> That's my first post, but I hope I get an answer to my huge beginner problem.
> So, I've recently started to build my own Nixie clock. I have four LC-531
> nixie (Polish production) gathered from old Unitra Multimeter. All of them
> works fine when I'm trying to connetct it to HV source (Voltage converter
> 9V->150-220V - schematic) I'm using ~180-190V and 10k resistor (is it good?).
Depends on how much current those nixies want. I'd probably start with 15k or
so.
> Few days ago I finally get some 74141 and I was trying to test it, so I
> connected it to ATtiny2313 like this:
>
> and program MCU with that code. It should count on Nixie lamp from 0 to 9 (2
> sec per digit).
There are some quirks when reading from a port on an AVR. Instead of
"PORTB += 1", you might try "PORTB = i". Since it works with LEDs, I
don't think that's your problem here. If you really want to be cute with it,
you can just make your entire loop "for (PORTB = 0; PORTB < 10; ++PORTB) {
delay(2000); }".
> Double checked all my connections and as the result I've got Nixie lamp with
> all digits glowing in the same time.
This can happen for a variety of reasons.
> I also checked 74141 using LED diods (+ to 5V and - to 74141 outputs) and it
> works fine (diodes light one after another)
That's a good idea. It lets you see that the problem isn't your AVR code, 5V
power supply
connections, or data wiring.
> Any suggestions what I'm doing wrong? It seems to in some way all outputs are
> connected to GND when using HV to my nixie (works fine with LED).
There are a few possibilities here. My first guess is that your voltage is
high enough
that the clamp diodes in your 74141 are conducting, causing additional cathodes
to
light. Do you see changing cathodes getting brighter? Can you try turning
down your
high voltage supply some?
Another possibility is that your HV ground isn't connected to the 74141 ground,
which
can cause a variety of issues.
It could also be that your HV supply is causing interference with your digital
logic.
If there's a way to put your HV supply a meter or more away from the rest of
your
circuit, and power the HV supply with a different source than your logic supply,
it's worth doing. Power supply decoupling capacitors near each of your logic
chips is a really good idea too. 0.1µf between +5 and ground, with short leads,
one each for the ATTINY and 74141. Digital logic cares deeply about clean
power and can do all sorts of bizarre things if it doesn't get it. Those little
capacitors cure a host of ills.
What happens on the nixie if you mash the reset switch? That should freeze the
AVR if it's zipping through digits. Unfortunately, I think it also tristates
the I/O
lines, which won't help you. You could try hanging a LED off one or two of the
I/O lines connected to the 74141 - see if those are changing predictably. It'll
probably throw the logic levels off, but at least you can see if the AVR is
still
behaving.
Alternatively, you could hardware your 74141 to a specific value (like "2") by
tying
its inputs to +5 and ground as needed, verify the expected LED lights, then try
it
with the nixie.
> EDIT If I'm missing any electronic part here, please provide me info how to
> connect it and how it will help, I 'm Software Engineer and unfortunately,
> I'm not good in whole electronic stuff (yet :) )
You've got the right idea - start small, test with LEDs, and move up to nixies.
You already
have your HV supply working, which is good - a lot of people have trouble with
those.
You have your AVR code working too. You're really close.
- John
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