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50 lines
2.3 KiB
Markdown
50 lines
2.3 KiB
Markdown
# ESP Hardware Abstraction Layer for TWAI Peripheral
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> [!NOTE]
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> 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.
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## Overview
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The `esp_hal_twai` component provides a **Hardware Abstraction Layer** for the TWAI (Two-Wire Automotive Interface) peripheral across all ESP-IDF supported targets. TWAI is Espressif's implementation of the CAN (Controller Area Network) protocol, widely used in automotive and industrial applications for reliable communication between microcontrollers and devices.
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## Architecture
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The TWAI HAL is structured in two main sub-layers:
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1. **HAL Layer (Upper)**: Defines the operational steps and data structures required to control the TWAI peripheral (e.g., initialization, message transmission/reception, error handling, bus recovery).
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2. **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.
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## Supported TWAI Controllers
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This HAL supports two versions of TWAI controllers depending on the ESP chip:
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- **TWAI Version 1**: Standard CAN 2.0 controller supporting standard and extended frame formats
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- Implementation: `twai_hal_v1.c`
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- **TWAI Version 2**: Enhanced controller with TWAI-FD (CAN-FD) support, enabling flexible data-rate for higher bandwidth communication
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- Implementation: `twai_hal_v2.c`
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## Features
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- Message transmission and reception with configurable filtering
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- Standard (11-bit) and extended (29-bit) identifier support
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- Configurable bit timing and baud rates
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- Error detection and error state management
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- Bus-off recovery mechanisms
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- Interrupt-driven operations
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- Self-test mode support
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- Acceptance filters for selective message reception
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- CAN-FD support with flexible data-rate (on supported chips)
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## Usage
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The HAL functions primarily serve ESP-IDF peripheral drivers such as the `esp_driver_twai` component.
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Advanced developers can use these interfaces directly when implementing custom drivers, with the understanding that API stability is not guaranteed.
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## Dependencies
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- `soc`: Provides chip-specific register definitions
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- `hal`: Core hardware abstraction utilities and macros
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