My search for the perfect personal logic analyzer

When buying hardware, the following picture is good to keep in mind:

I've bought (and gotten rid of) several cheap bikes already.  If you are minimalist like me, you only keep the good ones, so if you already know that you will not put up with cheap stuff, it's cheaper just to just buy the good one from git-go.  The problem is that you often do not know if you are going to stick with something at first, in which case it makes sense to minimize the up-front investment by buying cheap.

My first drug: oscilloscope

But globalization, industrialization, and other marches of technology (think Moor's Law) has driven down the cost of comparable hardware, and brought down the cost of just trying something.  I benefited from this when I bought my personal oscilloscope (Hantek DSO-2250 USB) from eBay a few years ago, for around $200 back then.

They hook you with free stuff

I solved many problems at work with my Hantek DSO-2150, but ran into a case where I needed 6 channels.  A EE friend recommended the $10 Saleae knockoff from eBay.  I found out that it could not really capture at 24 MHz, but still what a great deal!  But I kind of felt guity about using the Saleae SW.

I was hooked, but was too cheap (see the picture above)

When I needed faster speed, I upgraded to Hantek 6022BL for around $80.  I already knew that logic analyzers are in general more expensive than oscilloscopes, so I have only myself to blame for forgetting the above picture: despite its advertised name, Hantek 6022BL is NOT a true logic analyzer, and a worse scope than DSO-2250.  I wound up giving it away to a colleague who needed a very basic scope.

Then I had a taste of the good stuff

I considered $80 a reasonable "discovery fee", and then got my company to pay for a Saleae Logic Pro 16 (about $650, after CA tax).  I was smitten by its ease of use, put it to a good use most recently for an image sensor bringup work.  I found Saleae Logic Pro 16's limitation of 100 MHz bandwidth limiting, but Saleae's founder/CTO Mark explained that I would not get any more speed any time soon (we discussed using the Thunderbolt connector, and why I don't get the full USB 3.0 bandwidth from the logic analyzer).

My sweet spot

I am so hooked that I am now looking for a personal logic analyzer.  By using the Saleae Logic Pro 16, I learned my requirements for the logic analyzer:

1. I cannot go back to fewer than 16 channels.  32 channels would be nice, but a luxury that I can probably do without.
2. Because I do some about of high performance FPGA work, where 200 MHz clock rate is not unusual, I would like the maximum sample rate to be >= 400 MHz (read about the sampling theory).
3. All things being equal, ability to capture long history enhances debugging productivity, so minimum of 10 ms capture at full rate is desired.  10 ms of 400 MHz is 4M data points for 1 channel.  If a 16 channel logic analyzer had to store that in a local memory, that would require 64 Mbit buffer.

The candidates​

After poring at the choices, I narrowed the selection to the following:

• Chronovu: $244, 200 M samples/sec, 16 channel, 64Mb buffer.
• Zeroplus LAP-C 16128: $439, 75 MHz, 16 channels, 2Mb buffer.
• Hantek 4032L: $185, 400 MHz, 32 channels, 2 Gb buffer.  125 MHz input signal BW.
• Intronix: $389, 500 MHz, 34 channels, 64 Kb buffer.
• DSLogic, $100, max input 400MHz.  50 MHz input BW limit (in which case, what is the point of sampling at 400 MHz?), 16 channels, 256 Mbit buffer.

It appears that Chronovu and Zeroplus are too slow, and Intronix is has too small a buffer, so I have to choose between DSLogic and Hantek 4032L.

Winner: Hantek 4032L

For less than twice the price of DSLogic, which limits the maximum input BW to 50 MHz, Hantek 4032L will let me look at 32 channels.  It does NOT have the state mode feature (where clock is provided by an external source--one of the channels), but its fast sample rate makes up.  Only video FPGA work requires faster clock than 100 MHz, so this logic analyzer will do.