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Products => Test Equipment => Topic started by: pelule on October 21, 2015, 06:48:53 pm

Title: How to use Zeroplus LAP-C Logic Analyzer as signature analyzer
Post by: pelule on October 21, 2015, 06:48:53 pm

Hi
I need a signature analyzer to test/repair the CPU board of my HP 8116A.
http://www.radio-electronics.com/info/t_and_m/signature-analyzer-analyser/basics-tutorial.php (http://www.radio-electronics.com/info/t_and_m/signature-analyzer-analyser/basics-tutorial.php)
As it is in principle a level triggered start-stop 16-bit shift register I think it may possible to use the Zeroplus LAP-C Logic Analyzer for that function.
Does has anyone experiance with that?
BR
PeLuLe

Title: Re: How to use Zeroplus LAP-C Logic Analyzer as signature analyzer
Post by: Le_Bassiste on October 21, 2015, 07:50:11 pm

the trigger capabilities on the LAP-C are quite unimpressive, so you may want to trick a little bit with the bus trigger feature. i simply take _all_ channels and _all_ busses into another bus and call it trigger-bus. then, i set BUS TRIGGER SETUP to an event on trigger-bus, after which i assume the interesting data will follow. i also set data acquisition to no compression, and sampling rate to the lowest possible rate (take 10 x highest frequency on probed signals as a starting point). then, let the LA do a one-shot. then, look for the signature in the captured data stream with FIND DATA VALUE. there, "ACTIVATE THE FUNCTION OF CHAIN-DATA FIND", type in the name of the bus you want to analyze (not the trigger-bus) and give the signature you want to find.
(any better idea than this very much appreciated!)