Common Issues - READ THIS FIRST

[mrcodetastic]

There are so many different types of HUB75 LED panels that the 'default' configuration of this library will not work in some cases.

Below is a list of commonly reported issues, and solutions. If your issue is not one of those listed below, raise a seperate new issue.

Issue 1: GHOSTING [#132][#145]

or

Solution: Increase the latch_blanking (i.e. the time between clocking data to the panel and then turning the LEDS 'on'). Some panels can't handle the speed of this library.

mxconfig.latch_blanking = 4;
mxconfig.i2sspeed = HUB75_I2S_CFG::HZ_10M;

and reduce brightness as well

  // let's adjust default brightness to about 50%
  dma_display->setBrightness8(128);    // range is 0-255, 0 - 0%, 255 - 100%

and ensure wiring is AS SHORT AS POSSIBLE. Use the shortest jumper cables from the HUB75 to the ESP32. Avoid this:

Example video of what happens with long wires: https://www.youtube.com/watch?v=jWXfdtsxo0o

Issue 2: Vertical output isn't aligned in the two panels of a single 1/16 scan panel OR x-coord 0 isn't visable on screen. [#133]

Becomes more obvious a problem when using chaining as well, as rows will be offset by a column:

Or on a single panel, pixel with an x co-ordinate of 0 are not visible (and might show on the last/right column instead)

Solution: Change dma output clock signal phase in your setup configuration. i.e.

mx_config.clkphase = false;

Issue 3: Blurred output [#130] [#75]

https://user-images.githubusercontent.com/60584210/121424145-50dbc680-c971-11eb-94e5-c651e70aa6ea.mp4

Solution: Invert the clock signal in your setup configuration. i.e.

mx_config.clkphase = true;

Note: This is now the default of the library as of 2.0.5.

Issue 4: Flickering or other garbage output [#39] [#35]

Solution:

• Get a better power supply that can supply a stable 5volt output (and no more than 5 volts!).
• Make sure you have capacitors parallel to the HUB75 power input to handle spikes.
• If none of the above helps, it's probably a defective panel.

Issue 5: Color change between panels [#62]

There's batch of craply made panels being sold where the red and green (possibly blue as well) pins have been wrongly wired to another color for the R2/G2 pins.

Solution:

• Change your physical wiring, or change the pin mapping in the library such that red output actually goes to green etc.

Issue 6: Garbled/blurred output on one half of the SAME panel [#130]

https://user-images.githubusercontent.com/60584210/122820652-23313e80-d2dc-11eb-959c-9f40e29f135b.mp4

Solution:

• No solution. You've bought a crap panel.
• Request a refund from the seller.

Issue 7: Some rows are not showing for no reason [#245]

Solution:

• Check the GPIO voltage from the ESP32 when 'HIGH' should be 3.3 volts. If less, then it's a defective ESP32.

Note: These HUB75 panels are supposed to be driven with 5v on the inputs, but they work by accident with 3.3v

Issue 8: Poor WiFi performance when ESP32 is connected to HUB75 panel

This is an electrical noise issue that is out of the control of this library.

Refer to this discussion post on possible solutions: https://github.com/mrcodetastic/ESP32-HUB75-MatrixPanel-DMA/discussions/656#discussioncomment-10435886

Perhaps just buy a WF1 and configure the library as required: https://github.com/mrcodetastic/HD-WF1-LED-MatrixPanel-DMA

[witnessmenow]

Hey

I had a similar issue as "Issue 2" but with a 64x64 (so I presume a 1/32 scan), but it seemed to be impacting the entire display and was shifting what should have been at x=0 to x=63

setting mxconfig.clkphase = false; worked though:

[marcomilazzo]

HI i changhed mx_config.clkphase = true; and i get this . with false i don't get anyrhing any suggestions? thank's marco

[mrcodetastic]

You're panel must be some weird scan type. Try using the 1/8 scan example?

The clkphase setting is a physical electrical configuration thing. So the fact you now get an output = correct value.