bf2005de9e
This commit lets mpy_ld.py resolve symbols not only from the object files involved in the linking process, or from compiler-supplied static libraries, but also from a list of symbols referenced by an absolute address (usually provided by the system's ROM). This is needed for ESP8266 targets as some C stdlib functions are provided by the MCU's own ROM code to reduce the final code footprint, and therefore those functions' implementation was removed from the compiler's support libraries. This means that unless `LINK_RUNTIME` is set (which lets tooling look at more libraries to resolve symbols) the build process will fail as tooling is unaware of the ROM symbols' existence. With this change, fixed-address symbols can be exposed to the symbol resolution step when performing natmod linking. If there are symbols coming in from a fixed-address symbols list and internal code or external libraries, the fixed-address symbol address will take precedence in all cases. Although this is - in theory - also working for the whole range of ESP32 MCUs, testing is currently limited to Xtensa processors and the example natmods' makefiles only make use of this commit's changes for the ESP8266 target. Natmod builds can set the MPY_EXTERN_SYM_FILE variable pointing to a linkerscript file containing a series of symbols (weak or strong) at a fixed address; these symbols will then be used by the MicroPython linker when packaging the natmod. If a different natmod build method is used (eg. custom CMake scripts), `tools/mpy_ld.py` can now accept a command line parameter called `--externs` (or its short variant `-e`) that contains the path of a linkerscript file with the fixed-address symbols to use when performing the linking process. The linkerscript file parser can handle a very limited subset of binutils's linkerscript syntax, namely just block comments, strong symbols, and weak symbols. Each symbol must be in its own line for the parser to succeed, empty lines or comment blocks are skipped. For an example of what this parser was meant to handle, you can look at `ports/esp8266/boards/eagle.rom.addr.v6.ld` and follow its format. The natmod developer documentation is also updated to reflect the new command line argument accepted by `mpy_ld.py` and the use cases for the changes introduced by this commit. Signed-off-by: Alessandro Gatti <a.gatti@frob.it> |
||
|---|---|---|
| .github | ||
| docs | ||
| drivers | ||
| examples | ||
| extmod | ||
| lib | ||
| logo | ||
| mpy-cross | ||
| ports | ||
| py | ||
| shared | ||
| tests | ||
| tools | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
| .gitignore | ||
| .gitmodules | ||
| .pre-commit-config.yaml | ||
| ACKNOWLEDGEMENTS | ||
| CODECONVENTIONS.md | ||
| CODEOFCONDUCT.md | ||
| CONTRIBUTING.md | ||
| LICENSE | ||
| pyproject.toml | ||
| README.md | ||
The MicroPython project
This is the MicroPython project, which aims to put an implementation of Python 3.x on microcontrollers and small embedded systems. You can find the official website at micropython.org.
WARNING: this project is in beta stage and is subject to changes of the code-base, including project-wide name changes and API changes.
MicroPython implements the entire Python 3.4 syntax (including exceptions,
with, yield from, etc., and additionally async/await keywords from
Python 3.5 and some select features from later versions). The following core
datatypes are provided: str(including basic Unicode support), bytes,
bytearray, tuple, list, dict, set, frozenset, array.array,
collections.namedtuple, classes and instances. Builtin modules include
os, sys, time, re, and struct, etc. Some ports have support for
_thread module (multithreading), socket and ssl for networking, and
asyncio. Note that only a subset of Python 3 functionality is implemented
for the data types and modules.
MicroPython can execute scripts in textual source form (.py files) or from precompiled bytecode (.mpy files), in both cases either from an on-device filesystem or "frozen" into the MicroPython executable.
MicroPython also provides a set of MicroPython-specific modules to access hardware-specific functionality and peripherals such as GPIO, Timers, ADC, DAC, PWM, SPI, I2C, CAN, Bluetooth, and USB.
Getting started
See the online documentation for the API reference and information about using MicroPython and information about how it is implemented.
We use GitHub Discussions as our forum, and Discord for chat. These are great places to ask questions and advice from the community or to discuss your MicroPython-based projects.
For bugs and feature requests, please raise an issue and follow the templates there.
For information about the MicroPython pyboard, the officially supported board from the original Kickstarter campaign, see the schematics and pinouts and documentation.
Contributing
MicroPython is an open-source project and welcomes contributions. To be productive, please be sure to follow the Contributors' Guidelines and the Code Conventions. Note that MicroPython is licenced under the MIT license, and all contributions should follow this license.
About this repository
This repository contains the following components:
- py/ -- the core Python implementation, including compiler, runtime, and core library.
- mpy-cross/ -- the MicroPython cross-compiler which is used to turn scripts into precompiled bytecode.
- ports/ -- platform-specific code for the various ports and architectures that MicroPython runs on.
- lib/ -- submodules for external dependencies.
- tests/ -- test framework and test scripts.
- docs/ -- user documentation in Sphinx reStructuredText format. This is used to generate the online documentation.
- extmod/ -- additional (non-core) modules implemented in C.
- tools/ -- various tools, including the pyboard.py module.
- examples/ -- a few example Python scripts.
"make" is used to build the components, or "gmake" on BSD-based systems.
You will also need bash, gcc, and Python 3.3+ available as the command python3
(if your system only has Python 2.7 then invoke make with the additional option
PYTHON=python2). Some ports (rp2 and esp32) additionally use CMake.
Supported platforms & architectures
MicroPython runs on a wide range of microcontrollers, as well as on Unix-like (including Linux, BSD, macOS, WSL) and Windows systems.
Microcontroller targets can be as small as 256kiB flash + 16kiB RAM, although devices with at least 512kiB flash + 128kiB RAM allow a much more full-featured experience.
The Unix and Windows ports allow both development and testing of MicroPython itself, as well as providing lightweight alternative to CPython on these platforms (in particular on embedded Linux systems).
The "minimal" port provides an example of a very basic MicroPython port and can be compiled as both a standalone Linux binary as well as for ARM Cortex M4. Start with this if you want to port MicroPython to another microcontroller. Additionally the "bare-arm" port is an example of the absolute minimum configuration, and is used to keep track of the code size of the core runtime and VM.
In addition, the following ports are provided in this repository:
- cc3200 -- Texas Instruments CC3200 (including PyCom WiPy).
- esp32 -- Espressif ESP32 SoC (including ESP32S2, ESP32S3, ESP32C3, ESP32C6).
- esp8266 -- Espressif ESP8266 SoC.
- mimxrt -- NXP m.iMX RT (including Teensy 4.x).
- nrf -- Nordic Semiconductor nRF51 and nRF52.
- pic16bit -- Microchip PIC 16-bit.
- powerpc -- IBM PowerPC (including Microwatt)
- qemu -- QEMU-based emulated target (for testing)
- renesas-ra -- Renesas RA family.
- rp2 -- Raspberry Pi RP2040 (including Pico and Pico W).
- samd -- Microchip (formerly Atmel) SAMD21 and SAMD51.
- stm32 -- STMicroelectronics STM32 family (including F0, F4, F7, G0, G4, H7, L0, L4, WB)
- webassembly -- Emscripten port targeting browsers and NodeJS.
- zephyr -- Zephyr RTOS.
The MicroPython cross-compiler, mpy-cross
Most ports require the MicroPython cross-compiler to be built first. This program, called mpy-cross, is used to pre-compile Python scripts to .mpy files which can then be included (frozen) into the firmware/executable for a port. To build mpy-cross use:
$ cd mpy-cross
$ make
External dependencies
The core MicroPython VM and runtime has no external dependencies, but a given port might depend on third-party drivers or vendor HALs. This repository includes several submodules linking to these external dependencies. Before compiling a given port, use
$ cd ports/name
$ make submodules
to ensure that all required submodules are initialised.