FastLED — monthly activity digest

What landed on FastLED's main branch, month by month. External-context reference (like the v1/v2/MoonLight inventories) — a factual log of a friend repo's releases, not projectMM's own history or roadmap. Newest month on top. The reusable prompt that generates these digests lives in README.md.

August 2026

No release cut this month (3.10.4, 2026-06-16, remains the published release, with the 3.10.5 tag on master unreleased), so the month is not split. Three threads dominate: filling in long-standing chipset and board gaps from very old issues, bringing the Raspberry Pi Pico 2 W online with WiFi and Bluetooth, and replacing the MP3 decoder.

New - On-chip flash storage works at last: sketches can read and write files on an ESP32 without an SD card, through a new fl::getEmbeddedFs(). - Raspberry Pi Pico 2 W gains WiFi (CYW43) and Bluetooth LE, plus a device-to-device over-the-air update flow. - ESP32 sketches can now pick which SPI bus (SPI2 or SPI3) each strip uses, so two clocked strips can run on separate buses. - New chipsets: WS2818, LC8816E (RGBW), MY9221 (12-channel, as used on Grove chainable RGB modules), TM1812 in five-channel RGBWW mode, and HD107S as an alias. - New platforms: Chipintelli CI13XX (RISC-V), and Teknic ClearCore / SAME53 boards. - Non-addressable analog RGB LEDs get a real driver: addLeds<ANALOG, RED_PIN, GREEN_PIN, BLUE_PIN>() with 500 Hz PWM, and brightness, color correction, and temperature applied like any other strip. - Optional Oklab color blending (fl::blend_oklab) for smoother, more natural-looking fades than plain channel blending. - Pixel buffers can be saved and loaded as JSON, with a worked ESP32 flash-storage example. - ESP8266 sketches can override the clockless wait time with FASTLED_ESP8266_CLOCKLESS_WAIT_TIME. - The MoodRing example is split out on its own and reworked so kick, snare, and downbeat each do something visually distinct instead of all just changing speed. - MP3 playback switches to the minimp3 decoder and now decodes in fixed point by default, which is faster on chips without a floating-point unit. The old Helix decoder is gone, along with its license restrictions.

Fixed - FastLED.clear() and clearData() only cleared the first strip of a parallel controller, which also made power limiting under-count. Open since 2020. - rgb2hsv_approximate() no longer overflows and returns wrong hues on some colors. Open since 2020. - ESP32: software SPI clock toggling no longer stomps on other pins changing at the same time. - ESP32: strip reset timing now follows each chipset's own datasheet value rather than a fixed one. - ESP32: selecting the legacy RMT4 backend on ESP-IDF 5 now gives one clear error instead of a build failure, and C2/C3/S2 fall back to bit-bang for clocked chipsets instead of failing. - ESP8266: Arduino D0-D8 pin constants are no longer remapped twice, and example default pins moved off pins that conflict with serial. - SAMD51 builds, broken since 3.10.4, compile again; SAMD boards use native SERCOM for hardware SPI; the Adafruit QT Py M0 onboard NeoPixel pin and the Metro M4 board alias are recognized. - Seeed XIAO nRF52840 Plus/Sense Plus builds work under the Mbed core. - Teensy: builds fixed across the range (3.x F_CPU_ACTUAL, Teensy 4 SD card SPI, parallel output line masks), and Teensy 3.x/LC now emit a warning that the hardware is end-of-life and unvalidated. - AVR: ATmega644A hardware SPI pins added, and examples no longer default to the serial TX pin. - FastLED.wait() with no arguments now waits until output actually finishes instead of timing out early. - Video playback no longer crashes on zero-sized frames. - GS1903 strips get their own timing instead of borrowing WS2812's. - Browser/WASM preview: asset loading is bounded and verified, so a stalled download no longer hangs the sketch forever.

Watching - A proposed license change from MIT to a new "FastLED Reciprocal License 1.0" is under discussion (#4046, #4047, #4048). Nothing has changed yet: master is still MIT. Under the proposal, shipping a product with modified FastLED would require publishing those modifications. - A large "profiled color pipeline" design is being planned in ten tracked phases (#4032 through #4044), aiming at datasheet-accurate color, gamut mapping, and float-free fixed-point output. - The open report that show()'s refresh throttle takes an unconditional deep yield (#3762) is still unresolved.

Auditability: 195 first-parent commits on master with author-date 2026-08-01..2026-08-31, via git log --first-parent --since=2026-08-01 --until=2026-09-01 origin/master. Issues via gh api "search/issues?q=repo:FastLED/FastLED+is:issue+created:2026-08-01..2026-08-31&per_page=100" (102 opened) and the same with closed:2026-08-01..2026-08-31 (187 closed). The great majority of both are the project's own phase, meta, and CI trackers, so only user-facing ones are surfaced above. No versioned release was published in August (latest published release remains 3.10.4 from June; the 3.10.5 tag is an ancestor of master but has no GitHub release), so no month split.

July 2026

No release cut this month (3.10.4, 2026-06-16, remains the latest), so the month is not split. Two big threads: finishing the Raspberry Pi Pico driver family, and cutting the ESP32 platform loose from the Arduino core.

New - Raspberry Pi Pico / RP2040: automatic parallel PIO output finally works for real — 2/4/8 strips driven from one PIO program, with a single-lane fallback for mixed layouts. - Raspberry Pi Pico gains fixed-function SPI+DMA drivers, a UART DMA driver, and a public hardware-SPI routing API. - WS2814 RGBW strips are now a first-class chipset with datasheet timing. - Classic ESP32 gains a second I2S bank — up to 32 parallel strip outputs — plus a second UART output lane. - FastLED can be built as a plain ESP-IDF project with no Arduino core at all: IDF's own time, serial, SPI, LEDC and heap calls are now the default on ESP32, with Arduino only as an opt-in fallback. - Classic ESP32 also gains an I2S-based signal capture backend (reading WS2812 data in), alongside the existing RMT and LPC845 capture paths. - LPC845 now defaults to its UART DMA output path. - Screenmaps can describe EL wire and EL panel shapes; a new HydroPack example drives two EL panels from a microphone beat detector. - fl::printf/snprintf accept a generic {} placeholder.

Fixed - ESP8266: addLeds() no longer watchdog-resets when GPIO12 (D6) is used with P9813. - rgb2hsv_approximate() no longer turns orange into green; CHSV values now compare by field instead of by their RGB rendering. - TM1829 timing (FLIP + wait time) restored after a refactor dropped it. - SK9822/APA102 on the classic addLeds path now emit correct all-ones end clocks. - ESP32 I2S clock divider no longer silently truncates, which could produce wrong strip timing. - m0clockless brightness scaling was broken and always output zero. - Teensy 4.x SPI drivers no longer depend on the Arduino SPI library; Renesas boards no longer pull in an I2S header they don't have. - WASM/browser preview: microphone capture recovers after the user cancels access, and the default renderer works again.

Watching - Report that RGBW output has been broken since 3.10.3 (#3622, closed) fed the month's RGBW colorimetry cleanups. - An open thread (#3762) blames an unconditional deep yield in show()'s refresh throttle for a long-standing frame-timing regression — no fix shipped yet. - A port to the WCH CH32V003 (48 MHz, 2 KB RAM) is proposed (#3755).

Auditability: 212 first-parent commits on master with author-date 2026-07-01..2026-07-31. Issues via search/issues for repo:FastLED/FastLED+is:issue+created:2026-07-01..2026-07-31 (110 opened) and closed:2026-07-01..2026-07-31 (106 closed); the great majority are the project's own phase/meta bring-up trackers for RP2040, LPC845 and the classic-ESP32 I2S driver, plus CI and linter work — only the user-facing ones are surfaced above. No versioned release published in July, so no month split.

June 2026 (up to 3.10.4)

Released 3.10.4 (2026-06-16), cut from master.

New - STM32: Arduino UNO Q board support. - New NXP LPC8xx family drivers land (LPC804 PLU, LPC845 bit-bang + PWM/DMA-to-GPIO, LPC11xx) — early bring-up, bench-validated. - Unified fl::Watchdog API with real hardware implementations across platforms (ESP32, Teensy 4, AVR, Apollo3, RP2040, STM32) plus a non-allocating reset/crash-classification helper. - Wave simulation: opt-in 9-point isotropic Laplacian (smoother 2D waves), exposed as a UI toggle in several example sketches. - ScreenMap gains a v2 schema (auto-detected), and a new .fled container format for video/screenmaps that FxSdCard can load. - FFT now auto-detects ESP-DSP on ESP32 (no opt-in macro needed).

Fixed - RGBW colorimetric path reworked: native LED gamut + D65 as the default source, improved strict/boosted solvers, corrected dual- and 3-channel solving. - ESP32: reliable streaming for SPI strips over ~680 LEDs; ESP32-C6 routes Serial to HWCDC with non-blocking writes and rejects USB-serial pins for LED output. - Teensy Audio selection fixed on low-memory boards; nRF52 now honors configured SPI data rates. - LuminescentGrand example: corrected serpentine column wiring/orientation.

June 2026 (post-3.10.4)

New - Teensy 4.x LED driver bring-up: ObjectFLED and FlexIO parallel output engines plus a new LPUART-based WS2812 driver (inverted-TX + eDMA), and FlexPWM-based RX capture. - New WS2812-style RX capture path on classic ESP32 (RMT4) and LPC845 (SCT+DMA). - ARM Cortex-M DSP-extension SIMD backend wired up for Teensy 3.x/4.x (faster scale/blend on those chips).

Fixed - SM16824E chipset timing corrected to match the datasheet. - RGBW gamut configuration is now kept per strip. - Fixed a memory leak in the chunked fl::deque container.

Note: the bulk of June's ~481 commits were internal (LPC bring-up scaffolding, the AutoResearch hardware-test harness, a Python→Rust C++ linter migration, RPC/JSON size-and-speed tuning, and test-file splits) and are not user-visible. Notable issue traffic was dominated by the Teensy driver and LPC845 bring-up trackers; a user-reported "multi strip problem" (#3340) was triaged and closed, and a deque refactor briefly broke a macOS-arm64 audio unit test (#3286, fixed same month).

Auditability: 481 commits with author-date in 2026-06-01..2026-06-30 on master (first-parent/merged view); split at the 3.10.4 release (published 2026-06-16, an ancestor of master). Issues reviewed via search/issues for created:2026-06-01..2026-06-30 and closed:2026-06-01..2026-06-30 (~50 each); user-facing ones folded in above, the remainder were internal bring-up/CI/linter trackers.

May 2026

Summarised from 150 first-parent commits on master, 2026-05-01 … 2026-05-31.

New

• New Channels API for managing multiple LED drivers at once — a fl::Bus type, FastLED.add<Bus>(...), fl::enableAllDrivers(), and FastLED.setExclusiveDriver(...), with a diagnostic that warns when a strip's driver doesn't match its bus. (The month's biggest effort.)
• RGBW / RGBWW color: proper colorimetric RGB→RGBW conversion with a lookup table, color-temperature (CCT) control, and an RGB+CCT mode.
• ESP32-P4 gains a SIMD (PIE) acceleration backend for faster pixel processing.

Faster

• Big speedups to the ESP32-P4 PARLIO parallel driver — encoding and transmission now overlap, and a chipset-aware encode path is ~5× faster than before.
• ESP32-P4 "Wave8" output ~1.2–2× faster via new transpose and lookup-table paths.

Hardware & build

• Builds cleanly on ESP-IDF 6, and can now be used as a standalone ESP-IDF component.
• ESP32 OTA support fixed (adds the required update/mDNS dependencies).
• Fixes for several boards: nRF52 Xiao BLE Sense and other nRF52 variants, ESP8266 / STM32 / ESP32-C3 / Teensy 4 / UNO R4 WiFi build issues, and ESP32-S3 LCD-clockless ISR safety.

Fixed

• RGBW driver no longer kept a dangling pointer to its color profile (could crash or corrupt output).
• AVR boards no longer try to compile RGBWW examples that overflow their memory.

April 2026

Summarised from 237 first-parent commits on master, 2026-04-01 … 2026-04-30.

New

• Audio "silence gate" across the audio-reactive features — tempo, spectral metrics, and the Vibe effect now fade out cleanly when the input goes quiet instead of reacting to noise.
• Audio FFT can run on the ESP-DSP hardware backend (faster spectrum analysis on ESP32).
• ESP32-S3 LCD driver gains ISR-driven chunked DMA output (smoother large-strip output); coroutine tasks can be pinned to a chosen core.
• RMT receive (reading signals in) gains DMA streaming; a long-strip SPI bug (#2254) fixed.

Fixed

• ESP32-S3 LCD-clockless GPIO crash; SPI bus ownership/buffer-reuse issues when switching drivers.
• Board fixes: Teensy 4.1 pins 40–54, Arduino Due (sam3x8e), ESP8266 register-name clash, Digispark ATtiny85.

March 2026

Summarised from 444 first-parent commits on master, 2026-03-01 … 2026-03-31.

• Mostly an internal stability and build-correctness month (sanitizer fixes, WASM build speed, IWYU/PCH hygiene) — little user-facing.
• Fixed: AVR builds (replaced defaulted noexcept with explicit implementations in container types); ESP32-C3/C5 and Teensy build breakages; printf/Arduino-compatibility shim; an audio-path bug.

February 2026

Summarised from 516 first-parent commits on master, 2026-02-01 … 2026-02-28.

• Fixed (broad platform-stability month): AVR math bugs (left-shifts wider than AVR's 16-bit int; PROGMEM LUT reads), ESP32-C6 dual-mode async/sync SPI, ESP32 WROOM + mbedTLS, ESP8266, Teensy LC, UART compiler issues, RGBW mode, and the UCS chipset preamble.
• HTTP-server / loopback networking pieces stabilised; OTA validation fixed.

January 2026

Summarised from 582 first-parent commits on master, 2026-01-01 … 2026-01-31.

• A heavy stability-hardening month — most of the work was fixing memory and initialization bugs surfaced by sanitizers (ASan/LSan/UBSan): use-after-free, memory leaks, static-initialization-order issues, shared-pointer errors.
• Fixed (user-visible): a crash in power management; RP2350 system defines not being included; an ISR error where an int was read as a bool; i2s/LCD-CAM.

December 2025

Summarised from 392 first-parent commits on master, 2025-12-01 … 2025-12-31.

New

• PARLIO driver maturation (ESP32 parallel output): streaming support, up to 16 lanes, larger per-channel LED counts, background DMA buffer worker, and a low-level hardware abstraction layer — plus many alignment/timing fixes (the "1-bit shift" buffer-boundary bug).
• Validation / proof-of-life framework: hardware-in-the-loop validation, an ESP32 watchdog (with a USB-disconnect fix), and a result banner.
• New Potentiometer class (hysteresis + calibration); 16-bit PWM pin support (setPwm16); per-channel gain on the HD108 chipset; Serial gains printf.
• Signal receive (RX) gains raw edge-time capture and a safe sketch-halt.

November 2025

Summarised from 528 first-parent commits on master, 2025-11-01 … 2025-11-30.

New

• Channels / ChannelBusManager foundation — a unified, priority-based driver manager with fallback, centralized SPI driver registration, and a new ChannelEngine-based SPI driver + RMT4 driver for ESP32 IDF 4.x. (Start of the multi-driver architecture that continues through to May.)
• PARLIO gains a runtime-configurable multi-channel driver with auto-select (and dropped ESP32-S3, which uses LCD instead).
• New UCS7604 controller; a generic clockless waveform generator; video playback support.
• Audio-reactive effects expand — downbeat-darkness effect, AnimartrixRing audio reactivity, configurable UI audio.
• WASM web preview moves to dedicated worker threads (drops Asyncify) with incremental/PCH build speedups.
• Experimental RISC-V interrupt support.

October 2025

Summarised from 1,185 first-parent commits on master, 2025-10-01 … 2025-10-31.

New

• RP2040 automatic parallel output using the standard FastLED API.
• Per-platform ESP32 clockless controllers + configurable ESP32/ESP8266 timing; nanosecond timing support for ARM K66/KL26; SPI chipset controllers split into their own headers.
• Fallback OTA implementation for ESP-IDF < 4.0.
• PARLIO strategic buffer-breaking at color boundaries.
• 8-bit math optimised for ATtiny; math template/float overloads; a beat-detection AudioProcessor facade.
• New "advanced effects" and "LED cookbook" documentation chapters.

September 2025 (post-3.10.3)

Summarised from 162 first-parent commits on master, 2025-09-21 … 2025-09-30 (after the 3.10.3 release on the 20th).

New

• WASM web-preview overhaul — Three.js-based tile rendering, instanced LED rendering, SharedArrayBuffer zero-copy frames, a background-worker async controller, and an improved video recorder (native captureStream, 60 FPS, better MP4 compatibility).
• New hardware-accelerated ezWS2812 GPIO + SPI drivers for Silicon Labs MGM240 / EFR32MG24 (MG24) boards.
• Codec support — progressive JPEG decoding (4 ms time budget), and metadata parsing for GIF/JPEG/MPEG1.
• Bilinear interpolation for upscaling effects; FxNoiseRing low-memory mode.
• README/wiring guidance for high-parallel LED setups (incl. ObjectFLED parallel capacity).