Note

This component is currently in beta. Its API, behavior, and compatibility may change at any time and without notice; backward compatibility is not guaranteed. Use caution when integrating into production systems.

Overview

The esp_hal_uart component provides a Hardware Abstraction Layer for Universal Asynchronous Receiver/Transmitter (UART) peripherals across all ESP-IDF supported targets. It also includes support for UHCI (Universal Host Controller Interface) on chips where it is available and enabled.

Architecture

The UART HAL is structured in two main sub-layers:

HAL Layer (Upper): Defines the operational steps and data structures required to control UART/UHCI peripherals (e.g., initialization, configuration, data movement, power-management hooks).
Low-Level Layer (Bottom): Serves as a translation layer between the HAL and the register files defined in the soc component, handling target-specific register configurations.

Supported Controllers

UART: Standard UART controller available on all supported ESP chips
UHCI: Available on selected chips; built when CONFIG_SOC_UHCI_SUPPORTED is enabled

Features

Configurable baud rate, data bits, parity, and stop bits
Hardware and software flow control (on supported chips)
RX/TX FIFO management
Interrupt-driven operations
DMA support on capable chips
Clock source selection (on supported chips)
Light-sleep and wakeup helpers (on supported chips)

Usage

The HAL functions primarily serve ESP-IDF peripheral drivers such as esp_driver_uart.

Advanced developers can use these interfaces directly when implementing custom drivers, with the understanding that API stability is not guaranteed.

Dependencies

soc: Provides chip-specific register definitions
hal: Core hardware abstraction utilities and macros