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Which Tools Work Best for Emulating I2C MDIO Signals?
Rena Ayeras

Question from the Customer:

I have been using the Beagle USB 12 Protocol Analyzer for MDIO monitoring. However, now I need something to actually drive the bus with transactions to the PHY/switch. MDIO and MDC are open-drain signals, so anything that works with I2C should also be able to provide MDIO.

My question, does Total Phase have a GPIO device than can be bit banged to emulate MDIO? I don't want to have to write scripts to do the bit banging – tweaking the output data on a serial bus. What do you recommend?

Response from Technical Support:

Thanks for your question!  For your application, we recommend the Promira Serial Platform licensed with the appropriate I2C application: I2C Active - Level 1 or Level 2 Application.


High Speed GPIO Output with Level Shifting

The Promira platform has GPIO pins that can be used for bit banging. The frequency of GPIO bit/level switching depends upon the program execution timing of your application. Here is a summary of the features that the Promira platform provides:

  • Integrated level shifting, from 0.9 to 5.0 volts
  • High-speed USB connectivity to the host system
  • Ethernet connectivity
  • Provide total of 200 mA of power to the target(s)


Available I2C Master and Slave Features

The I2C Active - Level 1 Application provides these features:

  • Master at speeds up to 1 MHz
  • Slave at speeds up to 1 MHz
  • Single slave response of up to 256 bytes
  • Program EEPROM or other I2C memory
  • Use up to 4 GPIOs (while using I2C)

The I2C Active - Level 2 Application includes Level 1 features plus the following:

  • Master at speeds up to 3.4 MHz
  • Slave at speeds up to 3.4 MHz
  • Each slave response can be up to 256 bytes
  • No inter-byte delays
  • Program EEPROM or other I2C memory
  • Use up to 10 GPIOs (while using I2C)

Note: The Level 2 application requires the Level 1 application is already installed on the Promira platform.


A Lower Cost Alternative for Driving GPIO Signals

If you don’t need a high-speed tool and use fewer GPIO signals, you could use the Aardvark I2C/SPI Host Adapter, which also has GPIO pin options. The Aardvark adapter supports I2C bitrates of up to 800KHz and works with 3.3V and 5V level signals.

Note: Our I2C adapters follow the specification strictly - any protocol that follows I2C can be used at your end.

We hope this answers your question. Additional resources that you may find helpful include the following:

If you have questions about our Total Phase products, feel free to email us at sales@totalphase.com. You can also request a demo that is specific for your application.

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