uart_driver_install() function

UART port number, the max port number is (UART_NUM_MAX -1).

UART RX ring buffer size.

UART TX ring buffer size. If set to zero, driver will not use TX buffer, TX function will block task until all data have been sent out.

UART event queue size/depth.

UART event queue handle (out param). On success, a new queue handle is written here to provide access to UART events. If set to NULL, driver will not use an event queue.

Flags used to allocate the interrupt. One or multiple (ORred) ESP_INTR_FLAG_* values. See esp_intr_alloc.h for more info. Do not set ESP_INTR_FLAG_IRAM here (the driver's ISR handler is not located in IRAM)