Hi Dan,
I googled to see what other values are quoted for the pull-up. The input impedance is claimed to be 100 megohms. The pull-ups, when activated, are 20k ohms to 50k ohms according to the Arduino site. I pulled my approximately 30k value from a ATmega328P?chip data sheet.
You could try adding your own 20k pull-up. That would be easier than replacing the Nano. It is possible the processor chip on the nano is not in spec. I'm wondering if the cheap Nano board makers have found a source of reject?ATmega328P chips to keep costs down? Very unlikely, but wondering.?
The pins should reset to the correct configuration via the firmware every time the power is re-applied.?
Interestingly, I'm noticing a number of people saying their encoders are not working, that also relies in the internal pull-ups. I started to go through the encoder not working threads to see if they were all solved by replacing the encoder or if other solutions were used. But, this is what is making me wonder if there are Nano boards with processor chips with out of spec pull-ups.
Tom, wb6b
