rmt

简介

rmt 外设类型用于描述 ESP-IDF RMT 通道。BMGR 根据 role 创建 TX 或 RX channel，并返回 periph_rmt_handle_t。

该外设适用于需要直接暴露 RMT 通道句柄的板级配置。LED 灯带设备也可使用 RMT，但 led_strip 的 rmt 参数写在设备侧配置中；只有当设备显式引用已定义的 rmt 外设时，才需在 board_peripherals.yaml 中创建 rmt 外设。

支持的工作模式

rmt 按 role 区分发送与接收模式。

TX 通道
RX 通道

最小配置

TX 通道

board_peripherals.yaml：

peripherals:
  - name: rmt_tx
    type: rmt
    role: tx
    config:
      gpio_num: 18
      clk_src: RMT_CLK_SRC_DEFAULT
      resolution_hz: 10000000
      mem_block_symbols: 64
      trans_queue_depth: 4
      intr_priority: 1
      flags:
        invert_out: false
        with_dma: false
        io_od_mode: false
        allow_pd: false
        init_level: 0

RX 通道

board_peripherals.yaml：

peripherals:
  - name: rmt_rx
    type: rmt
    role: rx
    config:
      gpio_num: 19
      clk_src: RMT_CLK_SRC_DEFAULT
      resolution_hz: 1000000
      mem_block_symbols: 64
      intr_priority: 1
      flags:
        invert_in: false
        with_dma: false
        allow_pd: false

模式说明

role: tx 使用 rmt_tx_channel_config_t 字段，包含 trans_queue_depth 和 TX 输出相关 flags。role: rx 使用 rmt_rx_channel_config_t 字段，不包含 TX 队列深度。RMT 通道创建后，编码器、接收缓冲、发送或接收动作由使用该句柄的设备或应用代码配置。

IDF 5 与 IDF 6 的 RMT YAML 模板基本一致，差异在 flags：IDF 5 模板包含 io_loop_back，IDF 6 模板将开漏相关配置放入 BMGR extra flags，并且模板中不再列出 io_loop_back。

完整字段

IDF 5 TX 通道完整字段

# RMT Peripheral Default Configuration
# This file shows the default values used by the RMT peripheral parser
# Based on periph_rmt.py parsing script
# Note: Configuration now uses ESP-IDF native structures via union

# -----------------------------------------------------------------------------
# RMT TX example - Using rmt_tx_channel_config_t structure
# -----------------------------------------------------------------------------
- name: rmt_tx
  type: rmt
  role: tx
  config:
    # Basic channel configuration
    gpio_num: 18                     # [IO] GPIO number used by RMT channel. Set to -1 if unused
    clk_src: RMT_CLK_SRC_DEFAULT     # Clock source of RMT channel, channels in same group must use same clock source
                                      # Please check the 'rmt_clock_source_t' in 'driver/rmt_types.h' for valid values
    resolution_hz: 10000000          # [TO_BE_CONFIRMED] Channel clock resolution, in Hz (10MHz = 0.1us precision)
    mem_block_symbols: 64            # Size of memory block in number of rmt_symbol_word_t (even number required)
                                      # In DMA mode: controls DMA buffer size
                                      # In normal mode: controls number of RMT memory blocks
    trans_queue_depth: 4             # Depth of internal transfer queue (more transfers pending in background)
    intr_priority: 1                 # RMT interrupt priority, if set to 0, the driver will try to allocate an interrupt with a relative low priority (1,2,3)

    # TX channel flags
    flags:
      invert_out: false              # Whether to invert RMT channel signal before output to GPIO pad
      with_dma: false                # If set, allocate RMT channel with DMA capability
                                      # Please check the macro definition SOC_RMT_SUPPORT_DMA in soc/soc_caps.h
                                      # to determine whether the chip supports
      io_loop_back: false            # For debug: signal output from GPIO fed back to input path
      io_od_mode: false              # Configure GPIO as open-drain mode
      allow_pd: false                # If set, allow power domain to power off during sleep (saves power, uses more RAM)
      init_level: 0                  # Set initial level of RMT channel signal (0=low, 1=high)

IDF 5 RX 通道完整字段

# -----------------------------------------------------------------------------
# RMT RX example - Using rmt_rx_channel_config_t structure
# -----------------------------------------------------------------------------
- name: rmt_rx
  type: rmt
  role: rx
  config:
    # Basic channel configuration
    gpio_num: 19                     # [IO] GPIO number used by RMT channel. Set to -1 if unused
    clk_src: RMT_CLK_SRC_DEFAULT     # Clock source of RMT channel, channels in same group must use same clock source
                                      # Please check the 'rmt_clock_source_t' in 'driver/rmt_types.h' for valid values
    resolution_hz: 1000000           # [TO_BE_CONFIRMED] Channel clock resolution, in Hz (1MHz = 1us precision, good for 38kHz IR)
    mem_block_symbols: 64            # Size of memory block in number of rmt_symbol_word_t (even number required)
                                      # In DMA mode: controls DMA buffer size
                                      # In normal mode: controls number of RMT memory blocks
    intr_priority: 1                 # RMT interrupt priority, if set to 0, the driver will try to allocate an interrupt with a relative low priority (1,2,3)

    # RX channel flags
    flags:
      invert_in: false               # Whether to invert the incoming RMT channel signal
      with_dma: false                # If set, allocate RMT channel with DMA capability
                                      # Please check the macro definition SOC_RMT_SUPPORT_DMA in soc/soc_caps.h
                                      # to determine whether the chip supports
      io_loop_back: false            # For debug: signal output from GPIO fed back to input path
      allow_pd: false                # If set, allow power domain to power off during sleep (saves power, uses more RAM)

IDF 6 TX 通道完整字段

# RMT Peripheral Default Configuration
# This file shows the default values used by the RMT peripheral parser
# Based on periph_rmt.py parsing script
# Note: Configuration now uses ESP-IDF native structures via union

# -----------------------------------------------------------------------------
# RMT TX example - Using rmt_tx_channel_config_t structure
# -----------------------------------------------------------------------------
- name: rmt_tx
  type: rmt
  role: tx
  config:
    # Basic channel configuration
    gpio_num: 18                     # [IO] GPIO number used by RMT channel. Set to -1 if unused
    clk_src: RMT_CLK_SRC_DEFAULT     # Clock source of RMT channel, channels in same group must use same clock source
                                      # Please check the 'rmt_clock_source_t' in 'driver/rmt_types.h' for valid values
    resolution_hz: 10000000          # [TO_BE_CONFIRMED] Channel clock resolution, in Hz (10MHz = 0.1us precision)
    mem_block_symbols: 64            # Size of memory block in number of rmt_symbol_word_t (even number required)
                                      # In DMA mode: controls DMA buffer size
                                      # In normal mode: controls number of RMT memory blocks
    trans_queue_depth: 4             # Depth of internal transfer queue (more transfers pending in background)
    intr_priority: 1                 # RMT interrupt priority, if set to 0, the driver will try to allocate an interrupt with a relative low priority (1,2,3)

    # TX channel flags
    flags:
      invert_out: false              # Whether to invert RMT channel signal before output to GPIO pad
      with_dma: false                # If set, allocate RMT channel with DMA capability
                                      # Please check the macro definition SOC_RMT_SUPPORT_DMA in soc/soc_caps.h
                                      # to determine whether the chip supports
      io_od_mode: false              # Configure GPIO as open-drain mode
      allow_pd: false                # If set, allow power domain to power off during sleep (saves power, uses more RAM)
      init_level: 0                  # Set initial level of RMT channel signal (0=low, 1=high)

IDF 6 RX 通道完整字段

# -----------------------------------------------------------------------------
# RMT RX example - Using rmt_rx_channel_config_t structure
# -----------------------------------------------------------------------------
- name: rmt_rx
  type: rmt
  role: rx
  config:
    # Basic channel configuration
    gpio_num: 19                     # [IO] GPIO number used by RMT channel. Set to -1 if unused
    clk_src: RMT_CLK_SRC_DEFAULT     # Clock source of RMT channel, channels in same group must use same clock source
                                      # Please check the 'rmt_clock_source_t' in 'driver/rmt_types.h' for valid values
    resolution_hz: 1000000           # [TO_BE_CONFIRMED] Channel clock resolution, in Hz (1MHz = 1us precision, good for 38kHz IR)
    mem_block_symbols: 64            # Size of memory block in number of rmt_symbol_word_t (even number required)
                                      # In DMA mode: controls DMA buffer size
                                      # In normal mode: controls number of RMT memory blocks
    intr_priority: 1                 # RMT interrupt priority, if set to 0, the driver will try to allocate an interrupt with a relative low priority (1,2,3)

    # RX channel flags
    flags:
      invert_in: false               # Whether to invert the incoming RMT channel signal
      with_dma: false                # If set, allocate RMT channel with DMA capability
                                      # Please check the macro definition SOC_RMT_SUPPORT_DMA in soc/soc_caps.h
                                      # to determine whether the chip supports
      allow_pd: false                # If set, allow power domain to power off during sleep (saves power, uses more RAM)

适用设备

device type	使用方式	说明
`led_strip`	`sub_type` 为 `rmt` 时使用 RMT 驱动能力	当前 `led_strip` 设备模板把 `rmt` 参数放在设备侧 `config.rmt` 中，不要求引用独立 `rmt` 外设
`custom`	设备侧可引用已定义的 `rmt` 外设	编码器、发送队列使用方式和接收缓冲由自定义设备或应用代码决定

参考代码

esp_board_manager/peripherals/periph_rmt/idf5/periph_rmt.c
esp_board_manager/peripherals/periph_rmt/idf6/periph_rmt.c
esp_board_manager/test_apps/main/periph/test_periph_rmt.c

板级参考

esp_board_manager/test_apps/components/board_customer/boards/esp32_s3_devkitc/board_peripherals.yaml：定义 rmt_tx 测试外设。
esp_board_manager/boards/esp32_s31_korvo1/board_devices.yaml：led_strip 使用 sub_type: rmt。
esp_board_manager/boards/esp32_s31_function_coreboard_1/board_devices.yaml：led_strip 使用 sub_type: rmt。

注意事项

同一 RMT group 内 channel 的 clk_src 需要一致，模板注释中已标出该限制。
with_dma 只在目标芯片支持 RMT DMA 时可用。
role 决定解析 TX 还是 RX 配置。TX 专用字段不要写入 RX 外设，RX 专用字段不要写入 TX 外设。
修改 RMT 外设配置后，需要重新执行 idf.py bmgr -b <board>。

调试技巧

API 参考

使用 esp_board_manager_get_periph_handle() 获取 RMT 外设句柄，句柄类型为 periph_rmt_handle_t：

typedef struct {
    rmt_channel_handle_t  channel;  /*!< Generic RMT channel handle */
} periph_rmt_handle_t;

channel 可传入 rmt_transmit、rmt_receive 等 ESP-IDF RMT API；具体可用接口取决于 board_peripherals.yaml 中 role 配置为 TX 还是 RX。

相关声明位于 esp_board_manager/peripherals/periph_rmt/periph_rmt.h。

底层 ESP-IDF 驱动文档：红外遥控 (RMT)。

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