Skip to content

BSP Buzzer Module

BSP Buzzer Module

Board-level view of the buzzer: how a BSP wires the shared LEDC driver. The application side (sound events, priorities, customization) is the sound module, documented in buzzer.md and sound_system.md.

The former application layer (Buzzer class / esp3d_buzzer, esp3d_notes.h, blocking buzzer_bip(), malloc + task based buzzer_play(), buzzer_tone.h) was removed in a14.

Stack

Board Constants (`board_config.h`, PiBot)

Constant	Value	Meaning
`BUZZER_PIN`	`GPIO_NUM_26`	Buzzer GPIO
`BUZZER_ACTIVE_HIGH_FLAG`	`1`	GPIO level for buzzer on
`BUZZER_PWM_FREQ_HZ`	`1000`	Default PWM frequency (each note sets its own)
`BUZZER_PWM_RESOLUTION_BITS`	`10`	Duty resolution
`BUZZER_PWM_TIMER_IDX` / `BUZZER_PWM_CHANNEL_IDX`	`1` / `1`	LEDC timer / channel
`BUZZER_PWM_DUTY_PERCENT`	`15`	Volume (1–50 %, 50 = loudest); lowered because SC8002B current peaks on fast repeated key beeps are suspected of causing BROWNOUT resets (2026-11-01, not confirmed on hardware)

`buzzer_def.h`

buzzer_config_t buzzer_cfg = {
    .output_invert   = !BUZZER_ACTIVE_HIGH_FLAG, // Invert if not active-high
    .gpio_num        = BUZZER_PIN,
    .timer_idx       = BUZZER_PWM_TIMER_IDX,
    .channel_idx     = BUZZER_PWM_CHANNEL_IDX,
    .freq_hz         = BUZZER_PWM_FREQ_HZ,
    .resolution_bits = BUZZER_PWM_RESOLUTION_BITS,
    .duty_percent    = BUZZER_PWM_DUTY_PERCENT,
};

`board_init()`

#if (ESP3D_BUZZER_FEATURE)
    ret = buzzer_configure(&buzzer_cfg);
    if (ret != ESP_OK)
    {
        esp3d_log_e("Buzzer initialization failed");
        return ret;
    }
#endif  // ESP3D_BUZZER_FEATURE

Driver API (`hardware/common/drivers/buzzer/buzzer.h`)

Function	Description
`buzzer_configure(const buzzer_config_t *config)`	LEDC timer + channel setup for the buzzer GPIO
`buzzer_tone_start(uint16_t freq_hz)`	Continuous tone, non-blocking, safe from an `esp_timer` callback; `0` = silence
`buzzer_tone_stop(void)`	Silence, non-blocking

Only the sound module’s tone backend calls buzzer_tone_start() / buzzer_tone_stop(), from its esp_timer callback, so there is no concurrent LEDC access.

Boards without a buzzer leave BUZZER_SERVICE OFF (today only pibot_pendant_v1_0 enables it). The Factory apps and the PiBot custom bootloader have their own standalone buzzer code, see buzzer.md “Factory App & Bootloader Buzzer”.

buzzer — sound module, events, customization
bsp_board_initialization — board_init()
pibot_pendant_v1_0_bsp — PiBot BSP