Interfacing 5V and 3V3 I2C busses You can't connect a 5V I2C bus (e.g. an Arduino board) to a 3V3 I2C device (e.g. a Raspberry Pi) without damaging it, so in this situation you would need to its the 3.3V I2C bus to connect to a 5V I2C device.  This means no over voltage damage […]

I2C Clock Speed 400kHz means the clock speed for a complete high low clock sequence.  So 2.5uS per cycle, 1.25uS per high or low clock edge. Pull Up Resistors Minimum current that all devices must be able to sink = 3mA This sets the lower resistance limit on the pull-up resistor. 1K7 for a 5V system […]