2016-01-29 09:42 PM
I got a NUCLEO-F446RE, which I use to send control signal to other board via SPI and GPIO. The NUCLEO and the board are powered separately. I wonder do I have to put them to the common ground so to make them work?
2016-01-29 09:53 PM
yes you are absolutely right. You will have make Ground common.
2016-01-30 10:07 AM
Or use Opto-Isolators if a common 0V would be a problem.