I have an Moteino board (similar to Arduino with a radio module). The Moteino uses the radio module to collect weather data from my Davis weather station. I want to use I2C to send this data to an RPi which then uploads it to Weather Underground.
Searching the internet, it seems that when RPi and Arduino are communicating via I2C, the RPi is the normally the master. But I did see there is a PIGPIO library that lets the RPi be the slave.
Because there's a lot going on when the Moteino is using the radio module, I'm worried that if the RPi was the master, the I2C interrupts might cause some problems. So I'm leaning towards making the RPi the slave. Alternatively, I could make the RPi the master and use a GPIO pin from the Arduino that would signal the RPi that the radio isn't being used and now is a good time to request data from the Moteino.
I don't really know the pros and cons of using the RPi as a slave, so I'm looking for suggestions on which way to proceed. BTW - Moteino is 3.3 volts, so I don't have to worry about sending 5V to the RPi like with many Arduino boards.