HP/Agilent Logic Analyzers with 2 Clocks per 16 Channel Probe? - Page 1
Forum section: electronics / testgear

author: NF6X
author_rank: Unknown
timestamp: October 08, 2025, 08:33:43 pm
content: I'm commissioning my Agilent 16700B logic analyzer which I've configured with three 16555A cards, providing a wild 192 data channels and 12 clock channels. Why would I want so many channels?I play with old 16-bit and 32-bit minicomputers whose CPUs span multiple cards, and debugging those chews up channels fast.More is better.It's wild! It's silly! It's just crazy! So why not?With so many channels, I figure it would be nice to make a little exerciser dongle that tickles all of the clock and data lines on a probe cable, so I can quickly do a confidence check to make sure there aren't any bad channels hiding in there. I'm studying the manual for my HP 01650-63203 100kOhm Termination Adapters. It defines two clock pins on both the 20 pin and 40 pin ends, as shown in Figure 5:However, all of the logic analyzers it lists as being compatible with, as well as the 16555A cards that I have in my 16700B, provide one clock input per 40 pin probe cable:For example, on the 01650-61808 flying-lead probes that came with my 16555A cards, there's a single-pin ground lead in the position for pins 5 and 6 where the second clock input isn't. The housing would accommodate a 2-pin clock/data lead in that position if the analyzer used pin 5 for a second clock.Were there any HP/Agilent logic analyzers which had two clock inputs per 40-pin 16-bit probe cable?The manual notes that the 01650-63203 replaces an earlier 01650-63201 termination adapter which does not connect the +5V power lines from the 40 pin pod cable to the 20 pin target connector. I wonder if that implies that there may have been logic analyzers which didn't provide a +5 power output for the earlier one to connect to.Were there any HP/Agilent logic analyzers which did not provide +5V power on pins 1 and 39 of their 40-pin probe cables?Neither consideration matters for my own logic analyzer, but as long as I'm making the dongle I'd like to understand what variations existed among the logic analyzers which used the same style of 16-bit, 40-pin probe cables. After all, I'll make a multiple of 3 dongles if I use OSH Park for the PCBs, and maybe there are two other logic analyzer nuts like me who would be interested in having one?Yes, I know that I need much better lighting on my lab bench. Please feel free to roast me and/or provide good suggestions. :)

author: gslick
author_rank: Frequent Contributor
timestamp: October 08, 2025, 09:53:55 pm
content: Quote from: NF6X on October 08, 2025, 08:33:43 pm16540A/D master cards,and maybe 16541A/D expander cards. The special clock/ground lead is the 16540-82101.

author: gslick
author_rank: Frequent Contributor
timestamp: October 08, 2025, 10:08:33 pm
content: Quote from: NF6X on October 08, 2025, 08:33:43 pmIf I remember correctly how this works, you only get the 4 clock channels on the master board that can be used as actual clock channels for state mode. The other 8 clock channels on the two expander boards can only be used as additional data channels in timing mode, and not at all in state mode. I'd have to boot up an LA to verify I remember that correctly.If you want/need more than 4 clock channels for state mode, I think the best you can get is 6 clock channels on a 16550A or 16712A.