I've got a bit of a specific issue. For a project I've made a custom
Arduino Uno style PCB that sits on top of a Raspberry Pi. I can program the chip via SPI directly from the Raspberry Pi which turned out pretty neat. Also they can talk to each other using RX/TX.
Only it has a bit of a bad side-effect :-/ I want to turn the Raspberry Pi on and off via a relay (omron g5v-1) that's connected to the ATMega328.
This only seems to work if the SPI pins aren't connected to the Raspberry Pi's GPIO.
Also the Arduino's Reset pin which is attached to pin 15 on the GPIO seems to be triggered the moment the Raspberry Pi gets turned on.
With the current setting, if I read a button to flip the relay, it switches for a very short moment, and then is turned off again. With the SPI and reset pin unattached it works fine.
My guess is that I'd need some resistors to prevent this from happening (there's currently a 1k resistor to gnd on every SPI pin) would anyone be able to point me in the right direction on wether it needs to be pull-up/down and what type of value would make sense?
Best and great thanks,