arrow-firmware/components/aprs/include/aprs_decoder.h

/*
 * aprs_decoder.h
 *
 *  Created on: Sep 1, 2019
 *      Author: curiousmuch
 */

#ifndef APRS_DECODER_H_
#define APRS_DECODER_H_

#include <stdio.h>
#include <stdint.h>

//#define uint8_t unsigned int
//#define uint32_t unsigned int

/* Constants and Defines */
#define APRS_MAX_FRAME 256

/* Data Structures */

typedef enum {
	NORMAL,
	FRAME_DECODED,
	ERROR_FCS_MISMATCH,
	ERROR_PACKET_FORMAT,
	ERROR_BUFFER_OVERFLOW
} decoder_output_t;

typedef enum {
	NONE,
	BUFFER_OVERFLOW,
	BIT_STUFFING_FAILURE,
	FCS_MISMATCH,
} decoder_error_t;

typedef enum {
	FLAG_SEARCH,
	FLAG_FOUND,
	FRAME_START,
	FRAME_BREAK,
	ABORT,
} decoder_state_t;

typedef struct {
	decoder_state_t decoder_state;
	uint8_t 		*frame_buffer;
	uint32_t 		frame_buffer_index;
	uint32_t 		frame_buffer_len;
	uint32_t		frame_len;
	uint8_t 		flag_buffer;
	uint8_t			flag_buffer_index;
	uint8_t			byte_buffer;
	uint8_t			byte_buffer_index;
	uint8_t 		current_nrzi_bit;
	uint8_t 		previous_nrzi_bit;
	uint8_t 		current_bit;
	uint8_t 		one_count;
	uint8_t			skip_bit_flag;
	uint8_t 		packet_rx;
} decoder_varibles_t;

/* Public Functions */
void ax25_decoder_init(uint8_t *frame_buffer, uint32_t frame_len);
void ax25_decoder_reset(void);
uint8_t ax25_decoder_get_cs(void);
uint32_t ax25_decoder_get_frame_len(void);
uint8_t * ax25_decoder_get_frame(void);
decoder_output_t ax25_decoder_feed_bit(uint8_t nrzi_bit);

#endif /* APRS_DECODER_H_ */