pdmini_codec.c File Reference

The PD mini's codec: the CRC8 (cyclic redundancy check, 8 bits) of a frame and the framing of a reply. More...

#include "pdmini.h"

Functions
uint8_t	pdmini_crc8 (const uint8_t *p, size_t n)
	CRC8, polynomial 0x31, initial 0xFF, over n bytes.
static size_t	fixed_len (uint8_t cmd)
	A fixed-length reply's whole length, or 0 for one that is not.
pdmini_frame_t	pdmini_reply_frame (uint8_t cmd, const uint8_t *buf, size_t n)
	Checks the bytes received so far against a reply to cmd.

Detailed Description

The PD mini's codec: the CRC8 (cyclic redundancy check, 8 bits) of a frame and the framing of a reply.

See pdmini.h.

SPDX-License-Identifier: MIT

Function Documentation

fixed_len()

size_t fixed_len ( uint8_t cmd )

static

A fixed-length reply's whole length, or 0 for one that is not.

Parameters

cmd	Command byte the reply answers.

Returns

The reply length in bytes, or 0 for a command whose reply is not fixed in length.

pdmini_crc8()

uint8_t pdmini_crc8	(	const uint8_t *	p,
		size_t	n )

CRC8, polynomial 0x31, initial 0xFF, over n bytes.

Parameters

p	Bytes to check.
n	Number of bytes in p.

Returns

The CRC8 of the bytes.

pdmini_reply_frame()

pdmini_frame_t pdmini_reply_frame	(	uint8_t	cmd,
		const uint8_t *	buf,
		size_t	n )

Checks the bytes received so far against a reply to cmd.

Parameters

cmd	Command byte the reply answers.
buf	Bytes received so far.
n	Number of bytes in buf.

Returns

PDMINI_MORE, PDMINI_DONE or PDMINI_BAD.