Terminology

BareMetal

Systems without (fully mature) OS, for example based on MCU system. When running on bare metal systems, MicroPython effectively becomes a user-oriented operating system through a command interpreter (REPL).

Board

PCB board. Generally, this term is used to indicate MCU system specific model. At times, actual application is MicroPython port reference to a specific board (may also mean Unix port boardless ports)。

Callee-owned Tuple

Tuples returned by some built-in functions/methods contain data that is valid for a limited time, usually until the next call to the same function (or set of related functions). After the next call, you can change the data in the tuple. This results in the following restrictions on the use of tuples owned by the callee-unable to store references to them. The only valid operation is to extract values from it (including making a copy). The tuples owned by Callee are MicroPython-specific constructs (not available in the general Python language) for memory allocation optimization. The idea is that the tuple owned by the callee is allocated once and stored in the callee. Subsequent calls do not require allocation, allowing multiple values to be returned when they cannot be allocated (for example, in an interrupt context) or undesirable (because allocation inherently causes memory fragmentation). Please note that the tuple owned by the callee is actually a variable tuple, which makes the exception to Python’s rule that tuples are immutable. (It may be interesting why tuples are used for such purposes instead of mutable lists-the reason is that the list can also be changed from the user application side, so the user can perform operations on the list owned by the callee is not expected and possible Causes problems; tuples are protected.) Instead of a variable list-the reason is that the list can also be changed from the user application side, so the user can perform operations on the list owned by the callee, which the callee does not expect and may cause problems; a tuple is protected. (Instead of a mutable list-the reason is that the list can also be changed from the user application side, so the user can perform operations on the list owned by the callee, which the callee does not expect and may cause problems; a tuple is protected.)

CPython

CPython is the reference implementation of the Python programming language and the most famous programming language that most people used. However, it is one of many implementations (including Jython, IronPython, PyPy, etc., including MicroPython). ince there is no formal Python language specification, only CPython documentation, it is not always easy to draw a line between the Python language and a specific implementation of CPython. However, this leaves more freedom for other implementations. For example, MicroPython does many things different from CPython, while still eager to become a Python language implementation.

GPIO

Universal input/output. The easiest way to control electrical signals. Through GPIO, users can configure hardware signals as input or output， Aslo to set or get its digital signal value (logic “0” or “1”). Use of MicroPython machine.Pin and machine.Signal class extraction access to GPIO permissions。

GPIO port

A set of GPIO pins, usually based on the hardware characteristics of the pins (for example: can be controlled by the same register).

Interned String

The string referenced by its (unique) identifier, not its address. Therefore, you can quickly compare internship strings by identifier, rather than by content. The disadvantage of the internship string is that the internship operation takes time (proportional to the number of existing internship strings, that is, it becomes slower and slower with time), and the space for the internship string is not recyclable. String training is done automatically by the MicroPython compiler and runtime, when the implementation needs it (for example, the function keyword parameter is represented by the training string id) or considered to be beneficial (for example, for short enough strings, there is a chance to repeat, So internship) They will save memory on the copy). Due to the above shortcoming, most strings and I/O operations do not produce actual strings。

MCU

Microcontroller. Compared with a complete computing system, microcontrollers usually have much fewer resources, but they are also smaller, less expensive, and consume less power. MicroPython is designed to be small and optimized to run on a generally recent microcontroller.

micropython-lib

MicroPython (usually) is distributed as a single executable/binary file with few built-in modules. Unlike the CPython , MicroPython has no extended standard libraryMicroPython. But there is a related but independent project. micropython-lib ，The project provides many implementations from modules in the standard library. However, a larger subset of these modules requires a POSIX-like environment (Partially supports Linux, MacOS, Windows), so it can only be run on the MicroPython Unix port. Some subsets of modules are also available on baremetal ports.

Unlike the CPython single-chip standard library, the micropython-lib module is designed to be copied manually or Use :term:`upip`to install separately.

MicroPython port

MicroPython supports different boards （ boards）, RTOS and OS can adapt to the new system relatively easily. MicroPython that supports a specific system is called the “port” of that system. The functional characteristics of different ports vary greatly. This document is intended for Common APIs available on different ports （”MicroPython core”）provide references. Note: Some ports may delete the API described here (Due to resource constraints). Such differences, as well as port-specific extensions beyond the core functionality of MicroPython, will be in separate, This is described in the port-specific files.

MicroPython Unix port

Unix port is MicroPython（ MicroPython ports）one of the main port. It is designed to run on POSIX compatible operating systems such as Linux, MacOS, FreeBSD, Solaris, etc. It is designed to run on POSIX compatible operating systems such as Linux, MacOS, FreeBSD, Solaris, etc， t is impossible for any two users to use the same board. Almost all modern operating systems have a certain degree of POSIX compatibility. At this time, the Unix port can be used as a “common basis” . Therefore, Unix ports are used for initial prototypes, different types, testing and development independent of machine characteristics, etc. We recommend all MicroPython users (even included only in MCU system Users running MicroPython) are familiar with the Unix (or Windows) port, because this port can improve work efficiency and is part of the MicroPython workflow.

PORT

MicroPython port or GPIO port . If you have not understood the above, it is recommended that you use the full specifications as in the example above.

STREAM

Also known as “file-like object””. An object that provides sequential read and write access to the underlying data. A stream object implements the corresponding interface, which consists of similar methods read() ， write() ，readinto() ，seek() ，flush() ，close() , etc. Streaming is an important concept in MicroPython, Many I/O objects implement the stream interface, so the context can be used consistently and interchangeably in different. More information about streams in MicroPython, see uio module。

upip

(Literally meaning “micro pip”). MicroPython’s package manager, inspired by CPython pip, but with smaller features and fewer features. upip can run on Unix port and baremetal ports (providing file system and network support).