#ifndef DISPLAY_AVR_3_HDLC_H
#define DISPLAY_AVR_3_HDLC_H

#define HDLC_MRU    256
// HDLC constants --- RFC 1662
#define HDLC_FLAG_SOF				  0x7e   // Flag
#define HDLC_CONTROL_ESCAPE 	0x7d   // Control Escape octet
#define HDLC_ESCAPE_BIT     	0x20   // Transparency modifier octet (XOR bit)
#define HDLC_CRC_INIT_VAL   	0xffff
#define HDLC_CRC_MAGIC_VAL   	0xf0b8
#define HDLC_CRC_POLYNOMIAL  	0x8408
#define HDLC_UI_CMD						0x03     // Unnumbered Information with payload
#define HDLC_FINAL_FLAG       0x10     // F flag
#define HDLC_POLL_FLAG       0x10      // P flag

typedef enum
{
    HDLC_SOF_WAIT,
    HDLC_DATARX,
    HDLC_PROC_ESC,
} hdlc_state_t;

typedef struct
{
    uint8_t				own_addr;
    uint8_t				src_addr;
    uint8_t  			dest_addr;
    uint8_t 			ctrl;
    uint8_t				*p_tx_frame;			// tx frame buffer
    uint8_t 			*p_rx_frame;			// rx frame buffer
    uint8_t				*p_payload;				// payload pointer
    uint16_t   		rx_frame_index;
    uint16_t			rx_frame_fcs;
    hdlc_state_t	state;
} hdlc_t;


void hdlc_init(void);

void hdlc_process_rx_frame(uint8_t *buf, uint16_t len);
void hdlc_tx_frame(const uint8_t *txbuffer, uint8_t len);

#endif //DISPLAY_AVR_3_HDLC_H