First Impressions of the Saleae Logic 16

I decided about a month ago to purchase the Saleae Logic 16 (https://www.saleae.com/logic16) and jump into the world of using my PC as an instrument for electrical engineering.  A few reasons I chose the Saleae Logic 16:

  • Mac support out of the box (I run this on a 27″ iMac and avoid using Parallels / Windows 7 whenever possible)
  • Awesome performance (100 MHz sample rate, 1.8V logic support, numerous protocols…. check out their website for more info.)
  • BEAUTIFUL design.
  • The price at the time was $299, amazing for what this does
  • The Logic Pro’s with analog were not yet available
The unit itself looks very similar to the newest Apple TV.  Photo taken from their website:
Saleae Logic 16
On the back is the USB connector from which power is also pulled.  On the front is a simple 16 channel + 2 ground header into which you plug the included test leads.
 
The software is free to download (and test drive before you buy).  A screen shot from their website is shown below:

Saleae Software

Very clean, does exactly what you’d expect.  Interface was also quite intuitive and I have yet to read a manual or open the help menu.  The basic workflow goes like this:  

  1. Name your channels.  Each test lead is color coded and matches what you see on the screen.  Choose a channel to trigger on (rising edge, falling edge, etc.)
  2. Choose how many samples to collect (this thing can collect a TON of samples, more than i’ve needed for sure) and a sample rate.  The sample rate trades off with number of channels, so for the fastest rates you’ll be limited to fewer channels (again, not really a problem for anything I’ve tried.)
  3. Hit the start button.  The software will begin collecting samples and looking for the trigger.  
  4. Fire up your UUT, or initiate whatever action you’re trying to analyzer / debug in hardware.  You’ll see the trigger capture and the sample buffer start to fill up.  Once all of the samples are collected, you’re waveforms appear on screen and you can scroll / zoom to your heart’s desire.
  5. This is where it gets really fun.  On the right side of the screen, you can see the different “protocol analyzers”.  By assigning your channels to these analyzers, the actual data will be overlaid on your waveforms.  The options are fantastic supported different standards, bauds, endianness, ascii, hex, etc.  
  6. Export your analyzer data to Excel.  This is key when you’re trying to debug complex and/or long exchanges of data.  No need to scroll through seconds of waveform data – just open the Excel sheet and start searching for characters and sequences of data.  

I found two real world applications for the Saleae Logic 16 within a few weeks of buying it – and it paid for itself in time the first day that I used it (possibly making the projects a success overall.)  The first was a prototype piece of hardware that used a Bluetooth LE module talking over UART to a PIC Microcontroller.  The firmware needed some modifications to make sure that data was properly coordinated with the module going in and out of sleep mode.  You can see my setup below, where I just soldered some wire wrap lengths to various vias throughout the PCB:

Bluetooth

I was able to view the UART exchanges within a few minutes of setting up and using the ICD3, I modified and debugged the firmware with ease.

The second project was much more challenging and involved an NFC front end communicating over SPI.  The challenge here was properly conditioning a state machine based on the NFC chip generating interrupts as it went in and out of sleep mode.  Again, just soldered some wires to the SPI vias and other relevant signals and away we go:

NFC

This particular project required exporting all of the SPI data to Excel.  From there, I could dissect the various layers of the SNEP protocol and figure out where the timing errors were occurring.  I can safely say that there is NO WAY I could have done this on an oscilloscope.

So in conclusion:  The Saleae Logic 16 is fantastic.  I highly recommend it, though, the new Pro versions with analog are communing out some time in August.  If you can wait, I’m sure they will be awesome.  I’ll be hard pressed to not purchase one of those as well!