"William K. Borsum" wrote:
> Hi you Atmel types:
> Have an application we have to convert to a PIC in the very near future,
> and am trying to figure out how the circuit we have been given is working.
> Two Questions:
> Port 3, Pin 6, setup for input--does it have an internal pull up resistor,
> and if so, what is the value (approximately)?
> Port #, Pin 7, setup for output--is this an open collector/drain type
> driver? Pin has a pull up to 3.0 volts for level shifting from the 4.5V
> rail--and this is the only way I can figure that it would work.

Port 3 pin 6 doesn't exist physically, it is the internal digital output
of the analog comparator doubled by port 1 pins 0 and 1 (AIN1 and AIN0)
when programmed to it.  P36 can be read as a normal port pin, but it is
the result of the comparator only. Pins P10 e P11 does NOT have a
practical pull up.

Port 1 or 3, pin 7, is a drain "open collector" type, with a small pull
up. They can drain 20mA easily when programmed for output low level.

I don't know if I understood exactly what you asked about pin 7.

--------------------------------------------------------
Wagner Lipnharski - UST Research Inc. - Orlando, Florida
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