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RGB Matrix top half has blue tint
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RGB Matrix top half has blue tint

by ryphez on Fri Apr 30, 2021 5:22 pm

Hi,

I recently picked up the 64x32 RGB LED Matrix - 4mm pitch along with the Bonnet to attach to my Raspberry Pi 3. I have both the Pi and RGB Matrix powered, but when I run the MLB-LED-Scoreboard project (https://github.com/MLB-LED-Scoreboard/m ... board/wiki) the top half of the screen has an overly blue tint. I have linked a picture and have tried reattaching the cables and connections to make sure they're connected.

Image

ryphez
 
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Re: RGB Matrix top half has blue tint

by adafruit_support_mike on Sat May 01, 2021 10:47 pm

Run `raspi-config` and check the overclock settings.

Overclocked CPUs can produce that kind of error.

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Re: RGB Matrix top half has blue tint

by ryphez on Sun May 02, 2021 9:01 pm

The raspbian install was a new install with no modified settings. I checked and the overclock setting is off

ryphez
 
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Re: RGB Matrix top half has blue tint

by adafruit_support_mike on Mon May 03, 2021 10:02 pm

Hmm.. it looks like you're using code that isn't based on the Hzeller module.

The behavior you're seeing is the result of desynchronization between the data, clock, and latch signals. A quick skim through the documentation for the code listed above shows some options to control the signal timing:

Code: Select all | TOGGLE FULL SIZE
--led-pwm-lsb-nanosecond  Base time-unit for the on-time in the lowest significant bit in nanoseconds. (Default: 130)
--led-show-refresh        Shows the current refresh rate of the LED panel.
--led-slowdown-gpio       Slow down writing to GPIO. Range: 0..4. (Default: 1)
Try adjusting those.

The fundamental problem is that the signal to control the blue LEDs don't have time to settle before the clock signal changes. It isn't consistent, so the LEDs only light up occasionally. You'll need to adjust the timing to prevent that.

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Re: RGB Matrix top half has blue tint

by ryphez on Tue May 04, 2021 1:43 pm

Is there anything I can install/run just to test the board displays the right coloring to rule out a board issue?

ryphez
 
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Re: RGB Matrix top half has blue tint

by ryphez on Tue May 04, 2021 2:04 pm

While I was attempting to try the bonnet + matrix on another Raspberry Pi, I ended up re-seating everything and it works as intended. Thanks for the help on this!

ryphez
 
Posts: 4
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Re: RGB Matrix top half has blue tint

by adafruit_support_mike on Wed May 05, 2021 11:20 pm

Glad to hear you got things working. Happy hacking!

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Please be positive and constructive with your questions and comments.