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Drive an RGB matrix with ItsyBitsy m0 express?
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Drive an RGB matrix with ItsyBitsy m0 express?

by bullerd on Mon Apr 15, 2019 10:48 am

I have 2 ItsyBitsy m0 expresses on order, and was wondering if it would be possible to use them to drive a 32x32 RGB matrix using either Arduino or Circuit Python code. I've already got the setup to connect the RGB panel to a Pi (using the Matrix Pi Hat for the RPi and a wiring harness for an Arduino). And, if it is possible to control the RGB matrix from the ItsyBitsy, is it possible to load the Python libraries so that I can use Circuit Python to control it? I would like to use the device in a classroom where the students are learning Python, so that's my preferred solution.

Thanks for the great products and support!

-David

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Re: Drive an RGB matrix with ItsyBitsy m0 express?

by bcochran1 on Mon Apr 15, 2019 10:15 pm

Hi!

Speaking just for myself, as another customer, I'm Neopixel crazy and the ItsyBitsy devices run them just fine. They are more powerful than ordinary Arduino devices: faster clock speeds and more memory. I'm a little frustrated that they don't have a lot of QSPI flash, but they sure can drive pixels.

Please note that I have not really graduated yet to CircuitPython. All my NeoPixel code is in Arduino. I just take the "strand test" example and modify it slightly to account for my particular Pixel count, and also to have it use pin #5. Why that pin? Because it level shifts the signals to 5v logic. I have also been playing with using DMA to drive the pixels. Click on the photo I've attached so you can see the neopixel strip.

Thanks so much,

Bob

two_itsy_bitsy_projects_with_neopixels_small.jpg
two_itsy_bitsy_projects_with_neopixels_small.jpg (192.68 KiB) Viewed 55 times



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Re: Drive an RGB matrix with ItsyBitsy m0 express?

by bullerd on Tue Apr 16, 2019 12:51 am

Hi Bob,

Thanks for the info, especially the point about pin#5 sending 5V logic...I hadn't seen that in the specs!

I agree with you that LED strips are a lot of fun and have great support in CircuitPython. My strip of choice is the Dotstar, and I've had good luck getting them to work with Raspberry Pi, micro:bit, and Circuit Playground Express, so I'm fairly sure I'll get them working with the ItsyBitsy. The RGB matrix/panel is another story; while I've gotten it working with an Arduino and a Raspberry Pi, I haven't seen any information about getting it to work with Python on anything other than the Pi.

Thanks again for the info, and taking the time to help.

bullerd
 
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Re: Drive an RGB matrix with ItsyBitsy m0 express?

by adafruit_support_carter on Tue Apr 16, 2019 3:27 pm

Arduino for sure. The library is here:
https://github.com/adafruit/RGB-matrix-Panel
and the main guide is here:
https://learn.adafruit.com/32x16-32x32- ... x/overview
but there's also this guide:
https://learn.adafruit.com/rgb-matrix-f ... g/overview

There's no CircuitPython support yet. The matrix panels have a tight timing requirement and CP would need to have a low level helper library written. Similar to NeoPixel:
https://circuitpython.readthedocs.io/en ... ixel_write
and DotStar (which relies on SPI).

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Re: Drive an RGB matrix with ItsyBitsy m0 express?

by bcochran1 on Tue Apr 16, 2019 7:33 pm

@bullerd, please take the time to read the "Neopixel Uber Guide" from start to finish, and pay special attention to the sections on powering the pixels. If I have any more than about 12 pixels in a ring, I power them with a separate 5v 10A supply. I don't expect my ItsyBitsy device to source the power and I refuse to try and get my much more expensive laptop to source the power over USB, either. Pixels (and Dotstars) need plenty of amps to run.

Thanks so much

Bob

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Re: Drive an RGB matrix with ItsyBitsy m0 express?

by bullerd on Wed Apr 17, 2019 8:44 pm

Thanks for the replies; will definitely try the Arduino library.

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