Add NXP LPC8xx (LPC845, LPC804) PlatformIO envs #13

Problem

FastLED now ships first-class support for NXP's LPC8xx Cortex-M0+ family (specifically the LPC845 and LPC804), but PlatformIO-Starter has no envs targeting those parts. Anyone wanting to drive WS2812/APA102 strips from a sub-$2 ARM micro has to figure out the platform package, the per-board IDs, and the chip-specific build flags themselves — and the platform package isn't even in the PlatformIO upstream registry.

What FastLED actually supports (as of master, 2026-06-20)

From src/platforms/arm/lpc/is_lpc.h:

Driver model:

• WS2812-class clockless: bit-banged via clockless_arm_lpc.h (uses the M0 C implementation m0clockless_c.h).
• LPC845-specific fast path: clockless_arm_lpc_pwm_dma.h — SCT + 3-channel DMA-to-GPIO, opt-in with -DFASTLED_LPC_PWM_DMA=1.
• LPC804-specific fast path: clockless_arm_lpc_plu.h — uses the Programmable Logic Unit (26-LUT fabric) because the part only runs at 15 MHz; opt-in with -DFASTLED_LPC_PLU.
• Clocked (APA102/SK9822/WS2801): hardware SPI via spi_arm_lpc.h.

The broader LPC8xx parts the user might assume work (LPC810/811/812/822/824/844/83x/834x) are NOT supported. Only LPC845 and LPC804.

What to add

Mirror the five lpc* envs from FastLED's own platformio.ini (https://raw.githubusercontent.com/FastLED/FastLED/master/platformio.ini), stripping FastLED-internal flags (FASTLED_AUTORESEARCH_*) that don't belong in a starter:

[env:lpc845brk]
; NXP LPC845-BRK breakout — recommended starting point for LPC845.
; Includes the FASTLED_LPC_PWM_DMA fast path (SCT + DMA-to-GPIO).
platform = https://github.com/zackees/platform-nxplpc-arduino.git#2ee527ae80de98e9105329a7260edb003289dfda
board = lpc845brk
framework = arduino
build_flags =
    -DFASTLED_LPC_PWM_DMA=1
lib_deps = FastLED

[env:lpc845]
; Bare LPC845M301 — no dev-kit-specific pin mapping.
platform = https://github.com/zackees/platform-nxplpc-arduino.git#2ee527ae80de98e9105329a7260edb003289dfda
board = lpc845
framework = arduino
lib_deps = FastLED

[env:lpcxpresso845max]
; LPCXpresso845MAX development board.
platform = https://github.com/zackees/platform-nxplpc-arduino.git#2ee527ae80de98e9105329a7260edb003289dfda
board = lpcxpresso845max
framework = arduino
lib_deps = FastLED

[env:lpc804]
; Bare LPC804M101. 15 MHz core — bit-bang clockless does NOT meet WS2812
; timing; opt in to the PLU (Programmable Logic Unit) fast path with
; -DFASTLED_LPC_PLU if you intend to drive WS2812-class LEDs.
platform = https://github.com/zackees/platform-nxplpc-arduino.git#2ee527ae80de98e9105329a7260edb003289dfda
board = lpc804
framework = arduino
lib_deps = FastLED

[env:lpcxpresso804]
; LPCXpresso804 development board. Same 15 MHz caveat as [env:lpc804].
platform = https://github.com/zackees/platform-nxplpc-arduino.git#2ee527ae80de98e9105329a7260edb003289dfda
board = lpcxpresso804
framework = arduino
lib_deps = FastLED

Each as a separate file under platforms/ to match the existing convention.

Quirks worth calling out in the env comments

• Non-registry platform. The upstream platformio/platform-nxplpc package has no LPC8xx boards and no Arduino framework. We use the zackees/platform-nxplpc-arduino fork, which adds the Arduino framework binding via ArduinoCore-LPC8xx. Pin to the exact SHA FastLED uses to avoid surprises.
• Tiny memory. LPC845 = 16 KB SRAM / 64 KB Flash. LPC804 = 4 KB SRAM / 32 KB Flash. FastLED has shipped explicit size-reduction work for these parts; expect tight fits.
• LPC804 timing. At 15 MHz the bit-bang clockless driver cannot meet WS2812 timing. Comment in the env should point users at -DFASTLED_LPC_PLU.

Boards explicitly NOT to add (yet)

• LPC11U24/U35 (FL_IS_ARM_LPC_11_USB), LPC15xx (FL_IS_ARM_LPC_15), LPC11 legacy (FL_IS_ARM_LPC_11_LEGACY). These are supported by FastLED's arm/lpc/ platform tree, but they're outside the LPC8xx scope of this issue — file a follow-up issue if/when wanted.
• LPC810/811/812/822/824/844/83x/834x. Not supported by FastLED; do NOT add envs.

Refs

• FastLED LPC platform tree: src/platforms/arm/lpc/ (is_lpc.h, clockless_arm_lpc.h, clockless_arm_lpc_pwm_dma.h, clockless_arm_lpc_plu.h, led_sysdefs_arm_lpc.h, README.md)
• FastLED platformio.ini reference envs: https://raw.githubusercontent.com/FastLED/FastLED/master/platformio.ini
• Platform fork: https://github.com/zackees/platform-nxplpc-arduino (pinned SHA 2ee527ae80de98e9105329a7260edb003289dfda)
• Upstream platformio/platform-nxplpc: https://registry.platformio.org/platforms/platformio/nxplpc — LPC8xx and Arduino NOT included, do not point users here

Filed via Claude Code research; the platform SHA and per-board IDs above were copied verbatim from FastLED master at the time of writing. Edit on GitHub if any of those defaults need adjusting before implementation.