MAX7219 matrix display issue to get it work

[rige]

Hi everyone,
I bought MAX7219 dot matrix module from Aliepress and I tried to make it work with NodeMCU - but struggling to make it work.
https://www.aliexpress.com/item/1005002 ... 1802G8LqrA

binary: ESP_Easy_mega_20230409_display_ESP8266_4M1M
SPI enabled, wired CLK - D5, DIN - D7, CS - D4.

The issue is that display shows nothing.
I had tried build 202200809 before, but it was the same.

Sometimes when I touch back part of display, one or more segments light on or off. I tried to display clock, but no luck at all.
I tried also another board ESP32 (different wiring), but the same behaviour - no text displayed.
Basically nothing is displayed. It looks the same way as the display module would have only VCC and GND connected.

Any idea what could be wrong in my setup?

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[TD-er]

As far as I know, those are essentially a shift register, so there is a direction of the data flow.
Did you wire it from the right side?

Maybe the modules need 5V to operate?
Just make sure to use a level converter then, as described here: https://espeasy.readthedocs.io/en/lates ... le-voltage

[Ath]

Hardware type should, in 99% of all situations, be set to FC16 (I already made that default in the code, but that's not merged yet). All modules I've obtained from several Ali suppliers use that layout.

Powering it from 5V might be required indeed and use a level shifter to protect the ESP, didn't test using only 3.3V as I didn't own a powerful enough power supply (ordered 1 last week that's arriving soon ), but these MAX chips don't seem to work very well at 3.3V, though that may depend on the actual brand of chips used.

[rige]

There are many manuals and videos with ESP8266 and MAX7219 that describe 3V power - e.g. https://mytectutor.com/how-to-control-m ... t=cmp-true

I tried 5V for sure (without level shifter - to be honest I have no idea what should I use). I read somewhere that ESP8266 should be 5V tolerant on GPIOs.
Unfortunately there was no change at all.

I tried FC16 - no change.

The display 4 modules came with PINs only on one side with description "DIN" - so I assume it was built ready to use.

I see posibility that I have just not working LED module. Probably I will order one module 8x8 LEDs with MAX7219.

[rige]

So I bought https://www.aliexpress.com/item/1005003 ... 1802bNuBin
and it works fine for me (on 3,3V and then I tried 5V as well).

I will try to order another 2x4 module and I am curious if it will work.

[Ath]

When powering the display with 5V, you really should use a level converter, as explained in the documentation. Pulling 3.3V from your ESP might work for a single module, but it won't be able to power multiple modules (the 3.3V converter will be overloaded and either burn out or get really unstable).
This very similar thread emphasizes the reasons for using a level converter. These level converters (best to get the 4-channel model) are really cheap (there's 10 in the package!) so that shouldn't be a problem.