Overview

Simple, robust, and efficient serial communication.

Classes
class	pw::hdlc::Frame

class	pw::hdlc::Decoder

class	pw::hdlc::DecoderBuffer< kSizeBytes >
	Declares a buffer along with a `Decoder`. More...

class	pw::hdlc::Encoder
	Encodes and writes HDLC frames. More...

class	pw::hdlc::Router

Functions
Status	pw::hdlc::WriteUIFrame (uint64_t address, ConstByteSpan payload, stream::Writer &writer)
	Writes an HDLC unnumbered information frame (UI frame) to the provided `pw::stream` writer.

constexpr	pw::hdlc::Encoder::Encoder (stream::Writer &output)
	Constructs an encoder which will write data to `output`.

Status	pw::hdlc::Encoder::StartUnnumberedFrame (uint64_t address)

Status	pw::hdlc::Encoder::WriteData (ConstByteSpan data)

Status	pw::hdlc::Encoder::FinishFrame ()
	Finishes a frame. Writes the frame check sequence and a terminating flag.

Function Documentation

Status pw::hdlc::Encoder::StartUnnumberedFrame ( uint64_t address )

inline

Writes the header for a U-frame. After successfully calling StartUnnumberedFrame(), WriteData() may be called any number of times.

Status pw::hdlc::Encoder::WriteData ( ConstByteSpan data )

Writes data for an ongoing frame. Must only be called after a successful StartInformationFrame() call, and prior to a FinishFrame() call.

Writes an HDLC unnumbered information frame (UI frame) to the provided pw::stream writer.

This function is a convenience alias for the more general Encoder type and set of functions.

Parameters

address	The frame address.
payload	The frame data to encode.
writer	The `pw::stream` to write the frame to. The frame contains the following bytes. See Design for more information. HDLC flag byte (`0x7e`) Address (variable length, up to 10 bytes) UI-frame control (metadata) byte Payload (0 or more bytes) Frame check sequence (CRC-32, 4 bytes) HDLC flag byte (`0x7e`)

Returns

OK: The write finished successfully.
RESOURCE_EXHAUSTED: The write failed because the size of the frame would be larger than the writer's conservative limit.
INVALID_ARGUMENT: The start of the write failed. Check for problems in your address argument's value.