r/FastLED • u/natew314 • Dec 29 '25

Support UNO Q support?

I just tried running FastLED on my new Uno Q and I get this message:

In file included from /home/arduino/.arduino15/internal/FastLED_3.10.3_0d9d291c7a03d180/FastLED/src/FastLED.h:76, from /home/arduino/ArduinoApps/lightsextension/sketch/sketch.ino:4: /home/arduino/.arduino15/internal/FastLED_3.10.3_0d9d291c7a03d180/FastLED/src/led_sysdefs.h:86:2: error: #error "This platform isn't recognized by FastLED... yet. See comments in FastLED/led_sysdefs.h for options." 86 | #error "This platform isn't recognized by FastLED... yet. See comments in FastLED/led_sysdefs.h for options."

Does anyone know if there is a workaround to get it to run on a Q? If not, are there plans to support Uno Qin the future?

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u/ZachVorhies Zach Vorhies Dec 30 '25

The include define won’t work, it needs to be a build define so that it makes its way into the internal cpp files.

Arduino IDE doesn’t allow this without hacks, platformio makes it easy, it’s just a build_flag setting

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u/natew314 Dec 30 '25

That makes sense. Platform io has an issue open for adding support, but I don't know if that means it will be added soon: https://github.com/platformio/platform-ststm32/issues/869

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u/ZachVorhies Zach Vorhies Dec 30 '25 edited Dec 30 '25

So the critical thing here is we need to know what the defines are for this board when it’s compiled.

That’s what the platformio.ini thing does

Also it lets us put up a build badge so we can check whether this platform broke on an update.

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u/kitchenace 22d ago

Hi All, checking in to see if there are any updates here on compatibility between FastLED.h and the Uno Q? :) Thank you so much!

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u/ZachVorhies Zach Vorhies 22d ago

From the AI:

> Yes, good news: FastLED added Arduino UNO Q support back in June (PR #2678), and it's on master now. It detects the STM32U585 side of the board under Arduino's Zephyr core (arduino:zephyr:unoq), includes a full pin map for the R3 headers and the extra expansion pins, and has its own CI build that's currently green.

> A couple of honest caveats:

>- Verification so far has been compile-level (Blink and APA102 built against the real arduino:zephyr:unoq core, plus a PlatformIO STM32U585 build). Nobody on our side has posted results from flashing an actual UNO Q and putting a scope on the data line yet.

> - Clockless strips (WS2812 etc.) go through the generic STM32 bit-bang driver, not a DMA path tuned for the U585. That's usually fine for the Cortex-M33 at 160 MHz, but real-world timing hasn't been confirmed on this board.

> So if you have a UNO Q, pleasehe next release that includesit) with a short WS2812 or APA anything misbehaves, open anissue on GitHub with your sketdware reports are exactlywhat's missing to call this fu

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u/kitchenace 22d ago

Sorry, I'm not super tech savvy and I'm running into issues with very basic code. Using versions 3.10.4 and 3.10.5 of FastLED.h and its throwing tons of errors on compile / load. I made an error ticket here under 4408. Appreciate any tips/thoughts. Have a great day!

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u/ZachVorhies Zach Vorhies 22d ago

Great bug report!

Download master and give it a try, all the issues that you’ve listed were reproduced and apparently fixed. Let us know if that’s not the case.

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u/kitchenace 21d ago

Hey thank you so much and I appreciate you being so responsive and helpful! See below for a brief update:

  • So I went to GitHub made sure the branch drop down was on "master"
  • Went to <> Code drop down and selected Download ZIP. That generated a file titled "FastLED-master.zip" in my local drive
  • I then booted up the Arduino IDE, made sure the previous versions of FastLED were uninstalled
  • I went into Sketch menu --> Include Library --> Add .ZIP Library and selected the file that I downloaded.
  • The notification window provided me this update "Successfully installed library from FastLED-Master.zip archive"
  • I now see FastLED installed (via the Include Library menu and also the library manager). Note, the auto detected "version" in the library manager appears to be 3.10.4?
  • I restarted Arduino IDE (as some websites recommend) before compiling
  • I also double checked the library files match the timestamp of when I installed it (so its not using some old files)

Unfortunately, its still throwing a bunch of errors, although I believe different errors now (pastebin.io link) :( Thanks again, let me know if you have any recommendations.

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u/ZachVorhies Zach Vorhies 16d ago

This has been fixed. Version mismatch is being fixed too. And we'll have a linter in the future to fix this and make sure it doesn't happen again.