It's true most micros won't run instructions that fast, but outputting a count of pulses can often be handled by a timer peripheral at anything up to the system clock rate. Alternatively a microprogrammable peripheral such as the RP2040 PIO, Beagleboard PRUs, or the venerable Motorola TPU.
On Thu, Jun 13, 2024 at 4:26 PM gregebert <[email protected]> wrote: > I'm planning a similar approach with the HP5245L, but instead I will run > the counter with a 10-second gate. The gate signal is an *output* from the > counter, and while the signal is active, it just acts like a regular > counter. So, all I need to do is wait for gate to go active, send a stream > of pulses (up to 235,959 of them), and they will display the time. > > The odd thing about the 5245 is that the display is on while counting; > annoying if you are measuring frequency but just what you need for a clock. > After the initial count is displayed, which is pretty fast at 50Mhz (less > than 5msec), the next 9+ seconds only require a single pulse to advance the > seconds *in most cases*. When there is a rollover for the next minute, > you need to send 41 pulses so that xx:x1:59 becomes xx:x:2:00 . Similar > exceptions for ten-minute, hours, etc. At midnite, this trick wont work so > you may as well flood the device with an erratic burst of pulses to make > most of the digits roll. > > Since a 50Mhz pulse-output is too fast for a cheap microcontroller, it > will be done from an FPGA. > > Of course I wont keep this thing running 24/7 because of the noise and > wasted electricity. But at least I will get more usage out of th3 5245L. > > On Thursday, June 13, 2024 at 7:23:51 AM UTC-7 Adrian Godwin wrote: > >> Interesting idea. >> I'd speculate that the accuracy problem where the counter failed to see >> some pulses is perhaps a synchronization problem. If the pulse-counting >> method worked by generating a variable number of pulses at 240kHz then they >> should always be visible to the counter as long as that's within it's >> range. But if the gate period of the counter didn't coincide with the >> gating of the pulses at the generator, you would get variable results. And >> there's no obvious way to make them synchronise without stop/start signals. >> >> >> On Thu, Jun 13, 2024 at 3:04 PM Paul Andrews <[email protected]> wrote: >> >>> Why not both? Here is my partially successful attempt to display the >>> time on a frequency counter by generating the correct frequency that would >>> result in the time being shown in the frequency counter. I had forgotten >>> about this until I read this thread: >>> >>> >>> https://www.nixies.us/2018/03/25/display-the-time-on-an-old-frequency-counter/ >>> >>> On Thursday, June 13, 2024 at 5:53:32 AM UTC-4 Adrian Godwin wrote: >>> >>>> I much prefer Nixies in functional equipment rather than for their own >>>> sake. And while displaying them in a clock is fine, there are other types >>>> of clock to cherish too, leading to a loss of space. And since I can build >>>> a clock myself, other functionality is attractive (admittedly I wouldn't >>>> pay $300). >>>> >>>> It's a pity there aren't a lot of devices other than counters and DVMs >>>> to find - I already have Philps, Racal and Avo examples. I'd like to find a >>>> nixie-based measurement system such as a Heidenheim. >>>> Are there any other types of instruments that were made ? >>>> >>>> >>>> On Thu, Jun 13, 2024 at 2:03 AM <[email protected]> wrote: >>>> >>>>> Re: [neonixie-l] A bit $teep for a DMM >>>>> On Wed, Jun 12, 2024 at 11:57 AM Mac Doktor <[email protected]> >>>>> wrote: >>>>> >>>>>> What makes this DMM so valuable? There are only four tubes to yank >>>>>> out: >>>>>> >>>>>> https://www.ebay.com/itm/405017664588 >>>>>> >>>>>> >>>>>> It is a FLUKE, you would only Yank the tubes to clan the pins and >>>>>> remove the dust from the sockets... then reassemble carefully and bow >>>>>> down >>>>>> in Veneration. >>>>>> >>>>> -- >>>>> >>>> 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 [email protected]. >>>>> >>>> To view this discussion on the web, visit >>>>> https://groups.google.com/d/msgid/neonixie-l/194ac98d77051b3026a5ca51c003969b%40zeusprune.ca >>>>> <https://groups.google.com/d/msgid/neonixie-l/194ac98d77051b3026a5ca51c003969b%40zeusprune.ca?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- >>> 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 [email protected]. >>> >> To view this discussion on the web, visit >>> https://groups.google.com/d/msgid/neonixie-l/b082f74b-146c-48b7-aa06-f325bbceec92n%40googlegroups.com >>> <https://groups.google.com/d/msgid/neonixie-l/b082f74b-146c-48b7-aa06-f325bbceec92n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- > 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 [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/2fdbf720-532c-4590-b187-0fa16e79a999n%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/2fdbf720-532c-4590-b187-0fa16e79a999n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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