FastLED Platform: Teensy 3.x (K20)

Teensy 3.0/3.1/3.2 support (MK20DX family).

Files (quick pass)

• fastled_arm_k20.h: Aggregator; includes pin/SPI/clockless and helper controllers.
• fastpin_arm_k20.h: Pin helpers.
• fastspi_arm_k20.h: SPI output backend.
• clockless_arm_k20.h: Single-lane clockless driver using DWT cycle counter.
• clockless_block_arm_k20.h: Block/multi-lane variant.
• octows2811_controller.h: OctoWS2811 parallel output integration.
• ws2812serial_controller.h: UART-style serial WS2812 controller.
• smartmatrix_t3.h: SmartMatrix support for Teensy 3.x.
• led_sysdefs_arm_k20.h: System defines for Teensy 3.x.

Notes:

• DWT cycle counter is used for precise timing; interrupt windows are checked to punt frames when overrun.
• Consider FASTLED_ALLOW_INTERRUPTS=1 for responsiveness; long ISRs risk jitter and retries.

Optional feature defines

• FASTLED_USE_PROGMEM: Default 1 on some Teensy3 cores.
• FASTLED_ALLOW_INTERRUPTS: Default 1. Enables FASTLED_ACCURATE_CLOCK.

Place defines before including FastLED.h.