CHANGELOG.md

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

Fixed

• PinDriver now routes the pad to the GPIO function before setting its direction. A pin whose IO_MUX.MCU_SEL boots on an alternate function - JTAG, SPI flash, UART - stayed on that function, so set_high/set_low never reached the pad (#585)
• Fixed issue 502 - some ADC/RTC pins for esp32c5 and esp32c6 had mapping errors
• Fixed async SPI transactions occasionally hanging forever on multi-core chips
• SPI: SpiBusDriver::new no longer leaves the device attached to the bus when acquiring the bus lock fails. The device used to stay registered, so freeing the bus later failed with ESP_ERR_INVALID_STATE ("not all CSses freed") and panicked in SpiDriver's destructor

Added

• QueueSet2, QueueSet3, QueueSet4 for waiting on multiple heterogeneous queues
• Basic compatibility for ESP-IDF release 6.0.
• I2S Standard, PDM and TDM Mode Driver dynamic reconfiguration (change sample rate)
• Support ESP-IDF 6.1 DSI bus flags and continuous high-speed clock-lane configuration.

Breaking

• I2S: ClockSource::Apll and ClockSource::Xtal on esp32p4, where the XTAL is now the default for this chip
• Dropped support for RGB/BGR666 format on ESP-IDF 6.0.

[0.46.2] - 2026-03-10

Fixed

• Fix a bug where the GPIO module did not build for esp32c5
• Fix a bug where the LCD driver was not protected with the esp_lcd component

[0.46.1] - 2026-03-10

Fixed

• Fix several compilation issues with esp32p4 and esp32h2

[0.46.0] - 2026-03-09

Breaking

• MSRV raised to 1.79
• The Timer drivers are not available under ESP-IDF 6+. These need to be rewritten against their newer "gptimer" ESP-IDF C equivalents.
• (#529) Peripheral and PeripheralRef removed and replaced with a simple pattern similar to the esp-hal one.
  • Check #529 for details on that change
• The prelude module is removed. It was anyway only having a handful of types listed in it. And furthermore, there was no prelude module for esp-idf-svc.
• embassy-sync updated to V0.7
• Implement new pcnt API. The old API will be available through the pcnt-legacy feature.
• ThreadSpawnConfiguration::name changed from &'static [u8] to &'static core::ffi::CStr as it is actually a CStr
• The rmt module is now only exposed on chips that support the rmt feature
• The onewire code has been updated for 1.0.4 and the new rmt API
• Implement new gptimer API. The old API will be available through the timer-legacy feature.
• Update embedded-io, embedded-io-async, and heapless dependencies to their latest versions
• Raise Rust MSRV to 1.82

Deprecated

• DB_11 ADC attenuation in favor of DB_12 for ESP-IDF V5.0+
• The old pcnt API (only available with the pcnt-legacy feature).
• The old rmt API (only available with the rmt-legacy feature)
• The old gptimer API (only available with the timer-legacy feature)

Added

• Send for AsyncCanDriver
• DB_12 ADC attenuation
• fade_with_time, fade_with_step, fade_stop for LedcDriver
• write_with_break for UartDriver and UartTxDriver
• New RMT API
• New GPTimer API
• esp32p4 pins and core command added.
• Support for esp32c5 and esp32c61
• Made the modem peripheral for esp32p4 dependent on esp_wifi_remote
• LDO support for esp32p4
• Support for PLL_F48M UART clock source on ESP32-H2
• LCD driver support; DSI peripheral support with the LCD driver for esp32p4
• New Deep and Light Sleep API (#555)

Fixed

• Fix pcnt_rotary_encoder example for esp32
• Fix the SDMMC driver for ESP-IDF V5.5+
• Fix UART initialization panic on ESP32-H2 with ESP-IDF 5.x due to unsupported PLL_F48M clock source
• Replace Arc with Rc in ledc_threads example (#514)
• Fix outdated task docs
• CAN: fix wrong Alert enum indexing / remove wrong TryFromPrimitive derive (#532)
• GPIO: Allow interoperability with other code that initializes the GPIO ISR service (#537)
• SD card support is no longer behind the experimental feature
• Added 6th TX channel config argument for IDF 5.5.2+.
• esp32p4 uses vPortExitCriticalMultiCore instead of vPortExitCritical
• UART: Fix dangling driver state when initialization fails mid-way

[0.45.2] - 2025-01-15

Fixed

• Fix ledc example (#511)
• Fix missing sdspi_host_get_dma_info for sdcard driver bug (#509)

[0.45.1] - 2025-01-10

Fixed

• Fix RGB to u32 conversion order in rmt_neopixel example (#505)
• Fix missing sdmmc_host_get_dma_info for sdcard driver bug (#507)

[0.45.0] - 2025-01-02

Deprecated

Breaking

• Make the UART config to ESP-IDF C config reusable outside the UART driver (for OpenThread)
• Re-use the SPI config struct of the SPI driver (for OpenThread)
• Add a usb_serial peripheral to the Peripherals struct for MCUs that do support the USB-serial-jtag peripheral (#503)
• UART default baud rate changed from 19'200 to 115'200

Added

• Compatibility with ESP-IDF v5.3.X
• Docs: Add some docstrings for ADC module. (#455)
• Update uart.rs, add rs485 half duplex (#456)
• Update spi.rs, fix half3wire read (#459)
• SPI: Mark DMA as supported in the docu
• SD Card driver; SD Card host drivers (SPI and SDMMC) (#457)
• RMT Onewire Peripheral (#454)
• Add an example of using interrupt directly without async (#474)
• Add support for ESP internal temperature sensor (#337)
• Support the thread modem peripheral on the c6 MCU
• Add dual and quad SPI support (#479)
• Initial USB-serial-jtag driver (#504)

Fixed

• Fix: UartDriver as embedded_io::Read blocks until buffer is full (#475)
• Allow modem splits even when only HW coex is used
• Fix esp_reset_reason_t constant names (#483)
• Fix drop for AdcDriver in deregister event callbacks (#487)
• Typo fix in task docs (#489)
• Update spi.rs for correct label in gpio_cs capture (#492)
• Fix a crash when dropping SpiDriver

[0.44.1] - 2024-07-09

Fixed

• The crate now does build with ESP-IDF V4.4.x + esp32c2/esp32c6/esp32h2, yet these MCUs should only be used with ESP-IDF V5+ as they are not officially supported with ESP-IDF V4.4.x (#450)
• Enum ResetReason not dealing with all reset reasons (panics on unknown reset reason) (#443, #444)

[0.44.0] - 2024-06-23

Deprecated

ESP-IDF v4.4 Please start upgrading to ESP-IDF v5.

Breaking

• removed: ESP-IDF v4.3 support, including mostly conditional compilations. (#420)
• GPIO20 is now included on esp32. Notice that not every esp32 has a physical GPIO20. (#370)
• ledc: now it can also be used with high_speed channels on esp32. (#424)
• dependency: updated embassy-sync to 0.6. (#437)
• adc: legacy adc driver is now behind a feature flag adc-oneshot-legacy starting with >= ESP-IDF v5.0. For justification, look at espressif/esp-idf#13938. (#433)
• spi: cs_pre/post_trans_delay() config option included. (#266)

Added

• rmt: Symbol now derives Clone and Copy (#386)
• reset: restart() function (#383)
• pcnt: Can now be used with esp32c6. (#407)
• can: Frame flags enum (#411)
• task: added MallocCap enum - Flag to indicate the capabilities of a Memory Region. (#419)
• i2s: new I2sDriver implementation allowing for splited bidirectional i2s. (#435)
• spi: added new_without_sclk SpiDriver constructor (#440)

Fixed

• esp32h2 builds: added missing hys_ctrl_mode field (#387)
• rmt: FixedLengthSignal was broken, which led to failures in the neopixel/smartled examples, among other things. (#402)
• e-hal 0.2: implements DelayUs and DelayMs for u8 to be consistent with the other implementations (#414)
• i2c: wrong timeout calculations. (#415)
• task: Compatibility with ESP-iDF v5.3 (pre-release) - adding stack_alloc_caps to ThreadSpawnConfiguration. (#419)
• i2s: Compatibility with ESP-IDF v5.3 (pre-release) - small internal adjustments to i2s (#419)
• ledc: max_duty() method miscalulated in certain conditions. (#431)
• timer: fix clock usage in timer driver used with ESP-IDF v5.x (#441)
• i2c: use correct xtal for esp32c2 on timeout calculations. (#438)

[0.43.1] - 2024-02-21

• Fix - PinDriver state changes and the drop call invoked pull-ups to be enabled. New default behavior on init / state transition / drop is to not enable pull-ups. (#344). If users want to reduce power usage on unused pins, they now need to manually enable pull-ups on a pin. For example, call core::mem::forget on the PinDriver instance after setting the pull-ups.
• #354 - breaking change - rmt driver now does not directly expose rmt_item32_t but rather - wraps it with a Symbol newtype
• #374 - Improve delay/timer errors and rounding calculations
• #379 - Remove 4096 limit for SPI dma transfer size
• Fix clippy duplicate imports warnings with latest 1.78 nightly

[0.43.0] - 2024-01-26

• Breaking change: feature riscv-ulp-hal (and consequently, feature esp-idf-sys) is now removed. Use the esp-ulp-riscv-hal crate instead
• MSRV 1.75; remove the nightly feature flag from all async trait implementations
• Update public dependencies e-hal to 1.0.0 and embassy-sync to 0.5 and private dependency heapless to 0.8
• Allow cargo check --all-features to work correctly (there used to be a build error when both the esp-idf-sys and the riscv-ulp-hal features were enabled)
• #365 - Async Uart driver is not Send
• #362 - Async Uart write hangs forever
• #353 - Use the PLL_F80M clock source with ESP IDF 5.1 and esp32c6
• #351 - Remove the OutputPin requirement from SPI SDI pin
• #350 - Not checking for ESP_FAIL in AsyncCanDriver::transmit

[0.42.5] - 2023-11-12

• BREAKING CHANGE IN A PATCH RELEASE DUE TO DISCOVERED UB: The subscribe methods in drivers PinDriver, PcntDriver and TimerDriver no longer accept non-static callbacks, as these lead to UB / crash when the driver is forgotten with e.g. core::mem::forget. Since local borrows are a very useful feature however, these are still allowed via the newly-introduced and even more unsafe subscribe_nonstatic method.

[0.42.4] - 2023-11-02

• Remove dependency on AtomicU64 which is no longer supported by the upstream *-espidf targets
• Fix some Clippy warnings in the spi driver

[0.42.3] - 2023-10-29

• Fix Timer array index bug #331 - prevented the use of TIMER10 on devices that support only 2 Timers
• Fix wrong TIMER11 index definition that declared TIMER11 as TIMER10 #331

[0.42.2] - 2023-10-28

• Support for latest ESP IDF 5.2 dev (master)

[0.42.1] - 2023-10-18

• Fix ambiguous name error #325 - a compilation issue when the NimBLE component is enabled in esp-idf-sys
• Fix compilation issues of the I2S driver for esp32h2 and esp32c2
• Fix compilation issues of the ADC drivers when the ESP IDF esp_adc component is not enabled
• Fix compilation issues of the GPIO driver for esp32c6

[0.42.0] - 2023-10-17

• MSRV raised to 1.71
• New driver: I2S
• New driver: continuous ADC
• New driver: snapshot ADC, implementing the new ESP-IDF 5.0+ snapshot ADC API
• Async support in the following drivers: Timer, SPI, I2S, continuous ADC, CAN (via an AsyncCanDriver wrapper), UART (via an AsyncUartDriver wrapper)
• All async drivers can now work out of the box with any executor (edge-executor no longer a necessity) via a new ISR-to-task bridge (esp_idf_hal::interrupt::asynch::IsrReactor)
• CAN driver: support for pulling alerts in blocking and async mode
• UART driver: support for pulling UART events
• GPIO driver: scoped callback; subscribe callback now needs to live only as long as the PinDriver instance
• Timer driver: scoped callback; subscribe callback now needs to live only as long as the TimerDriver instance
• task and interrupt modules: new submodule in each - asynch - featuring a signal/notification-like synchronization primitive
• task module: block_on method capable of executing a future on the current thread
• task module: new sub-module - queue for the FreeRTOS queue synchonization primitive
• task module: new sub-module - notification - a more ergonomic API around the FreeRTOS task notification API which was already exposed via the task::notify and task::wait_notification APIs
• Upgraded to embedded-hal 1.0.0-rc.1 and embedded-hal-async 1.0.0-rc.1
• Dependency esp-idf-sys now re-exported as esp_idf_hal::sys
• Breaking change: Peripherals::take now returns an error when the peripherals are already taken
• Breaking change: delay::Delay struct extended with configurable threshold
• Breaking change: task::wait_any_notification removed; task::notify renamed to task::notify_and_yield; new function - task::notify - that notifies a task without automatically yielding to the notified task if it is a higher priority than the currently interrupted one
• Breaking change: task::notify* and task::wait now take/return NonZeroU32 instead of u32
• Breaking change: GPIO - interrupts are now disabled automatically each time an ISR is triggered so as to avoid the IWDT triggering on level interrupts; use has to re-enable - in non-ISR code - via PinDriver::enable_interrupt()
• Breaking change: ESP IDF support for edge-executor moved to the edge-executor crate
• Deprecated: Using ESP-IDF 4.3 is now deprecated and all special cfg flags will be removed in the next release

[0.41.2] - 2023-06-21

• Do not set the single shot flag in the CAN frame (#263)
• Add safe abstractions to CRC functions in ESP ROM (#261)
• Use same error for all e-hal 0.2 trait impls (#260)
• Add support for WakeupReason from Ext0 events (#259)
• Compilation failed when ESP_IDF_VERSION = "release/v5.1" (#258)
• Fix UART docs (#252)

[0.41.1] - 2023-05-21

• UART driver was broken - see #250 for more details
• Removed a forgotten [patch.crates-io] section that was using esp-idf-sys from master (low impact, only relevant when building the examples)
• Clippy fixes

[0.41.0] - 2023-05-13 (Yanked due to #250, see above)

• MSRV 1.66 (but MSRV 1.70 necessary if nightly is enabled)
• Support for new chips: esp32c2, esp32h2, esp32c6 and future proofed for esp32c5 and esp32p4
• Support for ESP IDF 5.0, 5.1 and 5.2 (master)
• Support for embedded-hal 1.0-alpha.10 and embedded-hal-async 0.2.0-alpha.2 (API breakage in i2c and spi)
• Async GPIO native API with support for embedded-hal-async
• PCNT driver
• Alerts and Mode support in the TWAI driver
• Task Watchdog API
• Configurable interrupt levels in all drivers (minor API breakage in SpiDriver)
• EspError::from_infallible
• Auto-reload support in the timer driver

[0.40.1] - 2022-12-13

Fix the build when the ULP peripheral is enabled.

[0.40] - 2022-12-09

Rebase on top of esp-idf-sys 0.32:

• Retire any usages of esp-idf-sys::c_types in favor of core::ffi
• Remove casts from usize to u32 and back now that esp-idf-sys is compiled with --size_t-is-usize enabled

[0.39.3, 0.39.4] - 2022-12-09

Minor doc fixes; Clippy fixes; CriticalSection will panic on FreeRTOS mutex lock/unlock failures.

[0.39.1, 0.39.2] - 2022-11-21

Patch releases to fix compilation errors under no_std.

[0.39] - 2022-11-01

Release 0.39 is a backwards-incompatible release where almost all drivers were touched in one way or another.

Major Changes

The main themes of the 0.39 release are:

• Restore drop semantics for all drivers
• Simpler driver types (little to no generics)
• Unified naming
• Public API
• Completely revamped GPIO metaphor
• Timer driver
• Support for the critical-section crate by providing a CriticalSection implementation
• Support for the embassy-sync crate by providing two types of raw mutexes
• Support for the edge-executor crate
• Modem and Mac peripherals
• SPI driver rework

Major changes elaboration

Restore drop semantics for all drivers

• The release() method is now retired everywhere
• Just dropping a driver will make it stop functioning
• If peripherals need to be reused after the driver is dropped, this is achieved by passing the peripherals to the driver constructor via &mut references, e.g. I2cMasterDriver::new(&mut peripherals.i2c1, &mut peripherals.pins.gpio10, &mut peripherals.pins.gpio11, &mut peripherals.pins.gpio12)

Simpler driver types

• All peripheral generics are removed from all drivers' types; e.g., the I2C master driver now has the following type signature: I2cMasterDriver<'d>
• The lifetime - 'd from above designates the lifetime of the peripheral (e.g. I2c) that is used by the driver
• In the most common case where the peripheral is just moved into the driver (and no longer accessible when the driver is dropped), 'd = 'static, or in other words, the type signature of the driver becomes I2cMasterDriver<'static> and can even be type aliased by the user as in pub type SimpleI2cMasterDriver = I2cMasterDriver<'static>;
• When the peripherals are passed to the driver using &mut references, 'd designates the lifetime of the &mut reference
• Note that the constructor of each driver is still generic by the peripherals it takes, but these generics are "erased" from the type of the driver once the driver is constructed, as we only need to "remember" whether the peripheral is moved into the driver, or used via a &mut reference and can be reused after the driver is dropped. This semantics is captured by the 'd lifetime

Unified naming

• Each driver is named <Peripheral>Driver, where <Peripheral> is the name of the peripheral. E.g. the driver for the Uart peripheral is named UartDriver, the driver for the Adc peripheral is named AdcDriver and so on
• The one exception is the GPIO subsystem, where the driver is not named GpioDriver, but the simpler PinDriver instead, even if the concrete peripheral struct type might be e.g. Gpio12
• In case there are multiple drivers per peripheral - as in - say - a master and a slave protocol driver - only the Slave contains itself in its name, as in e.g. SpiDriver and SpiSlaveDriver
• NOTE: We are NOT fond of still using offensive terms like "master" and "slave". Unfortunately, the embedded industry itself has not yet agreed (to our knowledge) on a good replacement for these terms, hence they are still around

Public API

In addition to implementing the embedded-hal traits where possible, all drivers now have public API. While the public API loosely follows the APIs from embedded-hal, it deviates where appropriate so that the native underlying ESP IDF driver is better utilized.

These public APIs mean that the user is no longer required to depend on the embedded-hal crate so as to consume the esp-idf-hal drivers. Consuming the drivers via the embedded-hal traits is now only necessary when the user is targetting cross-platform portability of their application code.

Completely revamped GPIO metaphor

In previous releases, the GPIO driver was a bit different from the others, in that each pin peripheral itself used to have TypeState and methods that configured the peripheral into a certain mode (as in e.g. input-only, input-output, output-only, ADC and so on) that drived the peripheral through a type-state change.

Furthermore, there was no notion of a pin "driver". The driver methods were fused directly into the peripheral, and a subset of these methods were available, depending on the type-state of the peripheral.

This scheme was asymmetric with the rest of the HAL, where peripherals are mostly opaque singleton objects, and it is the driver that exposes a user visible API (including implementation of the corresponding embedded-hal traits). It also suffered from less flexibility and code duplication accross the regular GPIO pins, and their degraded Any*Pin variants.

The new GPIO subsystem follows the driver-peripheral separation metaphor like everything else:

• Pin peripherals are static objects with no type-state, where the only allowed operation is to degrade a concrete pin instance implementing the Pin / InputPin / OutputPin traits into a corresponding Any*Pin struct which is useful when e.g. passing an array of input or output pins accross the application code, as generics are erased by the degrading operation
• The capabilities of a pin peripheral are expressed by the concrete pin struct type (i.e. GpioXX) implementing a set of traits (InputPin, AnalogPin) and so on
• PinDriver is the universal driver for any pin peripheral (e.g. be it a non-degraded GpioXX struct, or a degraded AnyIOPin, AnyOutputPin or AnyInput pin struct)
• Providing an ISR handler is possible - via PinDriver - on any input pin, including on a degraded one

Finally, PinDriver can now work with digital pins by using the RTC digital IO API on chips that support this (ESP32 and the ESP32 S* series)

Timer driver

The new timer module is exposing the hardware timer peripherals on the esp32* MCUs via the ESP-IDF timer driver. Just like the underlying ESP-IDF timer driver, a lot (but not all) methods are actually safe to call from an ISR routine. Those which are unsafe will panic immediately if called from an ISR.

Support for the critical-section crate

In addition to implementing embedded-hal crates, esp-idf-hal integrates with the wider Rust embedded ecosystem by providing out of the box critical section implementation for the critical-section crate.

To enable this support, you need to compile the crate with the critical-section feature enabled.

Note that the provided critical section implementation is based on esp_idf_hal::task::CriticalSection, which itself is based on a recursive FreeRtos mutex. This means that you can enter() the critical section for long periods of time, and your code can still be preempted by ISR routines or high priority FreeRtos tasks (threads), thus you should not worry about slowing down the whole RTOS reaction times by using a critical section. This also means however, that this critical section (and its native esp_idf_hal::task::CriticalSection equivalent) CANNOT be used from an ISR context.

If you need a critical section with a warranty that your code will not be interrupted by an ISR or higher priority tasks (i.e. working accross ISRs and tasks), you should be using esp_idf_hal::interrupt::IsrCriticalSection instance, or the esp_idf_hal::interrupt::free method. Keep in mind that you should stay in this type of critical section for a very short period of time, because it disables all interrupts.

Support for the embassy-sync crate

The HAL provides two mutex implementations that implement the RawMutex trait from the embassy-sync crate thus integrating the ESP-RS ecosystem better with the Rust embedded async ecosystem:

• EspRawMutex - this implementation uses a FreeRtos mutex and behaves similarly to esp_idf_hal::task::CriticalSection
• IsrRawMutex - this implementation works by disabling all interrupts and thus behaves similarly to esp_idf_hal::interrupt::IsrCriticalSection

To enable this support, you need to compile the crate with the embassy-sync feature enabled.

While embassy-sync itself can use - via its CriticalSectionRawMutex mutex bridge - whatever a HAL is providing as a critical section to the critical-section crate, the above two implementations provide further benefits:

• EspRawMutex is almost the same as the embassy-sync native CriticalSectionRawMutex with the one major difference that ALL CriticalSectionRawMutex instances in fact share a single RTOS mutex underneath. This is a limitation which is coming from the critical-section crate itself. In contrast, each EspRawMutex instance has its own separate RTOS mutex
• IsrRawMutex - as the name suggests - allows embassy-sync to be utilized in scenarios where the application code should synchronize accross ISRs and regular RTOS task based code

Support for the edge-executor crate

This is another HAL feature that integrates the ESP-RS ecosystem with the Rust embedded async ecosystem.

The edge-executor crate is a simple local-only executor that is based on the popular async-task crate coming from the Smol async executor (which in turn powers the async-std executor). Without getting into too many details, edge-executor is useful in embedded cotexts because

• It is no_std compatible (but requires an allocator, unlike embassy-executor, so the latter might be a better fit for bare-metal use cases where ESP IDF is not utilized)
• Has a small footprint
• Is ISR-friendly in that it can operate from an ISR context - or - which would be the natural setup when used on top of a RTOS like ESP IDF's FreeRtos - can be awoken directly from an ISR routine, this having a minimal latency

To enable this support, you need to compile the crate with the edge-executor feature enabled.

The support for edge-executor in esp-idf-hal is in terms of providing an ISR-friendly Monitor trait implementation for edge-executor - FreeRtosMonitor - that can be awoken directly from an ISR, and is based on the FreeRtos task notification mechanism which is exposed in the esp_idf_hal::task crate.

Modem and Mac peripherals

In previous releases, the Wifi and Ethernet drivers (part of the esp-idf-svc crate) did not follow the philosophy of esp-idf-hal in that each driver should take a corresponding peripheral (by moving or by a &mut reference).

This is now addressed in that the esp-idf-hal crate models two new peripherals:

• modem::Modem: models the esp32* hardware modem peripheral and implements two new marker traits: modem::WifiModemPeripheral and modem::BluetoothModemPeripheral
  • By implementing both of the above traits, the modem::Modem peripheral should be usable by both the Wifi driver in esp-idf-svc, as well as the future Bluetooth driver
  • modem::Modem is splittable into two other peripherals: modem::WifiModem (implementing only the modem::WifiModemPeripheral trait) and modem::BluetoothModem (implementing only the modem::BluetoothModemPeripheral trait) so that in future the simultaneous operation of the Wifi and Bluetooth drivers to be possible
• mac::MAC: models the EMAC hardware available on the original ESP32 chip. The Ethernet driver implementation - just like the Wifi driver implementation - is still in the esp-idf-svc crate which better aligns with the underlying ESP-IDF implementations, yet the new Wifi and Ethernet drivers in esp-idf-svc now expect their corresponding peripherals to be supplied during construction time

SPI driver rework

The SPI driver is now split into two structures

• SpiDriver - represents an initialized SPI bus and manages access to the underlying SPI hardware
• SpiDeviceDriver (new) - an abstraction for rach device connected to the SPI bus

The above split allows for the creation of more than one device per SPI bus. (Up to 6 for the esp32c* variants and 3 for all others). When creating an SpiDeviceDriver instance, user is required to provide a Borrow to the SpiDriver instance (as in SpiDriver, &SpiDriver, &mut SpiDriver, Rc(SpiDriver) or Arc(SpiDriver)), so that the SPI bus stays initialized throughout the liftime of all devices.

A second wrapper implementation is now also provided: SpiSoftCsDeviceDriver It allows for more devices per SPI bus (i.e. above the 3/6 limit). This is implemented by operating the CS pin in software mode.