#7 segment display value freezes after a min or so of inactivity.

1 messages · Page 1 of 1 (latest)

stone kiln
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I have my TM1637 display wired and it correctly displays the aircrafts selected HDG. I turn my heading Rotary Encoder, the heading changes on the 7seg display (and in game) and the aircraft turns. So far so good. But after a short time in flight the 7-seg display no longer changes, it is just frozen on the previous value no matter what I do with the heading bug.

Hitting the reset button on the Arduino sets it right again some of the time, but sometimes it does nothing, and often it just results in a blanking of the display.

storm wolf
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Same symptoms, though. Works for a while and then just stops until you reset the Arduino.

stone kiln
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That does sound similar. The reset button has even stopped working for me now.

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I got it to work again now by adjusting brightness and then selecting upload config

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I suppose that is because it forces the Arduino into a restart.

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...and now its frozen again.

storm wolf
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Yeah, that's probably the reset after upload.

It's either noise, power or connections that's causing this. I guess I will need to just eliminate each of them one by one (somehow?) and see how it goes.

stone kiln
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With regards to Power, the only 2 draws on the 5v are the display and the rotary encoder, so surely that is within limits?

Connections, do you mean it is potentially briefly losing connection and thereby freezing?

storm wolf
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That's one suspicion. Maybe a flaky contact or something that messes up the signal in some way. It seems unlikely in my case because I'm using single core wires and nothing is loose, but it's one item that needs to be checked out.

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Power is also sufficient in my case. I'm only using two segments on a single digit, and it's off most of the time. So it's got to be either noise or bad wires.

stone kiln
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Noise would only be relevant on the data transmitting lines, yeah? Not power or ground?

storm wolf
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Yes. For power I have added capacitors as recommended for the MAX7219, so that should be clean in my case.

stone kiln
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Where is that recommended?

storm wolf
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It's in the datasheet.

stone kiln
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I'm quite new to sll this, the data sheet you mention, is that something that came with the component or is it a document found in this community?

storm wolf
stone kiln
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Thanks for hunting that down.

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I see it does mention capacitors too:

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  1. filtering capacitor between VDD and GND should be arranged on PCB plate as close to TM1637 chip as possible to
    strengthen filtering effect.
  2. 100pF capacitor connected to the DIO, CLK communication port pull-up and pull-down can reduce interference to
    radio communications port.
storm wolf
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Hmm, interesting. The max7219 sheet only talks about capacitors for power. Unfortunately, I don't know enough about electronics (yet!) to understand how to reduce interference. Time to read all about capacitors, I guess 🙂

stone kiln
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I am in the same boat mate. Good luck.

stone kiln
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So after reading further it seems all the required capacitors should be present already on the board that the TM1637 comes on, and looking on the reverse side there are 6 small components labelled R1, R2, C1, C2, C3, and C4. So presumably the 'C' components are the capacitors. Is your display perhaps the same?I did read one blog where the fellow found that the capacitor that was fitted to his board was a grossly incorrect level or capacitance so he changed it, but I have no idea how to see what the capacitance of mine are!

storm wolf
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I'm actually building my own board, so I need to add everything myself 😁

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How are you connecting your display module to the Arduino?

stone kiln
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At the moment, just via jumper cables. Making sure everything works before I do anything more permanent. So the back of your display doesn't look like this? (or similar) with the tiny components incorporated?

20241015_175728.jpg