PIC24FJ64GA308 internal pullup reads 2V

guy · Joined: 21 Oct 2005 Posts: 297

Did anyone else notice this? Shouldn't it go up to VCC (3.3V) ?
I am testing with an oscilloscope which has 10M ohm resistor to GND so it's not because of the 'scope.
I noticed this on PORTE but didn't check other ports.

Ttelmah · Joined: 11 Mar 2010 Posts: 19496

No.....

They are not resistors. They are transistor current sources. Read the data sheet. Section 11.3;
"When the internal pull-up is selected, the pin pulls up to
VDD – 1.1V (typical). When the internal pull-down is
selected, the pin pulls down to VSS."
The pull up is also _weak_. 290uA typically. I'd have probably expected more like 2.1v, but your figure is not unreasonable.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

This is a Microchip question. Google for it. Example: