anacmpr

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Overview

The anacmpr peripheral type describes an on-chip analog comparator unit. BMGR generates an ana_cmpr_config_t from this configuration and calls the ESP-IDF driver/ana_cmpr.h to create the analog comparator unit.

After BMGR initialization, the application retrieves the periph_anacmpr_handle_t via esp_board_manager_get_periph_handle() and then uses the ESP-IDF analog comparator APIs to configure the internal reference, level-crossing callback, debounce, and start/stop actions.

Supported Operating Modes

anacmpr does not use role or format to split modes. The configuration axis is a single analog comparator unit.

Minimal Configuration

Analog Comparator Unit

board_peripherals.yaml:

peripherals:
  - name: anacmpr_unit_0
    type: anacmpr
    config:
      unit: 0
      ref_src: ANA_CMPR_REF_SRC_INTERNAL
      cross_type: ANA_CMPR_CROSS_ANY
      clk_src: ANA_CMPR_CLK_SRC_DEFAULT
      intr_priority: 0

Mode Description

anacmpr creates one analog comparator unit. ref_src selects the internal or external reference input, cross_type selects the crossing direction that triggers the event, and intr_priority configures the interrupt priority.

The current BMGR parser only accepts unit: 0. The internal reference voltage, debounce, and event callbacks are not configured in the peripheral YAML; they must be set by the application after obtaining the handle via the ESP-IDF analog comparator APIs.

Full Field Reference

Analog Comparator Unit — Full Fields

# Analog Comparator example with internal reference
- name: anacmpr_unit_0
  type: anacmpr
  config:
    # Analog Comparator unit number, must be not less than 0 and less than 'SOC_ANA_CMPR_NUM'  (default: 0)
    # Please check the 'SOC_ANA_CMPR_NUM' in 'soc/soc_caps.h' for valid values
    unit: 0  # [TO_BE_CONFIRMED] Analog Comparator unit

    # Reference source type (default: ANA_CMPR_REF_SRC_INTERNAL)
    ref_src: ANA_CMPR_REF_SRC_INTERNAL  # [TO_BE_CONFIRMED] Reference source type
    # Valid values:
    # - ANA_CMPR_REF_SRC_INTERNAL: Use internal reference voltage (divided from VDD)
    # - ANA_CMPR_REF_SRC_EXTERNAL: Use external reference from GPIO pin

    # Cross type for interrupt triggering (default: ANA_CMPR_CROSS_ANY)
    cross_type: ANA_CMPR_CROSS_ANY
    # Valid values:
    # - ANA_CMPR_CROSS_POS: Trigger on positive crossing (source > reference)
    # - ANA_CMPR_CROSS_NEG: Trigger on negative crossing (source < reference)
    # - ANA_CMPR_CROSS_ANY: Trigger on both positive and negative crossing

    # Clock source (default: ANA_CMPR_CLK_SRC_DEFAULT)
    clk_src: ANA_CMPR_CLK_SRC_DEFAULT
    # Please check the 'soc_periph_ana_cmpr_clk_src_t' in 'soc/clk_tree_defs.h' for valid values

    # Interrupt priority (default: 0)
    # If set to 0, the driver will automatically select a relative low priority (1,2,3)
    intr_priority: 0

Field sources:

  • YAML template: esp_board_manager/peripherals/periph_anacmpr/periph_anacmpr.yml.

  • Header file: esp_board_manager/peripherals/periph_anacmpr/periph_anacmpr.h.

Applicable Devices

device type

Usage

Notes

Direct application use

Application retrieves the analog comparator peripheral handle via esp_board_manager_get_periph_handle

No device type in the current repository references the anacmpr peripheral; reference voltage, debounce, callbacks, and start/stop are handled by application or test code

Reference Code

  • esp_board_manager/test_apps/main/periph/test_periph_anacmpr.c

Board-Level Reference

  • esp_board_manager/test_apps/components/board_customer/boards/esp32_p4_core/board_peripherals.yaml: anacmpr_unit_0 configuration, along with gpio_monitor for observing crossing events during testing.

Notes

  • The current parser only accepts unit: 0.

  • ref_src only accepts ANA_CMPR_REF_SRC_INTERNAL or ANA_CMPR_REF_SRC_EXTERNAL.

  • cross_type only accepts ANA_CMPR_CROSS_POS, ANA_CMPR_CROSS_NEG, or ANA_CMPR_CROSS_ANY.

  • clk_src currently only accepts ANA_CMPR_CLK_SRC_DEFAULT.

  • The internal reference voltage, debounce, and event callbacks must be configured in application code and must not be written into the anacmpr peripheral config.

  • After modifying the analog comparator peripheral configuration, re-run idf.py bmgr -b <board>.

Debugging Tips

API Reference

Use esp_board_manager_get_periph_handle() to retrieve the analog comparator peripheral handle. The handle type is periph_anacmpr_handle_t:

typedef struct {
    ana_cmpr_handle_t  cmpr_handle;  /*!< Analog comparator handle */
    ana_cmpr_unit_t    unit;         /*!< Analog comparator unit */
} periph_anacmpr_handle_t;

cmpr_handle can be passed to the ESP-IDF ana_cmpr_* APIs. unit identifies the current comparator controller number.

Related declarations are in esp_board_manager/peripherals/periph_anacmpr/periph_anacmpr.h.

Underlying ESP-IDF driver documentation: Analog Comparator.

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