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:

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]

Video.2.2.1.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]

assembly.Video.4.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

[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.