Actually - I just looked through an example over
at: https://www.hackster.io/doug-domke/multiplexed-nixie-tube-clock-759ff5
... and it all seems fairly understandable, have I overthought this?
- Richard
On Wednesday, 1 November 2023 at 09:22:03 UTC Richard Scales wrote:
> The time has come
Hi,
It’s not difficult. My fumbling attempts at a Nixie clock some time ago
used a 4:1 multiplex ratio, using four digits and only one decoder. I used
the same MPSA42/MPSA92 driver as your example. My multiplex function was
called at 100Hz, so each digit was refreshing at 25Hz. It doesn’t
The time has come when I need to get a handle the dark and mysterious art
of multiplexing.
I have an understanding of what needs to happen though am mostly at a loss
of how to implement it.
I am broadly assuming that I should be using some kind of interrupt routine
to make the actual display
Hi,
I offer you one caution with the ESP8266 boards - almost everything is
implemented in the libraries in software rather than onchip hw.
That means doing things like updating addressable LEDs can cause the
multiplexing to glitch slightly because of the need to send LED data at
strict timings.
Hi Richard,
Remember that the Microchip chips (HV5530 etc.) are just *high voltage*
port expanders. You can use them to control the MPSA42/MPSA92 transistors
too, so assign a bunch of their pins to the cathodes and some to the
anodes. Slight wrinkle is that that specific chip is open-drain, so
Hello,
if an ESP8266 is not enough powerful, the ESP32 will do the job.
the ESP_WROVER can be a good platfom.
you should have a look to Mose's work on https://neonixie.com/Z57XM6DV2/
the code is a bit "strong" as it can be used both on an 6 IV-9 clock and a
more traditional 6 digits Z57,
@Paul - I have no idea of the sense of scale and the relative times taken.
If I were to hang another HV driver on the chain with associated
electronics to switch the HV, is there going to be enough time to do the
following:
Set the bits for the segments required- I add this step just in case
I'm using a Pico in my project, I run the tube driving routine on one core
and everything else on the rest so it doesn't suffer from slowdowns.
I've had to introduce a delay to slow it down to a 1ms refresh!
Craig
On Wednesday, 1 November 2023 at 15:47:33 UTC gregebert wrote:
> Multiplexing
Many thanks Nick.
Unless anything else comes to light I think I will forge ahead on that
basis. I want to drive 15 segment panaplex displays (16 including the DP)
so plan to use HV5530 or similar driver for the segments, probably two of
them. Then the same MPSA42/MPSA92 driver arrangement for
@David - I should have said - I'm not against LEDs and Nixies in any way -
just not for this project - it is for panaplex displays which don't really
lend themselves to backlighting - though I have done something recently
with FFD21 Minitrons (which are equally opaque) by using side facing leds
So is it an issue towards tube life or nothing to worry about?
Craig
On Wednesday, 1 November 2023 at 05:51:23 UTC gregebert wrote:
> I'm speculating that in order to get the higher current for multiplexed
> operation, the increased voltage was enough to coax a bondwire into
> glowing. I have
Well you don't wait in an ISR, so in the ISR it is really just:
- figure out what bits to set
- set them
- figure out when you next want the ISR to trigger
- arrange for that to happen
I've only ever set 64 bits in an ISR so I've no idea if it would break if I
tried to set more, but make sure
@David - many thanks for that caution though there will not be (nor ever
will there be!) any LEDS for this project!
@Pauld - thank you - I had thought of that but I was endeavouring to keep
the code inside the ISR to an absolute minimum so thought that it would be
best handled outside of it and
Where it all leads to, I think, is that you no longer need to do custom
logic design, and you can skip the need for certain ICs such as realtime
clocks, by switching to a software-based design, whether it's RasPi,
Arduino, or any other embedded controller.
It's gotten so "bad" that I rarely
Dual Core Processors - now my head really hurts - I mean - I love the idea
but don't think my programming skills are ever going to stretch that far!
Just woke early (03.13) - still full of Covid and had a wrestles thinking
session on this during which I reminded myself of all the success that I
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