m5::unit::ir::NecCodec Class Reference

NEC / Extended NEC IR protocol encoder/decoder. More...

#include <nec_codec.hpp>

Inheritance diagram for m5::unit::ir::NecCodec:

Public Member Functions
	NecCodec ()
	Constructor.
item_container_type	encode (uint16_t address, uint16_t command, bool repeat) override
	Encode a standard or extended NEC frame, or the 2-item repeat frame when repeat is true.
bool	decode (const gpio::m5_rmt_item_t *items, uint32_t num, DecodeResult &result) override
	Decode a NEC full frame or repeat frame.
uint32_t	carrierFrequencyHz () const override
	Carrier frequency for NEC (38 kHz)
item_container_type	encodeRaw (uint32_t data)
	Encode with explicit 32-bit raw data.
item_container_type	encodeRepeat ()
	Encode NEC repeat code.
Public Member Functions inherited from m5::unit::ir::IRCodec
	IRCodec (CodecType t)
CodecType	type () const
	Get codec type for safe downcasting.
virtual float	carrierDuty () const
	Carrier duty cycle (0.0 - 1.0)
virtual uint8_t	minFrames () const
	Number of frames that should be transmitted per keypress for this protocol.
virtual uint16_t	frameGapUs () const
	Inter-frame gap (microseconds) when transmitting multiple frames in one burst.
virtual bool	decode (const m5::unit::gpio::m5_rmt_item_t *items, uint32_t num, DecodeResult &result)=0
	Try to decode RMT items into an IR command.

Detailed Description

NEC / Extended NEC IR protocol encoder/decoder.

• Carrier: 38 kHz, duty 1/3
• Modulation: Pulse Distance (mark duration constant, space varies)
• Bit order: LSB first
• Standard NEC: 8-bit address + inverted + 8-bit command + inverted = 32 bits
• Extended NEC: 16-bit address (no inversion) + 8-bit command + inverted = 32 bits
• Repeat code: 9ms mark + 2.25ms space + 560us mark

Timing

Element	Mark (us)	Space (us)
Leader	9000	4500
Bit "1"	560	1690
Bit "0"	560	560
Repeat	9000	2250
Stop	560	-

Member Function Documentation

carrierFrequencyHz()

uint32_t m5::unit::ir::NecCodec::carrierFrequencyHz ( ) const

inlineoverridevirtual

Carrier frequency for NEC (38 kHz)

Implements m5::unit::ir::IRCodec.

encode()

item_container_type m5::unit::ir::NecCodec::encode ( uint16_t address, uint16_t command, bool repeat )

overridevirtual

Encode a standard or extended NEC frame, or the 2-item repeat frame when repeat is true.

Implements m5::unit::ir::IRCodec.

encodeRaw()

item_container_type m5::unit::ir::NecCodec::encodeRaw

(

uint32_t

data

)

Encode with explicit 32-bit raw data.

Parameters

data	32-bit NEC frame (address + ~address + command + ~command)

Returns

RMT items

encodeRepeat()

item_container_type m5::unit::ir::NecCodec::encodeRepeat

(

)

Encode NEC repeat code.

Returns

RMT items for repeat frame