MicroPython Files

This release of MicroPython sees machine.PWM support finally added to the stm32 port, as well as the alif port. This rounds out PWM support to all Tier 1 and Tier 2 microcontroller-based ports, making it easy to create and control PWM outputs in a consistent way.

A new machine.CAN class that has been in development for a couple of years has now been finalised in this release, with added documentation, a common set of bindings, comprehensive tests, and an implementation for the stm32 port. This is a big step forward for a consistent way to use CAN across all of the ports, and implementations for other ports will follow soon.

This release also sees the addition of template strings as per PEP 750 https://peps.python.org/pep-0750/. Template strings (or t-strings) are similar to f-strings, allowing expressions within the string literal. But unlike f-strings, t-strings do not concatenate the pieces of the literal, rather they remain as separate components within a Template object. MicroPython's t-strings match CPython almost exactly, except for a few minor differences (the a/ascii conversion specifier and space after a conversion specifier are not supported). Template strings are enabled at the "full feature" level, which includes the alif, mimxrt, samd (SAMD51 only) and webassembly (pyscript variant) ports.

The t-string parsing code is an extension of the existing f-string parser, and in order to support nested t-string, f-strings now also support nested f-strings: f-strings within expressions within f-string literals.

Another Python feature added in this release is the weakref module with weakref.ref and weakref.finalize classes. These classes allow registering a callback to be called when an object is reclaimed by the garbage collector. The semantics of this follow very closely the weakref semantics in CPython (except for the fact that MicroPython does not use reference counting). Due to the memory and garbage collector overhead, this module is currently only enabled on the webassembly pyscript variant, although it can be manually enabled on any port if needed.

An outline of MicroPython's design values has been added to the main README. This aims to put into words some of the more intangible aspects of the project, in the hope that it will help strengthen and maintain those values moving forward. All MicroPython users and developers are encouraged to read these values, which can be found at https://github.com/micropython/micropython/blob/master/README.md#micropython-design-values

In the native emitter component, the RISC-V 32-bit emitter has a new architecture flag "zcmp" which can be enabled for RV32 targets that support compressed instructions. When this flag is enabled, Zcmp opcodes are used for function prologues and epilogues. There have also been some optimisations to generated native code, as well as added support for inline Xtensa assembler on windowed cores (like the esp32). Furthermore, it's now possible to configure MicroPython (at build time) to be able to load native code from .mpy files without having the native emitter enabled.

As usual, work has continued on the test suite, making it more robust to target failures, better able to skip tests that can't run on a target, and run consistently across a broader range of targets. All these things help maintain the high quality of the MicroPython code base.

ROM filesystem support and the VfsRom class have been enabled on a few more ports, namely: mimxrt, nrf, renesas-ra and samd (both SAMD21 and SAMD51).

The alif port sees the alif_ensemble-cmsis-dfp library updated to v1.3.4, support to put external flash to sleep, and improved support for deepsleep power saving modes, with wake-up from deepsleep via a falling GPIO or RTC alarm (the latter is available by the standard timeout_ms argument to machine.deepsleep()). As mentioned above, this port now has PWM support via the standard machine.PWM interface, and provides the freq(), duty_u16() and duty_ns() methods as well as the invert keyword argument in the PWM constructor. There are 11 independent timers with 22 PWM outputs.

The esp32 port adds a new LDO driver, and enables Zcmp opcodes, both for ESP32-P4 SoCs. os.dupterm() reading has been improved (it's no longer necessary to call os.dupterm_notify()) and various bugs have been fixed. Support for ESP-IDF from v5.3 and up to v5.5.1 has been consolidated, and support for IDF below v5.3 has now been dropped.

The mimxrt port now implements the standard machine.Counter and machine.Encoder classes, and adds a few new features such as: min/max counter values, index, reset and match pins, support for cycle counting and support for IRQ callbacks. The general documentation and mimxrt quick reference has been updated to describe these additions. This port has also updated the nxp_driver SDK to MCUX_2.16.100, added PSRAM support, added support for DP83867 PHY Ethernet, and increased the resolution of the RTC from 1 second to 1/32768 seconds.

The rp2 port has updated pico-sdk to its 2.2.0 release, and as part of this switched all RNG sources from ROSC to the new pico_rand component. This port has also enabled Zcmp opcodes for RP2350 in RV32 mode.

As mentioned above, the stm32 port now has the standard machine.PWM class available, which works across all 14 MCU families supported by this port. The freq(), duty_u16() and duty_ns() methods are available, as well as output inversion. A heuristic is used to statically assign a TIM and channel to each pin that can support PWM, and the heuristic is chosen to maximise the number of independent PWM outputs. The new machine.CAN implementation is available on MCUs with either a bxCAN or FD-CAN peripheral, although flexible data-rates are not yet supported.

New boards added in this release are:

• esp32 port: SPARKFUN_THINGPLUS_ESP32C5 and SEEED_XIAO_ESP32C6;
• mimxrt port: PHYBOARD_RT1170;
• rp2 port: CYTRON_NANOXRP_CONTROLLER, CYTRON_MOTION_2350_PRO, WAVESHARE_RP2350B_CORE, WAVESHARE_RP2040_LCD_0_96, WAVESHARE_RP2040_PLUS, WAVESHARE_RP2040_ZERO and SEEED_XIAO_RP2040;
• stm32 port: NUCLEO_H753ZI and WEACTSTUDIO_MINI_STM32U585.

The change in code size since the previous release for select builds of various ports is (absolute and percentage change in the text section):

   bare-arm:    -52  -0.092%
minimal x86:   -321  -0.173%
   unix x64:   -104  -0.012%  (standard variant)
      stm32:  +7028  +1.782%  (PYBV10 board)
      esp32:   +844  +0.048%  (ESP32_GENERIC board)
     mimxrt: +10072  +2.685%  (TEENSY40 board)
 renesas-ra:  +1816  +0.289%  (EK_RA6M2 board)
        nrf:  +1788  +0.947%  (PCA10040 board)
        rp2:   +356  +0.104%  (RPI_PICO board)
        rp2:  -1552  -0.172%  (RPI_PICO2_W board)
       samd:  +3492  +1.288%  (ADAFRUIT_ITSYBITSY_M4_EXPRESS board)

The leading causes of these changes in code size are:

• bare-arm, minimal x86, unix x64: make some tuple and list helper- functions inline
• stm32: add new machine.PWM and machine.CAN classes
• esp32: use detailed error strings for TLS sockets, various small port-specific fixes
• mimxrt: support for VfsRom filesystem, support for t-strings, add new machine.Counter and machine.Encoder classes
• renesas-ra: support for VfsRom filesystem
• nrf: support for VfsRom filesystem
• rp2: switch RNG source to pico_rand, reduce footprint of pin structures
• samd: support for VfsRom filesystem, support for t-strings

Thanks to everyone who contributed to this release: Alessandro Gatti, Algy Tynan, Alon Bar-Lev, Andrew Leech, Angus Gratton, Anson Mansfield, Antonio Galea, Artem Makarov, Chris Webb, Damien George, Daniël van de Giessen, Didier C, Dryw Wade, Elvis Pfutzenreuter, EngWill, FH, Fin Maaß, iabdalkader, Jack Whitham, Jacob Williams, Jeff Epler, jetpax, Jos Verlinde, Koudai Aono, Kwabena W. Agyeman, Matt Trentini, Matthias Urlichs, mdaeron, Michel Le Bihan, Ned Konz, Oliver Joos, Paul Grayson, Peter Harper, Phil Howard, robert-hh, stijn, sync-on-luma, Thomas Kiss, Thomas Propst, Yuuki NAGAO.

MicroPython is a global Open Source project, and contributions were made from the following timezones: -0800, -0700, -0600, -0500, -0400, -0300, +0000, +0100, +0200, +0300, +0800, +0900, +1000, +1100.

The work done in this release was funded in part through GitHub Sponsors, and in part by George Robotics, Espressif, Arduino, OpenMV, and Planet Innovation.

What follows is a detailed list of changes, generated from the git commit history, and organised into sections.

Main components

all:

• fix spelling of Micropython -> MicroPython
• use enum instead of bool argument to mp_handle_pending
• remove warning about the project being in beta stage
• add a section describing MicroPython's values

py core:

• misc: remove unused mp_check function
• emitnative: optimise register clearing
• asmrv32: reserve a flag for the Zcmp RV32 CPU extension
• asmrv32: use Zcmp opcodes for function prologues and epilogues
• persistentcode: decouple native code loading from emitters' presence
• persistentcode: detect the target architecture from compiler defines
• emitglue: flush caches when loading native code without emitters
• misc: add byte-swapping macros
• emitglue: check for bytecode with MICROPY_PY_FUNCTION_ATTRS_CODE
• mpconfig: enable MICROPY_PY_FUNCTION_ATTRS_CODE when marshal enabled
• persistentcode: support saving functions with children
• objfun: support code on functions with children
• vstr: make vstr_ins_byte/char functions inline to reduce code size
• vstr: add vstr_ins_strn helper function
• vstr: don't check for byte_len>0 in vstr_ins_blank_bytes
• lexer: use null char as lexer EOF sentinel
• lexer: add support for nested f-strings within f-strings
• lexer: move f-string completion code to more logical location
• runtime: make import-all support non-modules via dict/all
• runtime: reorder mp_handle_pending_behaviour_t enum
• runtime: rename mp_handle_pending_internal to mp_handle_pending
• misc: remove unused CHECKBUF macros
• objmodule: move decl of mp_obj_module_get_globals to objmodule.h
• objfun: move decl of mp_obj_fun_get_name to objfun.h
• objfun: rename mp_obj_fun_get_name to mp_obj_fun_bc_get_name
• objlist: move all list helper declarations to objlist.h
• objlist: make three list helper functions inline
• objtuple: move all tuple helper declarations to objtuple.h
• objtuple: make mp_obj_tuple_get an inline function
• emitinlinextensa: refactor handling of selected opcodes
• objarray: avoid double zero init on sized bytearrays
• objstr: avoid double zero init on sized bytes
• stream: use detailed error strings for TLS sockets
• objzip: adjust zip iter code to not use mp_obj_tuple_del
• objtuple: remove unused mp_obj_tulpe_del function
• gc: trace all marked heads in debug log
• gc: differentiate between root and subtree pointers for debug log
• misc: fix truncating cast to char
• emitinlinextensa: add inline assembler support for windowed cores
• emitinlinextensa: refactor handling of selected narrow opcodes
• asmthumb: do not clobber index register on viper load/store
• asmrv32: do not clobber index register on viper load/store
• objtype: expose mp_native_base_init_wrapper_obj
• objexcept: check for incompletely constructed exceptions
• objstr: factor code with a helper function to create empty str/bytes
• objstr: fix b"".hex() so it returns an empty str object
• lexer: fix parsing of f'{{'
• add support for PEP 750's t-strings
• objlist: add helpers for creating/ensuring list args
• objtemplate: correctly cast qstr literals when printing
• modweakref: implement weakref module with ref and finalize classes
• emitglue: fix macro logic that selects cache flushing code

extmod:

• modopenamp: rework trace buffer setup procedure
• modselect: handle pending events before entering poll
• modlwip: fix latent bug with partially created socket object
• modlwip: adjust logic for determining a listening socket
• modlwip: narrow error_lookup_table type to int8_t
• modlwip: keep TCP data on remote RST
• modmarshal: support marshal.dumps of functions with children
• ensure stream ioctl's are a no-op for unknown requests
• modlwip: always set the lwip_socket_ioctl() return value
• vfs_reader: process pending events during file reads
• modos: raise an error at a negative argument of os.urandom()
• mbedtls: factor out mbedtls_hardware_poll() to common code
• keep LWIP timer running if lwip poll_sockets() is called
• add generic machine.CAN helpers & docs
• machine_pwm: fix use of object when pointer is needed
• nimble/modbluetooth_nimble: handle port init failures
• modlwip: ensure socket is finalisable if error during creation
• modlwip: call user callback on newly-received UDP or RAW packet

shared:

• readline: handle \r and \n correctly as a newline

drivers: no changes specific to this component/port

mpy-cross:

• mpconfigport: explicitly disable native code loading
• enable t-strings

lib:

• nxp_driver: update mimxrt SDK to MCUX_2.16.100
• pico-sdk: update pico-sdk to 2.2.0 release
• libhydrogen: update to latest release
• alif_ensemble-cmsis-dfp: update to v1.3.4
• micropython-lib: update submodule to latest
• cyw43-driver: update driver to latest version v1.1.1

Support components

docs:

• library/network.WLAN: fix typo for ESP32 protocol constants
• library: document that sleep(0)/sleep_ms(0) run the scheduler
• mimxrt: add docs for mimxrt.Flash
• library/network.PPP: document the optional poll() argument
• develop/writingtests: document parameters of run_test.py
• add documentation for the mimxrt Encoder/Counter class
• library: document string.templatelib module
• esp32: replace 'esptool.py' by 'esptool' in command line example
• library/re: document non-capturing grouping
• add generic machine.CAN helpers & docs
• library/machine.PWM: add alif,stm32 to list of ports with invert
• library/machine.PWM: document hardware PWM layout
• update copyright year range to include 2026
• reference/speed_python: update native emitter limitations
• library/weakref: add documentation for weakref module

examples: no changes specific to this component/port

tests:

• ports/esp32/check_err_str.py: preallocate global variable
• basics/string_fstring.py: test fstring nested replacement fields
• run-tests.py: skip list sort stress test for ESP8266
• extmod/vfs_blockdev_invalid.py: handle low memory conditions
• target_wiring: provide an ESP8266 target wiring module
• run-tests.py: discover RV32 extension inlineasm tests
• run-natmodtests.py: explicitly open prelude file
• basics/try_finally: fix try/finally flow tests under CPython 3.14
• float/math_fun: fix domain error tests with CPython 3.14
• float/complex1.py: fix CPython 3.14 deprecation
• run-tests.py: re-add stress_schedule.py for GitHub Actions
• thread/stress_schedule.py: decrease backoff time
• micropython: add new schedule_sleep.py test
• run-tests.py: re-enable some asyncio tests for the native emitter
• thread/stress_schedule.py: remove decorator/inaccurate comment
• multi_net/tcp_client_rst.py: improve and extend test
• factor out common helper functions to separate Python module
• multi_net: skip all ssl/tls tests on axTLS
• multi_net: use random.getrandbits instead of random.randrange
• extmod/machine_spi_rate.py: use target wiring for SPI instances
• target_wiring: add SPI instance for mimxrt, nrf, renesas-ra, samd
• target_wiring/README: add README describing target_wiring specs
• run-tests.py: exit with error code 2 if test runner fails
• test_utils.py: abort test if serial port fails at start
• run-tests.py: abort test run if enter_raw_repl fails many times
• run-tests.py: broaden the check for raw REPL failure
• micropython: add a test for checking viper value clobbering
• extmod/os_urandom.py: add test for os.urandom
• micropython: add a test for throwing incomplete exception
• cpydiff: add a section for throwing incomplete exceptions
• run-tests.py: add an argument for showing which tests would run
• run-tests.py: make skip logic work irregardless of test path
• run-tests.py: use normal discovery if tests dir passed explicitly
• cmdline: make tests succeed irregardless of invocation path
• run-tests.py: output consistent test file paths
• run-multitests.py: improve error handling for communication error
• net_inet: use the letsencrypt TLS root cert for all tests
• run-internalbench.py: add option for running against CPython
• extmod_hardware/machine_pwm.py: add alif pin config
• basics/builtin_str_hex.py: remove corresponding .exp file
• extmod_hardware/machine_encoder.py: add a MIMXRT configuration
• extmod_hardware/machine_encoder.py: separate the connection test
• extmod_hardware/machine_counter.py: separate the connection test
• add full feature and coverage tests for PEP 750 template strings
• run-tests.py: ignore known-flaky test failures
• ports/stm32/can: update pyb.CAN tests for FDCAN
• extmod_hardware/machine_pwm.py: round expected timing calculation
• extmod_hardware/machine_pwm.py: add pin settings for stm32 port
• extmod_hardware/machine_pwm.py: convert test to use target_wiring
• basics: add tests for weakref.ref and weakref.finalize
• basics: add test for weakref having exception in callback
• feature_check/tstring.py: remove check for string.templatelib

tools:

• mpy_ld.py: fix R_RISCV_GOT32_PCREL handling
• mpy_ld.py: fix handling of R_RISCV_TLSDESC_LOAD_LO12
• mpy_ld.py: add RV64 natmod support
• ci.sh: run natmod tests as part of CI for Unix/RV64
• ci.sh: put embedding build rules in ci.sh
• ci.sh: update Unix/MIPS target to Ubuntu 24.04 LTS
• ci.sh: update Unix/Arm target to Ubuntu 24.04 LTS
• ci.sh: use CPython 3.11 for Unix/RV64
• ci.sh: update Unix/x86 target to Ubuntu 24.04 LTS
• mpy_ld.py: optimise MPY trampoline sizes if possible
• mpy_ld.py: write architecture flags to output natmod if needed
• codeformat.py: use input files when formatting python code
• ci.sh: increase qemu_arm test run timeout

CI:

• workflows: bump actions/upload-artifact from 4 to 6
• workflows: bump actions/cache from 4 to 5
• workflows: introduce and use ci_esp32_idf_ver helper
• workflows: add esp32 to code size report
• workflows: use same Ubuntu for code_size as ports_esp32
• workflows: bump actions/cache from 4 to 5
• workflows: add check for misspelling of "MicroPython"
• install Python 3.11 for Windows CI runs
• workflows: bump actions/upload-artifact from 6 to 7
• add a Generative AI Usage declaration to the PR template
• revert "Run esp32&zephyr daily to keep mstr branch caches hot"
• build oldest & newest ESP-IDF versions in CI

The ports

all ports:

• remove incorrect and unnecessary mp_handle_pending declaration
• refactor os.urandom()
• don't pass -nostdlib in CFLAGS

alif port:

• Makefile: do not hardcode the python interpreter name
• Makefile: enable job server support on Ubuntu LTS
• ospi_flash: remove workaround for P10_7 OSPI pinmux issue
• boards/OPENMV_AE3: update romfs partition size
• boards/OPENMV_AE3: make JTAG pins controllable as GPIOs
• fix ALIF_TOOLS to use $(TOP) and remove unused ALIF_CONFIG
• modmachine: disable IRQs before going to sleep
• ospi_flash: add ospi_flash_sleep helper function
• boards/OPENMV_AE3: save power upon deepsleep
• boards/OPENMV_AE3: allow user button to wake from sleep
• boards/ALIF_ENSEMBLE: add all SW1 pins and enable pull-ups on them
• boards/ALIF_ENSEMBLE: add an off-profile
• machine_rtc: factor out RTC helper functions
• modmachine: implement timeout_ms argument to deepsleep
• boards/OPENMV_AE3: configure sensor interrupts as GPIO input
• machine_pwm: implement machine.PWM
• irq: add missing IRQ priorities

bare-arm port: no changes specific to this component/port

cc3200 port:

• mods/pybpin: reduce footprint of AF pin structures

embed port: no changes specific to this component/port

esp8266 port:

• boards/ESP8266_GENERIC: remove OTA board variant
• modesp: allocate executable memory when needed

esp32 port:

• boards/ESP32_GENERIC_S3: reinstate old FLASH_4M variant
• machine_sdcard: fix SDMMC slot assignment for non-default slots
• mpconfigport: enable Zcmp opcodes for ESP32P4
• machine_pin: rename legacy CONFIG_ESP32_SPIRAM_SUPPORT option
• machine_uart: change default UART(1) pins on ESP32 with SPIRAM
• esp32_rmt: update FIXME on RMT module
• modesp32: update available RTC pins for ESP32C6
• add LDO driver for ESP32-P4
• mphalport: actually read from dupterm in mp_hal_stdin_rx_chr()
• increase minimum CMake version to 3.16
• fix linker errors with CMake <3.25 and libbtree
• esp32_rmt: release GIL while waiting for TX done
• only check the lockfile currently used by the build
• drop support for ESP-IDF <v5.3
• fix build for ESP-IDF version 5.3
• add helpers for creating/ensuring list args
• build oldest & newest ESP-IDF versions in CI
• boards/SPARKFUN_THINGPLUS_ESP32C5: add SF Thing Plus ESP32-C5
• boards/SEEED_XIAO_ESP32C6: add new XIAO board definition
• esp32_common.cmake: add missing C flags to user C module sources

mimxrt port:

• add support for VfsRom filesystem
• pin: reduce footprint of pin structures
• machine_adc: initialize LPADC2 for rt117x
• machine_adc: support ADC channel groups on rt117x
• eth: add DP83867 PHY driver support
• boards/MIMXRT1170_EVK: remove obsolete pin defines
• eth: improve Dual Ethernet configuration
• add ALT11 pin mode support for MIMXRT1176
• increase resolution of RTC to 1/32768 seconds
• add PSRAM implementation
• Makefile: add CXXFLAGS, and libstdc++ to LDFLAGS
• machine_uart: use a wrapper function to handle IRQ idle support
• Makefile: make board linker scripts configurable
• boards/PHYBOARD_RT1170: add PHYBOARD-RT1170 board support
• boards/PHYBOARD_RT1170: update use of mp_handle_pending()
• implement Quadrature Encoder and Counter classes
• boards/make-pins.py: add the XBAR tag to the AF names
• boards: add missing declarations of XBARA1 for two boards
• boards/ADAFRUIT_METRO_M7: remove unused WiFi/BLE declarations
• machine_encoder: remove executable mode bit

minimal port: no changes specific to this component/port

nrf port:

• main: allocate executable memory when needed
• add support for VfsRom filesystem
• modules/machine/pin: reduce footprint of pin structures
• mpconfigport: remove duplicate help and open from builtins module

pic16bit port:

• mpconfigport: remove dummy builtins.open function

powerpc port:

• mpconfigport: remove dummy builtins.open function

qemu port:

• Makefile: allow usage of a custom QEMU binary to run code
• Makefile: allow overriding the test natmods list
• enable loading natmods on RV64
• mphalport: ensure mp_hal_delay_ms(0) handles pending tasks

renesas-ra port:

• add support for VfsRom filesystem
• pin: reduce footprint of pin structures
• boards/ARDUINO_PORTENTA_C33: increase TinyUSB queue size

rp2 port:

• mpconfigport: enable Zcmp opcodes for RP2350 in RV32 mode
• CMakeLists.txt: set the appropriate mpy-cross flags on all targets
• machine_pin: reduce footprint of pin structures
• add pico_platform_common to sdk components
• remove build patch for Findpioasm.cmake
• fix linker scripts to match SDK 2.2.0
• boards/POLOLU_ZUMO_2040_ROBOT: remove header file
• switch all RNG sources from ROSC to pico_rand
• keep LWIP timer running if lwip poll_sockets() is called
• modules/rp2.py: don't corrupt globals on asm_pio() exception
• boards/CYTRON_NANOXRP_CONTROLLER: add support for NanoXRP board
• boards/CYTRON_MOTION_2350_PRO: add Cytron Motion 2350 Pro board
• boards/WAVESHARE_RP2350B_CORE: add Waveshare RP2350B Core board
• boards/WAVESHARE_RP2040_LCD_0_96: add Waveshare RP2040 LCD 0.96
• boards/WAVESHARE_RP2040_PLUS: add Waveshare RP2040 Plus 4M and 16M
• boards/WAVESHARE_RP2040_ZERO: add Waveshare RP2040 Zero board
• rp2_dma: disable DMA IRQ before clearing handler function
• boards/SEEED_XIAO_RP2040: add XIAO RP2040 board definition

samd port:

• add support for VfsRom filesystem for SAMD21 and SAMD51
• pin_af: reduce footprint of pin structures
• boards: add more flash choices for Adafruit M4 boards

stm32 port:

• main: enable all AHB5 GRP1 clocks in low power mode
• sdcard: use high speed mode for SD transfers on H5/H7/N6
• add support for all STM32F412xx MCUs
• boards: add linker script for STMF412xE with 512k flash
• boards/NUCLEO_H753ZI: add NUCLEO_H753ZI board support
• boards/NUCLEO_H7x3: fix st-flash and add openocd configuration
• boards/NUCLEO_H7x3: add UART1, remove UART5, slow down PLL1Q
• default to --connect-under-reset if flashing via deploy-stlink
• convert port to use new event waiting functions
• boards: add UARTs to NUCLEO F746ZG and NUCLEO F439ZI
• update STM32U5 suppport
• boards: add WeAct STM32U585 board support
• boards/stm32l072xz.ld: correct comment in linker script
• pin: reduce footprint of pin structures
• support more stm32g4 variants
• pyb_can: fix initialising CAN2 clearing CAN1 filters
• can: clarify can_clearfilter() arguments
• expose FDCAN2 on board NUCLEO_G474RE
• add helpers for creating/ensuring list args
• add can_get_state() function, use from pyb.CAN
• implement index-aware STM32G4 FDCAN HAL TX functions
• add machine.CAN implementation
• fix printing value of pyb.CAN auto_restart on FDCAN hardware
• timer: use HAL macro to determine if TIM is 32-bit
• timer: expose functions to convert id to reg and enable TIM clock
• machine_pwm: implement machine.PWM class
• machine_pwm: use heuristic to assign TIMx_CHy to a pin
• boards: disable some features on boards with small flash
• boards/stm32f091_af.csv: split TIM2_CH1 from TIM2_ETR
• boards/stm32n657_af.csv: add TIM alt funcs to PA0-PA3
• mpthreadport: increase minimum thread stack size to 2.5k
• boards/PYBD_SF2: free up some space in internal flash

unix port:

• alloc: map executable memory for code loading when needed
• mpconfigport: enable natmod loading for RISC-V builds
• modtime: handle pending events during sleep(0)
• unix_mphal: ensure mp_hal_delay_ms handles pending tasks

webassembly port:

• convert port to use new event waiting functions
• Makefile: add test//% target
• variants/pyscript: enable weakref module and add tests

windows port:

• compile printf.c for the msvc port

zephyr port:

• Kconfig: resolve build problem with multiple FatFs libs
• main: put GC heap in noinit linker area
• modzsensor: add additional sensor type constants
• add support for RISC-V RV32IMC native code emitter
• mpconfigport: remove duplicate builtins.open definition
• use nodelabel when printing device name
• fix macro for getting erase_block_size