How Do I Debug SMBus Communication between my Aardvark I2C/SPI Host Adapter and a Smart Battery Pack?
2015-09-02
Rena
Question from the Customer:

I am using the Aardvark I2C/SPI Host Adapter and I am trying to connect it to the SMBus compatible NL2020 Standard Smart Li Ion Battery Pack. Unfortunately, I’m not getting an acknowledgement from the battery after executing a read/write command.  Here are the details of my application:

  • The address of the battery is 0x16.

  • I have the Aardvark adapter’s SCL connected to the battery’s clock, and the SDA line to the battery’s data line, and ground to the battery’s negative terminal.

Can you tell me how to use the Aardvark adapter to communicate with my device? My understanding is that the Aardvark adapter is SMBus compatible.

Response from Technical Support:

Thanks for your question! The Aardvark I2C/SPI Host Adapter is definitely compatible with the SMBus protocol, since SMBus is based on I2C. Without knowing the exact commands that are being sent and the instruction set of your NL2020 device, it would be difficult to pinpoint the exact issue. Your command may not be formatted correctly, and therefore unrecognized by the device. On the other hand, it’s possible that the Aardvark adapter is correctly sending data, but the device is not properly configured to respond to that data.

To get a better idea of what is happening on the bus, we highly recommend using our Beagle I2C/SPI Protocol Analyzer, which supports SMBus decoding, to get more visibility and information.

Beagle I2C/SPI Protocol Analyzer Figure 1: Beagle I2C/SPI Protocol Analyzer

The Beagle analyzer works as a passive tap onto your SMBus lines and displays all the bus traffic sent between the Aardvark adapter and your device in real-time.  It is a great tool to use to debug the communication between masters and slaves, and with the Data Center Software, it allows you to search and filter through the bus data in real-time. 

Data Center Software views live data Figure 2: Parsed SMBus Traffic as Seen in Data Center Software

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 submit a request for technical support.