Can it still be used as a digital pin?

Will a SEROUT command set the pin digital output even if the pin was previously set as analog input?
- 8th November 2006, 05:52
Jerson

Sure this does not apply generally to all Pics. Can you specify the device you talk about?

Jerson
- 8th November 2006, 07:03
droptail

Microchip PIC16C716
- 8th November 2006, 20:37
Dave

droptail, just use a pullup resistor of about 2.7k to 4.7k.

Dave Purola,
N8NTA
- 9th November 2006, 03:34
mister_e

Quote:

Will a port pin that is an "open drain output" support a SEROUT command?

Yes for sure, use Dave's suggestion.

Quote:

The pin in question RA4 is multiplexed with a Timer0 module clock input. Can it still be used as a digital pin?

Yes

Quote:

Will a SEROUT command set the pin digital output even if the pin was previously set as analog input?

Nope, this is also why we see many question about that. Always make sure you disable multiplexed stuff(when possible) on an i/o before using it.

ADCs/analog comparator are popular.
- 9th November 2006, 17:33
droptail

I have success with 1k hold up for now.
I also have no problems for years with SEROUT command working on a port pin set as analog and input, why?

TRISA =255 'all PortA Inputs
ADCON1 =0 'all PortA Analog

SerOut PORTA.0,N2400 ...
- 10th November 2006, 01:37
droptail

Thank you both for your help.
- 10th November 2006, 03:11
mister_e

Probably at slow baudrate it may work... but i will never trust or use that.