decode_ws2812.h File Reference

Detailed Description

Shared 4-phase WS2812 edge-pair -> byte decoder (declaration).

Lifted out of the duplicated bodies in platforms/shared/rx_device_native.cpp.hpp::NativeRxDevice::decode and platforms/arm/lpc/rx_sct_capture.cpp.hpp::LpcSctRxChannel::decode – both were verbatim copies of the same algorithm. The per-driver decode() wrappers keep their device-specific FL_WARN messages (which reference the pin number; this function does not know about it).

Scope. This decoder handles the variant used by Native and LPC SCT – reset-pulse breakout when LOW exceeds reset_min_us, gap-tolerance fallback when gap_tolerance_ns > 0, 10 %-error gate against the number of bits actually decoded. The FlexPWM (decodeEdges in rx_flexpwm_channel.cpp.hpp) and FlexIO (decodeEdgesFlexIo in rx_flexio_channel.cpp.hpp) drivers use a slightly different variant (partial-byte left-shift, no reset detection, no gap tolerance, different error counting). Folding those into this function is a separate change tracked under FastLED #3035 Phase 3 – see the issue for the rationale and the behaviour deltas.

Preserved-from-original quirks (intentionally NOT fixed in the consolidation, see #3035 follow-ups):

1. Reset-pulse detection fires BEFORE gap-tolerance evaluation, so a LOW pulse in the documented "reset_min_us .. gap_tolerance_ns" window currently terminates the frame instead of being tolerated. Matches the prior behaviour of both Native and LPC decoders.
2. Error-rate denominator is bytes_written * 8 rather than total decoded bits; the partial trailing bit_index residue is not counted. Can over-reject frames that end mid-byte. Same preserved behaviour.

Definition in file decode_ws2812.h.

#include "fl/channels/rx.h"
#include "fl/stl/noexcept.h"
#include "fl/stl/result.h"
#include "fl/stl/span.h"
#include "fl/stl/stdint.h"

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Namespaces
namespace	fl
	Base definition for an LED controller.
namespace	fl::channels
namespace	fl::channels::rx

Functions
fl::result< u32, DecodeError >	fl::channels::rx::decodeWs2812Edges (const ChipsetTiming4Phase &timing, fl::span< const EdgeTime > edges, fl::span< u8 > out) FL_NOEXCEPT
	Decode a WS2812 edge-pair stream into bytes.