| Note: Remember that the ATmega runs on 5V, and therefore it reads 5V as logical high.
I use a classic NFC reader PNR532 V3 (like: https://images.app.goo.gl/uouKyD4WnnLDmuhHA) - SPI connection.
I used a lots of that reader connected directly on 5V of the omega PINOUT (expansion header) with ARDUINO DOCK 2 with onion board.
Now I bought 100 new NFC reader and if I connect them on an ARDUINO UNO everything work very good, but if I use the Onion Power on the ARDUINO DOCK 2 (5V) they don't work fine.
I noticed two thing:
- with the 3,3V of the expansion header the new readers works good
- these new reader are more powerfull, the reading range is wider.
Is the 5V power of the ARDUINO DOCK different from the real Arduino UNO?
many many thanks!!!