Chapter 2. API Reference
Application Example
• Pulse counter with control signal and event interrupt example: peripherals/pcnt/pulse_count_event.
• Parse the signal generated from rotary encoder: peripherals/pcnt/rotary_encoder.
API Reference
Header File
• components/driver/include/driver/pcnt.h
Functions
esp_err_t pcnt_unit_config(const pcnt_config_t *pcnt_config)
Configure Pulse Counter unit.
Note This function will disable three events: PCNT_EVT_L_LIM, PCNT_EVT_H_LIM,
PCNT_EVT_ZERO.
Return
• ESP_OK Success
• ESP_ERR_INVALID_STATE pcnt driver already initialized
• ESP_ERR_INVALID_ARG Parameter error
Parameters
• pcnt_config: Pointer of Pulse Counter unit configure parameter
esp_err_t pcnt_get_counter_value(pcnt_unit_t pcnt_unit, int16_t *count)
Get pulse counter value.
Return
• ESP_OK Success
• ESP_ERR_INVALID_STATE pcnt driver has not been initialized
• ESP_ERR_INVALID_ARG Parameter error
Parameters
• pcnt_unit: Pulse Counter unit number
• count: Pointer to accept counter value
esp_err_t pcnt_counter_pause(pcnt_unit_t pcnt_unit)
Pause PCNT counter of PCNT unit.
Return
• ESP_OK Success
• ESP_ERR_INVALID_STATE pcnt driver has not been initialized
• ESP_ERR_INVALID_ARG Parameter error
Parameters
• pcnt_unit: PCNT unit number
esp_err_t pcnt_counter_resume(pcnt_unit_t pcnt_unit)
Resume counting for PCNT counter.
Return
• ESP_OK Success
• ESP_ERR_INVALID_STATE pcnt driver has not been initialized
• ESP_ERR_INVALID_ARG Parameter error
Parameters
• pcnt_unit: PCNT unit number, select from pcnt_unit_t
esp_err_t pcnt_counter_clear(pcnt_unit_t pcnt_unit)
Clear and reset PCNT counter value to zero.
Return
• ESP_OK Success
• ESP_ERR_INVALID_STATE pcnt driver has not been initialized
• ESP_ERR_INVALID_ARG Parameter error
Espressif Systems 331
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