Can I wire a pin from the gpio of a raspberry pi to a pin of a sparkfun pro micro (Arduino micro)? If so how?
1) Would I need to connect the ground from the pi to the pro micro?
2) Does it matter which micro I get, the 3.3v or 5v, since I'm only communicating in one way (pi to micro)? I only need to communicate in on/offs.
3) If this type of gpio to gpio is possible would it be faster or slower than something more complex like i2c?
Btw: the plan is to get the micro to send key (HID) commands to a connected computer when the pi receives some input. I only need to send about 5 distinct keys, so I was planning on just using the gpio to gpio wiring. Feel fee to let me know if that's a wrong headed approach. I know very little about any of this.