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How do I Provide Lower Signal Voltage Logic and Power Levels to SPI Target Devices?

Question from the Customer:

I need some help with programing and testing SPI chips on my board. I am using the Aardvark I2C/SPI Host Adapter with the 10-Pin Grabber Clip Split Cable. I am new with the these tools and have some questions:

  • What is the purpose of the NC/+5V line on the cable?
  • The signal levels of my SPI target devices are 2.5V. How does the Aardvark adapter interface with that signal level?
Response from Technical Support:

Thanks for your questions! The NC/+5V line on the 10-pin grabber cable  is be used to deliver the +5V power supply from the Aardvark adapter to the target device.

Pins 4 and 6 (NC/+5V) of the Aardvark adapter can provide +5V power supply to the target system. You can enable these signals by using the following Total Phase software tools:

If you would like to learn more about the SPI pins and signals, please refer to section 2.1.6 of the Aardvark I2C/SPI Host Adapter User Manual.

Aardvark I2C/SPI Host Adapter Figure 1: Aardvark I2C/SPI Host Adapter

For your voltage level question, the Aardvark adapter I2C/SPI signal logic is 3.3V. To adjust that voltage we recommend using the Total Phase Level Shifter Board with the Aardvark adapter. The board  provides I2C/SPI voltage level shifting from 3.3V to  1.2V, 1.5V, 1.8V, 2.5V, and 3.0V, as well as power to the target device.  For information about using the level shifter board, please refer to the knowledge base article Programing I2C EEPROM Using Aardvark Adapter, the Level Shifter Board and the Control Center Serial Software.

Alternatively, you can use our new PromiraTM Serial Platform with the SPI Active - Level 1 Application.  The Promira platform is our latest device for I2C and SPI protocols and has integrated level shifting; there’s no need to connect to an accessory level shifter board.

Promira Serial Platform Figure 2: Promira Serial Platform

The Promira platform supports additional advanced features:

  • Operates as an I2C master up to 1 MHz
  • Provides 200 mA to a power a target
  • USB 2.0 and Ethernet connectivity for faster downloads
  • Operates with SPI devices with the SPI Active - Level 1 Application

For additional information about the Promira platform, please refer to the Promira Serial Platform User Manual.

Additional resources that you may find helpful include the following:

We hope this answers your question. If you have other questions about our host adapters or other Total Phase products, feel free to email us at sales@totalphase.com, or if you already own one of our devices and have a technical question, please submit a request for technical support.