Migration from 2.x to 3.0

Introduction

This is a guide to highlight breaking changes in the API and build system to help the migration of projects from versions 2.X (based on ESP-IDF 4.4) to version 3.0 (based on ESP-IDF 5.1) of the Arduino ESP32 core.

All the examples on the version 3.0.0 were updated to be compatible to the new API. The old examples from the versions below 3.0.0 will be not compatible with the version 3.0.0 or newer releases.

For more information about all changes and new features, check project RELEASE NOTES.

Build System

Compilation Flags

Functional changes

If your project uses extra flags in the compilation process, it will now overwrite some required default flags. To ensure your project compiles correctly, make sure to have the -MMD -c flags in your C and C++ extra flags.

APIs

ADC

Removed APIs

analogSetClockDiv
adcAttachPin
analogSetVRefPin

BLE

Changes in APIs

Changed APIs return and parameter type from std::string to Arduino style String.
Changed UUID data type from uint16_t to BLEUUID class.
BLEScan::start and BLEScan::getResults methods return type changed from BLEScanResults to BLEScanResults*.

Hall Sensor

Hall sensor is no longer supported.

Removed APIs

hallRead

I2S

The I2S driver has been completely redesigned and refactored to use the new ESP-IDF driver. For more information about the new API, check I2S.

LEDC

The LEDC API has been changed in order to support the Peripheral Manager and make it easier to use, as LEDC channels are now automatically assigned to pins. For more information about the new API, check LED Control (LEDC).

Removed APIs

ledcSetup
ledcAttachPin

New APIs

ledcAttach used to set up the LEDC pin (merged ledcSetup and ledcAttachPin functions).
ledcOutputInvert used to attach the interrupt to a timer using arguments.
ledcFade used to set up and start a fade on a given LEDC pin.
ledcFadeWithInterrupt used to set up and start a fade on a given LEDC pin with an interrupt.
ledcFadeWithInterruptArg used to set up and start a fade on a given LEDC pin with an interrupt using arguments.

Changes in APIs

ledcDetachPin renamed to ledcDetach.
In all functions, input parameter channel has been changed to pin.

RMT

For more information about the new API, check RMT.

Removed APIs

_rmtDumpStatus
rmtSetTick
rmtWriteBlocking
rmtEnd
rmtBeginReceive
rmtReadData

New APIs

rmtSetEOT
rmtWriteAsync
rmtTransmitCompleted
rmtSetRxMinThreshold

Changes in APIs

In all functions, input parameter rmt_obj_t* rmt has been changed to int pin.
rmtInit return parameter changed to bool.
rmtInit input parameter bool tx_not_rx has been changed to rmt_ch_dir_t channel_direction.
rmtInit new input parameter uint32_t frequency_Hz to set frequency of RMT channel (as function rmtSetTick was removed).
rmtWrite now sending data in blocking mode. It only returns after sending all data or through a timeout. For Async mode use the new rmtWriteAsync function.
rmtWrite new input parameter uint32_t timeout_ms.
rmtLoop renamed to rmtWriteLooping.
rmtRead input parameters changed to int pin, rmt_data_t* data, size_t *num_rmt_symbols, uint32_t timeout_ms.
rmtReadAsync input parameters changed to int pin, rmt_data_t* data, size_t *num_rmt_symbols.
rmtSetRxThreshold renamed to rmtSetRxMaxThreshold and input parameter uint32_t value has been changed to uint16_t idle_thres_ticks.
rmtSetCarrier input parameters uint32_t low, uint32_t high have been changed to uint32_t frequency_Hz, float duty_percent.

SigmaDelta

SigmaDelta has been refactored to use the new ESP-IDF driver. For more information about the new API, check SigmaDelta.

Removed APIs

sigmaDeltaSetup
sigmaDeltaRead

New APIs

sigmaDeltaAttach used to set up the SigmaDelta pin (channel is acquired automatically).
timerGetFrequency used to get the actual frequency of the timer.
timerAttachInterruptArg used to attach the interrupt to a timer using arguments.

Changes in APIs

sigmaDeltaDetachPin renamed to sigmaDeltaDetach.
sigmaDeltaWrite input parameter channel has been changed to pin.

Timer

Timer has been refactored to use the new ESP-IDF driver and its API got simplified. For more information about the new API check Timer.

Removed APIs

timerGetConfig
timerSetConfig
timerSetDivider
timerSetCountUp
timerSetAutoReload
timerGetDivider
timerGetCountUp
timerGetAutoReload
timerAlarmEnable
timerAlarmDisable
timerAlarmWrite
timerAlarmEnabled
timerAlarmRead
timerAlarmReadMicros
timerAlarmReadSeconds
timerAttachInterruptFlag

New APIs

timerAlarm used to set up Alarm for the timer and enable it automatically (merged timerAlarmWrite and timerAlarmEnable functions).
timerGetFrequency used to get the actual frequency of the timer.
timerAttachInterruptArg used to attach the interrupt to a timer using arguments.

Changes in APIs

timerBegin has now only 1 parameter (frequency). There is an automatic calculation of the divider using different clock sources to achieve the selected frequency.
timerAttachInterrupt has now only 2 parameters. The edge parameter has been removed.

UART (HardwareSerial)

Changes in APIs

setHwFlowCtrlMode input parameter uint8_t mode has been changed to SerialHwFlowCtrl mode.
setMode input parameter uint8_t mode has been changed to SerialMode mode.

Functional changes

Default pins for some SoCs have been changed to avoid conflicts with other peripherals: * ESP32’s UART1 RX and TX pins are now GPIO26 and GPIO27, respectively; * ESP32’s UART2 RX and TX pins are now GPIO4 and GPIO25, respectively; * ESP32-S2’s UART1 RX and TX pins are now GPIO4 and GPIO5, respectively.
It is now possible to detach UART0 pins by calling end() with no previous call of begin().
It is now possible to call setPins() before begin() or in any order.
setPins() will detach any previous pins that have been changed.
begin(baud, rx, tx) will detach any previous attached pins.
setPins() or begin(baud, rx, tx) when called at first, will detach console RX0/TX0, attached in boot.
Any pin set as -1 in begin() or setPins() won’t be changed nor detached.
begin(baud) will not change any pins that have been set before this call, through a previous begin(baud, rx, tx) or setPin().
If the application only uses RX or TX, begin(baud, -1, tx) or begin(baud, rx) will change only the assigned pin and keep the other unchanged.

Wi-Fi

Functional changes

In Arduino (and other frameworks) the method named flush() is intended to send out the transmit buffer content. WiFiClient and WiFiUDP method flush() won’t clear the receive buffer anymore. A new method called clear() is now used for that. Currently flush() does nothing in WiFiClient, WiFiClientSecure and WiFiUDP.
WiFiServer has functions accept() and available() with the same functionality. In Arduino, available() should work differently so it is now deprecated.
WiFiServer had unimplemented write functions inherited from Print class. These are now removed. Also unimplemented method stopAll() is removed. The methods were unimplemented because WiFiServer doesn’t manage connected WiFiClient objects for print-to-all-clients functionality.