I’m looking to set up a loopback so that data sent from an Aardvark^™ I2C/ SPI Host Adapter is echoed. How can I do that?

Thanks for your question! To echo data, you can set up a loopback mode by using two Aardvark I2C/SPI Host Adapters and two instances of the Control Center^™ Software to send traffic between the two Aardvark host adapters.  One adapter will be configured as the master, and the other adapter will be configured as a slave.  The slave unit can then be programmed with the message to “echo” when pinged by the master unit.

Following are instructions to set up and verify a loopback mode in SPI (the instructions are similar for the I2C protocols):

1. Connect the Master I2C/SPI connector of one Aardvark adapter to the Slave I2C/SPI connector of the other Aardvark adapter.
2. Connect the Aardvark–Master USB port to USB port 1 of the computer.
3. Connect the Aardvark–Slave USB port to USB port 2 of the computer.
4. Launch the Control Center Software for the Aardvark-Master on the computer. To do so:

   1. Click Configure Aardvark Adapter → Select Aardvark-Master -> Click OK.
   2. Click Aardvark → Enabled Target Power.
   3. Use the SPI Control section.
   4. Click Master.
   5. Choose the following parameters: Polarity: Raising/Falling; Phase: Sample/Setup; Bit Order: MSB; SS Polarity: SS Active Low; Bit Rate: 1000KHz.
   6. Type 0A 0B 0C 0D in the MOSI message.

5. Launch the Control Center Software for the Aardvark-Slave on the computer. To do so:

   1. Click Configure Aardvark Adapter → Select Aardvark-Slave -> Click OK.
   2. Use the SPI Control section.
   3. Click Slave.
   4. Choose the following parameters: Polarity: Raising/Falling; Phase: Sample/Setup; Bit Order: MSB; SS Polarity:SS Active Low; Bit Rate: 1000KHz.
   5. Type 01 02 03 04 in the MISO message → Click Set MISO → Click Enable.

6. In the Control Center Software for the Master, click Send and then verify the following:

   • The transaction log in the (Master) Control Center Software  shows that the Aardvark – Master sent 4 bytes of 0A 0B 0C 0D, and received 4 bytes of 01 02 03 04.
   • The transaction log in the (Slave) Control Center Software shows that the Aardvark-Slave received 4 bytes of 0A 0B 0C 0D, and sent 4 bytes of 01 02 03 04.

For additional information, please refer to the following documents:

Aardvark I2C/SPI Host Adapter Quick Start Guide

Aardvark Adapter User Manual

Control Center Software User Manual

Total Phase Products

Product Selector Guide