Testing Raspberry Pi I2C bus with Arduino
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README.md
i2cmaster.py
i2cmaster_loop.py
i2cslave.ino

README.md

rpi_i2c_test

Testing I2C connections between Raspberry Pi and Arduino.

For this example, Raspberry Pi acts as master and sends a single byte to Arduino via I2C.

Arduino, as slave, print out whatever it received. And when requested, send out the last byte received.

Note that:

  • Arduino I2C HAS internal pullup resistors. This could be a problem when talking with devices running 3.3v (e.g. Raspberry Pi)
  • However, the Arduino pullup resistor is so weak (over 50K in Due), we can disable it in software and rely on the internal pullup resistors in Raspberry Pi instead
  • Some references stated that Mega has hard-wired pullup resistors that can't be disabled via software
  • By disabling the Arduino pullup resistors, although not ideal, it does allow Raspberry Pi to be connected to Arduino via I2C directly without a level shifter

References: