How Do I Set up the Beagle I2C/SPI Protocol Analyzer to Communicate with Devices of Lower Signal Levels, such as 2.7V?

Question from the Customer:

I am planning to buy your Beagle I2C/SPI Protocol Analyzer. In the Beagle Protocol Analyzer User Manual, the input high voltage signal level is noted as 3.3V with +/-10% tolerance. However, on the target board, the high signal level is limited to +2.7V (the MCU is powered with 2.7V). How can the Beagle I2C/SPI Protocol Analyzer accept +2.7V voltage signals as high logic level signals?

Response from Technical Support:

Thanks for your question! The Beagle I2C/SPI analyzer operates at 3.3V signal levels. An interface is needed to communicate with devices that operate at a lower signal levels, for this we provide - the Total Phase Level Shifter Board. You can use the Data Center Software with both the Level Shifter Board and the Beagle I2C/SPI analyzer.

 Level Shifter Board

Figure 1: Level Shifter Board

It’s simple to provide accurate signal levels between both devices -  just connect the Level Shifter Board between the Beagle I2C/SPI analyzer and the target device. Then run your capture in Data Center to view data from the bus.  Here is a summary of the Level Shifter board features:

  • Level shifting for I2C, SPI, and MDIO signals
  • Supports voltage levels of 1.2V, 1.5V, 1.8V, 2.5V, 3.0V, and 3.3V
  • Supply power to downstream devices
  • I2C speeds of 800 kHz
  • SPI and MDIO speeds of 20 MHz
  • Can be used with the Aardvark I2C/SPI Host Adapter, the Cheetah SPI Host Adapter, as well as the Beagle I2C/SPI Protocol Analyzer

Additional resources that you may find helpful include the following:

We hope this answers your questions. If you have other questions about our protocol analyzers or other Total Phase products, feel free to email us at or submit a request for technical support.

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