fl::spi::Device Class Reference

Detailed Description

Single-channel SPI device interface (TX-only, transaction-based, optimized for FastLED)

Provides easy-to-use API for SPI communication with two levels:

1. Transaction API (writeAsync) - Primary interface, returns Transaction handles
2. Zero-Copy DMA (acquireBuffer/transmit) - Expert API for maximum performance

TX-Only, Transaction-Based Design: This SPI implementation is optimized for LED strip output (WS2812, APA102, SK6812, etc.) and only supports transmission (MOSI). Read operations (MISO) are not supported because:

• LED strips are receive-only devices (no status/readback)
• Removing RX support simplifies hardware configuration
• Allows more efficient DMA and buffer management

Transaction API (Simpler Implementation): All operations use the transaction-based API (writeAsync()) which returns a Transaction handle. This provides a single, consistent interface that's easier to implement and use:

• Async by default, but can be made blocking by calling wait() immediately
• Consistent error handling through Result<Transaction>
• Natural fit for DMA-based hardware

Note

This class uses RAII - hardware is released on destruction

Non-copyable, non-movable (owns hardware resources)

Definition at line 48 of file device.h.

#include <device.h>

Collaboration diagram for fl::spi::Device:

Classes
struct	Impl
	Private implementation data for Device class. More...

Public Member Functions
	Device (const Config &config) FL_NO_EXCEPT
	Construct SPI device with configuration.
	~Device () FL_NO_EXCEPT
	Destructor - releases hardware resources.
DMABuffer	acquireBuffer (size_t size) FL_NO_EXCEPT
	Acquire DMA-capable buffer for zero-copy transmission.
fl::optional< fl::task::Error >	begin () FL_NO_EXCEPT
	Initialize the SPI hardware.
void	end () FL_NO_EXCEPT
	Shutdown the SPI hardware and release resources.
const Config &	getConfig () const FL_NO_EXCEPT
	Get current configuration.
bool	isBusy () const FL_NO_EXCEPT
	Check if async operation is in progress.
bool	isReady () const FL_NO_EXCEPT
	Check if device is initialized and ready for use.
fl::optional< fl::task::Error >	setClockSpeed (u32 speed_hz) FL_NO_EXCEPT
	Update clock speed.
fl::optional< fl::task::Error >	transmit (DMABuffer &buffer, bool async=true) FL_NO_EXCEPT
	Transmit from previously acquired DMA buffer.
bool	waitComplete (u32 timeout_ms=(fl::numeric_limits< u32 >::max)()) FL_NO_EXCEPT
	Wait for pending async operation to complete.
Result< Transaction >	writeAsync (const u8 *data, size_t size) FL_NO_EXCEPT
	Begin asynchronous write operation (returns immediately)

Private Member Functions
	Device (const Device &) FL_NO_EXCEPT=delete
Device &	operator= (const Device &) FL_NO_EXCEPT=delete

Private Attributes
fl::unique_ptr< Impl >	pImpl

Friends
class	Transaction

---

The documentation for this class was generated from the following files:

• fl/channels/spi/device.h
• fl/channels/spi/device.cpp.hpp