Espressif ESP32-S2 User Manual

Chapter 2. API Reference
• uart_num: UART port number, the max port number is (UART_NUM_MAX -1).
esp_err_t uart_flush_input(uart_port_t uart_num)
Clear input buffer, discard all the data is in the ring-buffer.
Note In order to send all the data in tx FIFO, we can use uart_wait_tx_done function.
Return
• ESP_OK Success
• ESP_FAIL Parameter error
Parameters
• uart_num: UART port number, the max port number is (UART_NUM_MAX -1).
esp_err_t uart_get_buffered_data_len(uart_port_t uart_num, size_t *size)
UART get RX ring buffer cached data length.
Return
• ESP_OK Success
• ESP_FAIL Parameter error
Parameters
• uart_num: UART port number, the max port number is (UART_NUM_MAX -1).
• size: Pointer of size_t to accept cached data length
esp_err_t uart_disable_pattern_det_intr(uart_port_t uart_num)
UART disable pattern detect function. Designed for applications like‘AT commands’. When the hardware
detects a series of one same character, the interrupt will be triggered.
Return
• ESP_OK Success
• ESP_FAIL Parameter error
Parameters
• uart_num: UART port number, the max port number is (UART_NUM_MAX -1).
esp_err_t uart_enable_pattern_det_baud_intr(uart_port_t uart_num, char pattern_chr,
uint8_t chr_num, int chr_tout, int post_idle, int
pre_idle)
UART enable pattern detect function. Designed for applications like ‘AT commands’. When the hardware
detect a series of one same character, the interrupt will be triggered.
Return
• ESP_OK Success
• ESP_FAIL Parameter error
Parameters
• uart_num: UART port number.
• pattern_chr: character of the pattern.
• chr_num: number of the character, 8bit value.
• chr_tout: timeout of the interval between each pattern characters, 16bit value, unit is the baud-
rate cycle you configured. When the duration is more than this value, it will not take this data as
at_cmd char.
• post_idle: idle time after the last pattern character, 16bit value, unit is the baud-rate cycle you
configured. When the duration is less than this value, it will not take the previous data as the last
at_cmd char
• pre_idle: idle time before the first pattern character, 16bit value, unit is the baud-rate cycle you
configured. When the duration is less than this value, it will not take this data as the first at_cmd
char.
int uart_pattern_pop_pos(uart_port_t uart_num)
Return the nearest detected pattern position in buffer. The positions of the detected pattern are saved in a
queue, this function will dequeue the first pattern position and move the pointer to next pattern position.
The following APIs will modify the pattern position info: uart_flush_input, uart_read_bytes,
uart_driver_delete, uart_pop_pattern_pos It is the application’s responsibility to ensure atomic access
to the pattern queue and the rx data buffer when using pattern detect feature.
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Release v4.4

Espressif ESP32-S2 Specifications

General

Brand	Espressif
Model	ESP32-S2
Category	Single board computers
Language	English