DShotRMT/src/dshot_init.cpp

/**
 * @file dshot_init.cpp
 * @brief RMT configuration and initialization functions for DShotRMT library
 * @author Wastl Kraus
 * @date 2025-10-04
 * @license MIT
 */

#include "dshot_init.h"

// Function to initialize the RMT TX channel
dshot_result_t init_rmt_tx_channel(gpio_num_t gpio, rmt_channel_handle_t *out_channel, bool is_bidirectional)
{
    rmt_tx_channel_config_t tx_channel_config = {
        .gpio_num = gpio,
        .clk_src = DSHOT_CLOCK_SRC_DEFAULT,
        .resolution_hz = DSHOT_RMT_RESOLUTION,
        .mem_block_symbols = RMT_BUFFER_SYMBOLS,
        .trans_queue_depth = RMT_QUEUE_DEPTH,
        .flags = {
            .invert_out = is_bidirectional ? 1 : 0,
            .init_level = is_bidirectional ? 0 : 1}};

    rmt_transmit_config_t rmt_tx_config = {}; // Initialize all members to zero
    rmt_tx_config.loop_count = 0;             // No automatic loops - real-time calculation

    if (rmt_new_tx_channel(&tx_channel_config, out_channel) != DSHOT_OK)
    {
        return {false, DSHOT_TX_INIT_FAILED};
    }

    if (rmt_enable(*out_channel) != DSHOT_OK)
    {
        return {false, DSHOT_TX_INIT_FAILED};
    }

    return {true, DSHOT_TX_INIT_SUCCESS};
}

// Function to initialize the RMT RX channel
dshot_result_t init_rmt_rx_channel(gpio_num_t gpio, rmt_channel_handle_t *out_channel, rmt_rx_event_callbacks_t *rx_event_callbacks, void *user_data)
{
    rmt_rx_channel_config_t rx_channel_config = {
        .gpio_num = gpio,
        .clk_src = DSHOT_CLOCK_SRC_DEFAULT,
        .resolution_hz = DSHOT_RMT_RESOLUTION,
        .mem_block_symbols = RMT_BUFFER_SYMBOLS,
    };

    if (rmt_new_rx_channel(&rx_channel_config, out_channel) != DSHOT_OK)
    {
        return {false, DSHOT_RX_INIT_FAILED};
    }

    if (rmt_rx_register_event_callbacks(*out_channel, rx_event_callbacks, user_data) != DSHOT_OK)
    {
        return {false, DSHOT_CALLBACK_REGISTERING_FAILED};
    }

    if (rmt_enable(*out_channel) != DSHOT_OK)
    {
        return {false, DSHOT_RX_INIT_FAILED};
    }

    return {true, DSHOT_RX_INIT_SUCCESS};
}

// Function to initialize the DShot RMT encoder
dshot_result_t init_dshot_encoder(rmt_encoder_handle_t *out_encoder, const rmt_ticks_t &rmt_ticks, uint16_t pulse_level, uint16_t idle_level)
{
    rmt_bytes_encoder_config_t encoder_config = {
        .bit0 = {
            .duration0 = rmt_ticks.t0h_ticks,
            .level0 = pulse_level,
            .duration1 = rmt_ticks.t0l_ticks,
            .level1 = idle_level,
        },
        .bit1 = {
            .duration0 = rmt_ticks.t1h_ticks,
            .level0 = pulse_level,
            .duration1 = rmt_ticks.t1l_ticks,
            .level1 = idle_level,
        },

        .flags = {
            .msb_first = 1 // DShot is MSB first
        }};

    if (rmt_new_bytes_encoder(&encoder_config, out_encoder) != DSHOT_OK)
    {
        return {false, DSHOT_ENCODER_INIT_FAILED};
    }

    return {true, DSHOT_ENCODER_INIT_SUCCESS};
}