qmk_firmware/keyboards/annepro2/protocol.h

/*
 * (c) 2021 by Tomasz bla Fortuna
 * License: GPLv2
 *
 * This file is shared with the Shine firmware. Keep it in sync (and in the
 * shine's clang formatting).
 */

#pragma once
#include <stdint.h>

#define PROTOCOL_SD SD0

enum {
    /*
     * Main -> LED
     */
    /* Basic config */
    CMD_LED_ON  = 0x01,
    CMD_LED_OFF = 0x02,

    CMD_LED_SET_PROFILE  = 0x03,
    CMD_LED_NEXT_PROFILE = 0x04,
    CMD_LED_PREV_PROFILE = 0x05,

    CMD_LED_NEXT_INTENSITY       = 0x06,
    CMD_LED_NEXT_ANIMATION_SPEED = 0x07,

    /* Masks */
    /* Override a key color, eg. capslock */
    CMD_LED_MASK_SET_KEY = 0x10,
    /* Override all keys in a row with configurable colors */
    CMD_LED_MASK_SET_ROW = 0x11,

    /* Override all keys with single color (eg. foreground color) */
    CMD_LED_MASK_SET_MONO = 0x12,

    /* Reactive / status */
    CMD_LED_GET_STATUS = 0x20,
    CMD_LED_KEY_BLINK  = 0x21,
    CMD_LED_KEY_DOWN   = 0x22,
    CMD_LED_KEY_UP     = 0x23, /* TODO */
    CMD_LED_IAP        = 0x24,

    /* LED -> Main */
    /* Payload with data to send over HID */
    CMD_LED_DEBUG = 0x40,

    /* Number of profiles, current profile, on/off state,
       reactive flag, brightness, errors */
    CMD_LED_STATUS = 0x41,
};

/* 1 ROW * 14 COLS * 4B (RGBX) = 56 + header prefix. */
#define MAX_PAYLOAD_SIZE 64

/** Enum of the states used for the serial protocol finite-state automaton */
enum proto_state {
    /* 2-byte initial start-of-message sync */
    STATE_SYNC_1,
    STATE_SYNC_2,
    /* Waiting for command byte */
    STATE_CMD,
    /* Waiting for ID byte */
    STATE_ID,
    /* Waiting for payload size */
    STATE_PAYLOAD_SIZE,
    /* Reading payload until payload_position == payload_size */
    STATE_PAYLOAD,
};

/* Buffer holding a single message */
typedef struct {
    uint8_t command;
    uint8_t msg_id;
    uint8_t payload_size;
    uint8_t payload[MAX_PAYLOAD_SIZE];
} message_t;

/* Internal protocol state */
typedef struct {
    /* Callback to call upon receiving a valid message */
    void (*callback)(const message_t *);

    /* Number of read payload bytes */
    uint8_t payload_position;

    /* Current finite-state-automata state */
    enum proto_state state;

    uint8_t previous_id;
    uint8_t errors;

    /* Currently received message */
    message_t buffer;
} protocol_t;

/* NOTE: This didn't work when defined on stack */
extern protocol_t proto;

/* Init state */
extern void proto_init(protocol_t *proto, void (*callback)(const message_t *));

/* Consume one byte and push state forward - might call the callback */
extern void proto_consume(protocol_t *proto, uint8_t byte);

/* Prolonged silence - reset state */
extern void proto_silence(protocol_t *proto);

/* Transmit message */
extern void proto_tx(uint8_t cmd, const unsigned char *buf, int payload_size, int retries);