ESP32

The ESP32 implementations: which class wraps which ESP-IDF driver, what they need, and where they differ from the interface.

Requirements

Item	Value
ESP-IDF	v5.5 or later (EspCan uses the TWAI node API introduced in v5.5)
Language	C++20, built with -fno-exceptions -fno-rtti
Primary target	ESP32-C6 (the example applications build for esp32c6)
Other targets	ESP32, -S2, -S3, -C3, -C2, -H2 are selected through McuSelect.h; peripherals a target lacks are not available (no Bluetooth on the S2: EspBluetoothStub)
ESP-IDF components	freertos, driver components, esp_wifi, bt, nvs_flash, esp_driver_i2c; esp_driver_usb_serial_jtag where the target has it

Classes

Class	Implements	ESP-IDF driver	Header	Source
EspAdc	BaseAdc	esp_adc (one-shot and continuous, calibration)	EspAdc.h	EspAdc.cpp
EspBluetooth	BaseBluetooth	NimBLE host	EspBluetooth.h	EspBluetooth.cpp
EspCan	BaseCan	TWAI node API (esp_twai)	EspCan.h	EspCan.cpp
EspGpio	BaseGpio	driver/gpio, RTC I/O, glitch filters	EspGpio.h	EspGpio.cpp
EspI2cDevice	BaseI2c	driver/i2c_master	EspI2c.h	EspI2c.cpp
EspLogger	BaseLogger	esp_log	EspLogger.h	EspLogger.cpp
EspNvs	BaseNvs	nvs_flash	EspNvs.h	EspNvs.cpp
EspPeriodicTimer	BasePeriodicTimer	esp_timer	EspPeriodicTimer.h	EspPeriodicTimer.cpp
EspPio	BasePio	RMT (driver/rmt_tx, driver/rmt_rx)	EspPio.h	EspPio.cpp
EspPwm	BasePwm	LEDC (driver/ledc)	EspPwm.h	EspPwm.cpp
EspSpiDevice	BaseSpi	driver/spi_master	EspSpi.h	EspSpi.cpp
EspTemperature	BaseTemperature	driver/temperature_sensor	EspTemperature.h	EspTemperature.cpp
EspUart	BaseUart	driver/uart	EspUart.h	EspUart.cpp
EspUsbSerialJtag	BaseUsbSerialJtag	driver/usb_serial_jtag	EspUsbSerialJtag.h	EspUsbSerialJtag.cpp
EspWifi	BaseWifi	esp_wifi	EspWifi.h	EspWifi.cpp

Shared buses are owned by a bus object: EspSpiBus creates EspSpiDevices and EspI2cBus creates EspI2cDevices. Call the bus's Initialize() before CreateDevice(); the bus keeps the devices and hands them out as BaseSpi* / BaseI2c*.

Notes by class

Class	Note
EspCan	Classic CAN only (the TWAI controller has no FD). Receive interrupt fills a lock-free ring; GetBusStatus() and RequestBusRecovery() are implemented. See CAN
EspGpio	Interrupts (ConfigureInterrupt()), glitch filters and RTC I/O for sleep are available
EspI2cDevice	Uses the ESP-IDF v5 i2c_master driver; the bus enables the internal pull-ups by default (flags.enable_internal_pullup)
EspSpiDevice	Transfer() uses spi_device_transmit(); the timeout_ms argument is reserved
EspPio	Symbol trains over RMT, for WS2812 LEDs and similar protocols
EspUsbSerialJtag	Only on targets with the USB Serial/JTAG controller (S3, C3, C6, H2, P4)

Example applications

Every ESP32 class has a test application in examples/esp32; see Examples.

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