look , you can't really blame this thing for not having a trigger system. not at this price point. their software is pretty clever and they have a nice visualisation of many protocols. true, their are hampered by the hardware. but then again all these cypress based designs are in the same category ( Usbee , Salae , Logic and some others )
The ChronoVu
http://www.chronovu.com/ for example is a different animal. that one uses a CPLD and on-board SDRAM to capture at up to 100Mhz. it does have triggering capabilities albeit not sequential triggering. Then again at that price point you still can't complain.
A real logic analyser with sequence triggering , fast , deep memory and advanced decoding ( like assembly ) is going to cost you an arm and a leg and there is much more involved in such a beast.
here is a VNC session connected to my logic analyser :
One of the 'blades'
This is a 16702B running HP-UX on a PA-Risc machine. The empty chassis ( so just the computer / display section ) of that thing was over 30K$ when new 10 years ago. The blades depend on their functionality but a blade holding 4 Meg and clocking in a 1Gsa/s pushes another 35K onto the machine
The blade above is a 500MHz 4 meg deep 68 channel acquisition card. It can do state and timing and hes sequentiel trigger.
I have another balde with 'advanced trigger' capabiltities. The user interface is like a flowchart. you can make really long trigger scripts.
1)- wait for pattern a to occur
2) if within time(x) pattern b occur then trigger
3) if within time y() from (1) pattern C does not occur then :
4) scan for pattern d , followed by pattern e ,f,g,h and if withing timestamp e from f there is no activity on input 4 then trigger with 70% pretrigger buffer.
for each step you can set masks and for each time stamp you can do shorter,longer , within or without.
you can do absolutely insane triggering with that machine. then again , take a look at the massive asics with heatsinks on their back ... that is not stuff you prop in a simple FPGA...
The machine can run cards in lockstep with each other , there is also a pattern generator card ( which i have too ) so you can generate stimuli as well , and the generator also has looping and sequencing capability , there is a scope card that basically lets you add 2 analog 1GHz channels. With its expansion chassis you can have 10 blades in this box. And if that is not enough there is the possibility to connect the analyser on the LAn and pair it remote with one or more infiniium oscilloscopes. Just plug in the IP addresses and the logic analyser goes and fetches the traces of the scope and displays it in time-step with whatever it captured.... there is a module to sync the scopes and analyser in time.
i hooked up my 54832D ( 1GHz 4 analog + 16 digital infiniium with 4Msa/s and 8 Meg memory) to this analyser and the i could simply scroll through the trace buffer while the analyser grabbed the analog data from the scope and visualised it on the same screen. everything was there : the 4 analog traces of the scope , the 180 or so digital traces of the anayser linked in various buses. it didn't even slow down.
pretty impressive given that this is a PA-risc running at barely 75MHz running a full bown Unix system with X-client
The analyser as it sits would have costed well over 200K$ when new. Pretty impressive stuff, even today, for a 15 year old machine... you should see the new machines like the 1690x ...
So all in all i think the little Salae does a good job for its price. I like the software , it reacts fast is intuitive and the packet decoders work well. ok there is no triggering but you can compensate using deep buffer memory and hope you catch everything in there.
Now, on the other hand a 'lister' like dave's 3000x scope has would be welcome.... That is especially handy for serial protocols. you can immediately see : here's a missing ack , here this got sent there etc. Clicking a line in the lister scrolls the traceview to that timepoint.
I got a demo yesterday of the new 4000x series scope. Pretty slick machine. I went to the boss afterwards and told him to buy me one.