Hi all

I have started playing with my first Teensy and facing an issue hope someone can help.

I am following the "Laptop Keyboard conversion to USB" guide from Frank https://www.hackster.io/frank-adams/...-to-usb-0771f1

The first thing I have tried is to just load Franks Keyboard scanner code into the Teensy and run it. given at https://github.com/thedalles77/USB_L...ecoder_3p2.ino

I ran it with the keyboard attached and it stopped because the code detected some pins are shorted on the keyboard . As I couldn't find any shorts on the KB, I run the code without the keyboard attached and it still detected the short between those pins.

The way it is working is that it turns pullups on all pins, Then takes one pin at a time to output 0 (i,e shorted to ground) and then reads back all the other pins to see if any other pins has gone to 0 as well. If so this means a short between those pins.

I am confused how it is finding non existent shorts. I looked at the pin voltage that was supposedly shorted with my scope and it stays high throughout the scan of the other pin.

Any help will be most appreciated.