Aardvarks, Beagles and Cheetahs.

This strange sounding menagerie is actually some of the contents of my tool box. They are
such handy tools that I feel I have to blog about them. Actually I only have the Aardvark and Beagle, the Cheetah was more than I needed price and performance wise.


I have spent a lot of time over the last few years working on I2C and SPI interfaces. I always had the luxury of a DSO (Digital Storage 'Scope), MSO (Mixed Signal 'Scope) or LA (Logic Analyzer) to assist me. However even the best LA I had access to was not a protocol analyzer, and could not easily be configured to tell me what transactions were happening. Those who do this for a living know what I'm talking about, you end up counting bits and trying to find ends of bytes, words and packets in a mess of green square waves.

The Beagle allows you to watch what is going on, it is a true protocol analyzer, and for about only $300. The Beagle is a dual mode I2C and SPI monitor. It also can monitor MDIO, which is something I don't yet have to deal with. I2C to 4MHz, SPI to 24 MHz.

The Aardvark is a little different. It can monitor I2C and SPI , but only to 125KHz I2C. Where the Aardvark start to shine is when you want to develop an I2C or SPI slave, the Aardvark can be configured as a master. Here you can drive the bus from your PC, and exercise your target. You can also use it as a golden reference if you are writing the master.

The Aardvark can also drive 8 bits of GPIO, only low speed, but enough to exercise a few inputs on the target board, just what you need to simulate a lot of user input over time. It can also capture about 1000 8bit samples a second.

The software that comes with it is easy to use, and intuitive, even if there are a few funky things in screen refresh cascades (every time data is refreshed all the buttons seem to repaint too). They also provide a full API and code samples in VB, C#, C++, Python, XML you name it.

I actually ended up buying the programmers kit, the bundle with both devices and a few cables, and a developers board. The $500 bundle has already saved me a couple of days work, so it has paid for itself.