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53 lines
3.0 KiB
Markdown
53 lines
3.0 KiB
Markdown
# ESP Hardware Abstraction Layer for Touch Sensor 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_touch_sens` component provides a **Hardware Abstraction Layer** for Touch Sensor controller supported targets. Touch sensors detect touch events by measuring changes in capacitance when a finger or object approaches the touch pad, enabling capacitive touch interfaces for user interaction.
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## Architecture
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The Touch Sensor 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 touch sensor peripherals (e.g., initialization, channel configuration, filter setup, measurement control).
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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 Touch Sensor Controllers
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This HAL supports various touch sensor controller versions depending on the ESP chip:
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- **Touch Sensor Version 1**: Basic touch sensor functionality (ESP32)
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- **Touch Sensor Version 2**: Enhanced features including improved filtering and denoise capabilities (ESP32-S2, ESP32-S3)
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- **Touch Sensor Version 3**: Advanced features with frequency hopping, multiple sample configurations, and enhanced waterproof support (ESP32-P4 and newer chips)
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## Features
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- **Channel Management**: Multi-channel touch pad support with independent configuration
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- **Measurement Control**: Configurable charge/discharge cycles, voltage thresholds, and measurement intervals
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- **Filtering and Signal Processing**:
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- Benchmark filter (IIR filter, jitter filter)
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- Smooth data filter for noise reduction
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- Debounce and noise threshold configuration
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- Active threshold hysteresis
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- **Denoise Function**: Internal denoise channel (T0) to filter out power supply noise and external EMI
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- **Waterproof Support**: Guard pad and shield channel configuration for water-resistant applications
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- **Proximity Sensing**: Up to three touch channels can be configured as proximity sensors
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- **Sleep Channel**: Deep sleep wake-up support with configurable sleep channel
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- **FSM Operation**: Hardware timer or software-triggered measurement modes
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- **Interrupt Handling**: Multiple interrupt types (active, inactive, done, scan done, timeout, proximity done)
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- **Sample Configuration**: Multiple sample configurations with frequency hopping support (Version 3)
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## Usage
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The HAL functions primarily serve ESP-IDF peripheral drivers such as `esp_driver_touch_sens`.
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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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