HP 165xx analyzer cards threshold level - Page 1
Forum section: electronics / testgear

author: davorin
author_rank: Unknown
timestamp: January 24, 2015, 10:42:04 pm
content: Evnon' (o;One question popped into my mind lately...if it is possible to use for example the 16510B or 16555A cards to analyze RS232 level signals...For example the 16555A datasheet mentions that the pod input level can be 40V peak-peak....and the threshold level can be set between -6V and +6V...So theoretically I can just set the threshold just to 0V and directly hook up to RS232 signals?I guess decoding the stream is out of question (o;

author: helius
author_rank: Super Contributor
timestamp: January 24, 2015, 11:20:34 pm
content: Quote from: davorin on January 24, 2015, 10:42:04 pmThere was some discussion of protocol decoding software in an old thread:https://www.eevblog.com/forum/testgear/hpagilent-16500b-software/tldr; there was a MS-DOS development package that created "inverse assembler modules" that you could then load on the 16500. I guess that could be used for serial protocols too, but I don't really know.All things considered it would be much easier to just get a Bus Pirate for serial protocols

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: January 26, 2015, 02:23:35 pm
content: there are dissasemblers 'inverse assemblers' around to display the decoded streams.

author: davorin
author_rank: Unknown
timestamp: January 26, 2015, 02:47:23 pm
content: Okay..thanks (o;But my primary question was more about the levels I can feed into the analyzer cards...

author: mike_kawasaki
author_rank: Contributor
timestamp: January 26, 2015, 06:15:20 pm
content: Quote from: davorin on January 26, 2015, 02:47:23 pmThis is going deep into my memory (my first job at HP, 26 years ago, was the Product Support Engineer for the 16500 and 1650)...* Yes, a RS-232 signal can easily be managed by the 16500A acquisition cards. The threshold can be set to +/- 9.9V with .1V increments; while the dynamic range is +/-10V from threshold. Although RS-232 swings to +/-12V you are really just focused on the threshold level. As you noted the max voltage is +/-40V.* The debugging/disassembly was done through a bus interface 'preprocessor'. The model number is a 10342B and maybe can find one on the used market very cheap. The 10342B basically converted different bus interfaces to the logic analyzer pods; plus the configuration software and the disassembly software. I think it converted RS-232, RS-449 and HP-IB.Hope this helps!Mike

author: davorin
author_rank: Unknown
timestamp: January 26, 2015, 06:21:30 pm
content: Hello MikeThis helps me perfectly...many thanks :-)Well..inverse assembly is not a current option....more important was the fact that I could connect one pod to rs232 levels while the other goes to TTL/CMOS levels...all coming from the same board...this saves me of hooking up a DSO in parallel...

author: PlainName
author_rank: Super Contributor
timestamp: January 26, 2015, 09:10:19 pm
content: QuoteYes, but note that RS232 levels are +3V to +25V and -3V to -25V. There is a band of hysteresis between +3V and -3V - it would be possible to have a dodgy signal which would look fine when sampled at 0V without hysteresis.Having said that, practical experience suggests that real kit will handle seriously dodgy signals just fine, so...