MicroPython libraries

Warning

Important summary of this section

• MicroPython implements a subset of Python functionality for each module.
• To ease extensibility, MicroPython versions of standard Python modules usually have u (micro) prefix.
• Any particular MicroPython variant or port may miss any feature/function described in this general documentation, due to resource constraints.

This chapter describes modules (function and class libraries) which are built into MicroPython. There are a few categories of modules:

• Modules which implement a subset of standard Python functionality and are not intended to be extended by the user.
• Modules which implement a subset of Python functionality, with a provision for extension by the user (via Python code).
• Modules which implement MicroPython extensions to the Python standard libraries.
• Modules specific to a particular port and thus not portable.

Note about the availability of modules and their contents: This documentation in general aspires to describe all modules and functions/classes which are implemented in MicroPython. However, MicroPython is highly configurable, and each port to a particular board/embedded system makes available only a subset of MicroPython libraries. For officially supported ports, there is an effort to either filter out non-applicable items, or mark individual descriptions with “Availability:” clauses describing which ports provide a given feature. With that in mind, please still be warned that some functions/classes in a module (or even the entire module) described in this documentation may be unavailable in a particular build of MicroPython on a particular board. The best place to find general information of the availability/non-availability of a particular feature is the “General Information” section which contains information pertaining to a specific port.

Beyond the built-in libraries described in this documentation, many more modules from the Python standard library, as well as further MicroPython extensions to it, can be found in the micropython-lib repository.

Python standard libraries and micro-libraries

The following standard Python libraries have been “micro-ified” to fit in with the philosophy of MicroPython. They provide the core functionality of that module and are intended to be a drop-in replacement for the standard Python library.

These modules which begin with the letter “u” are also accessible without the “u” prefix:

ubinascii uhashlib uheapq ujson urandom uos ure ustruct utime uzlib uerrno

The reason for this is to ease porting in cases where the MicroPython module is a compatible subset of the standard library. For instance the utime module represents time the same way but contains only a subset of the functions in the standard time module, so it may be imported either way. Ported software may still have subtle issues, however, due to the lack of support for daylight savings time or more obvious problems due to an unsupported function. If convenient, you can always create an alias for a module. For instance, to make io` an alias for ``uio you would import the uio module like this: import uio as io.

Another goal was to allow these modules to be replaced with user-code that might supply some of the missing features, but we do not support user written modules at this time.

• _thread — Low-level threading API
• array – arrays of numeric data
• builtins – builtin functions, constants, exceptions, and decorators
• cmath – mathematical functions for complex numbers
• gc – control the garbage collector
• math – mathematical functions
• sys – system specific functions
• ubinascii – binary/ASCII conversions
• ucollections – collection and container types
• uerrno – system error codes
• uhashlib – hashing algorithm
• uheapq – heap queue algorithm
• uio – input/output streams
• ujson – JSON encoding and decoding
• uos – basic “operating system” services
• urandom – Random Number Generation
• ure – regular expressions
• ustruct – pack and unpack primitive data types
• utime – time related functions

MicroPython-specific libraries

Functionality specific to the MicroPython implementation is available in the following libraries.

• machine — functions related to the board
• micropython – access and control MicroPython internals
• uctypes – access binary data in a structured way

Libraries specific to Satlink 3 and XLink 500

The following libraries are specific to Satlink 3 and XLink 500 :

• serial — Serial port class
• sl3 — Satlink 3 and XLink 500 API