Thanks for your reply, Greg. The CD4504 is used on all signal lines to the HV5530s.
Initially only the first HV5530 operated correctly. I did not even think to run clock and data lines in opposite directions. I did experiment using microsecond delays to slow the data transfers on all GPIOs varying the delays for clock and data, but that didn't help at all, even with millisecond delays.Using separate GPIOs for clock and data on each HV5530 solved the problem, so I didn't look further. My question now regards the new Metronome, 15 digit clock that I'm working on. It uses five, HV5530s. The old version separated clock and latch only. All five HV5530s had data connected in series. I don't know why I did it that way, but it has worked perfectly for several years. It seems to make more sense to me, to separate data and clock lines in a group of three, and a group of two. What do you think? On Friday, October 5, 2018 at 3:48:33 PM UTC-4, gregebert wrote: > > I'm starting a separate thread on this topic that was posted from the > introduction discussion > > As with any serial shift-register, the biggest source of trouble is > timing-related, such as not accounting for setup and hold-time requirements. > > *First question*: Are you able to get reliable and predictable data into > the first HV5530 that is connected to your controller ? If not, then the > entire shift chain will be broken, aka "garbage-in, garbage out". > This needs to be solved first. I took a quick look at the code that was > posted and did not see any obvious issues, so I think your setup/hold > timing getting into the first HV5530 is correct. > > Do you have level-shifters between your controller and the HV5530 ? The > logic portion of the HV5530 is intended to operate at 12V, whereas most > controller devices have 3.3V logic levels. > If you dont have a level-shifter, then you are operating outside the > device spec and you venturing into a jungle of unpredicatbles and > uncontrollables. > I know some neonixie members have posted about their good results with > HVxxxx devices operated outside of spec, so if you are adventurous then go > for it. > > All I can say, based on my own experience, is that when you are not > datasheet compliant, expect trouble. I had 3 completely unrelated problems > with a 16-channel A/D converter on my current project, and all of them > turned out to be either my misinterpretation of the datasheet, or my > failure to pay attention to a detail in the datasheet. Once I got those > corrected, it's been fine ever since. > > *Second question*: If the first HV5530 is operating as expected, what > about the next one in the chain ? > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/4e8acb8c-d0e0-4f12-b5b8-81289e15eb62%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
