Support Question of the Week: Using the Aardvark I2C/SPI Host Adapter with a Level Shifter Board

Q: I'm working with the Aardvark I2C/SPI Host Adapter, and I would like to use the Aardvark host adapter with a 1.8 volt slave device. My I2C device lines are 3.3 volt tolerant. I tried to disable your pull-ups and use an external pull-up resistor to 3.3 volts, but this doesn't seem to work. Can you help me out?

A: Thanks for your question! We can certainly help you with your I2C device setup.

The Aardvark I2C/SPI Host Adapter operates at 3.3V signal levels, but is 5.0V tolerant (e.g. it will function properly and will not be harmed by voltages to 5.0V). As you indicate, the Aardvark can function in I2C or SPI modes, and has GPIOs. The responses below apply to I2C and SPI.

To operate the Aardvark with lower voltages, it is necessary to use an auxiliary board along with your Aardvark host adapter. Our Level Shifter Board would need to be inserted between the Aardvark adapter and the target I2C device to communicate with devices that operate at a lower voltage. Using the level shifter board will also provide correct I2C/SPI signals to both devices.

The Total Phase Level Shifter Board, which does voltage level translation from 1.2V to 3.3V (discrete values of 1.2V, 1.5V, 1.8V, 2.5V and 3.0V to 3.3 V) for the Aardvark I2C/SPI Host Adapter. Engineers can use the level shifter board to perform level shifting for I2C bus signals and supports I2C bus speeds of up to 800 kHz. Additionally the Level Shifter Board supports SPI speeds up to 20 MHz.

Animated diagram of the Level Shifter Board

If you need to monitor all traffic on an I2C bus or SPI bus, you can use the Beagle I2C/SPI Protocol Analyzer.

We hope this answers your question! Good luck with working on your I2C slave device and please let us know if you have any questions at or

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