68 lines
2.5 KiB
Markdown
68 lines
2.5 KiB
Markdown
Example of embedding MicroPython in a standlone C application
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=============================================================
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This directory contains a (very simple!) example of how to embed a MicroPython
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in an existing C application.
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A C application is represented by the file hello-embed.c. It executes a simple
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Python statement which prints to the standard output.
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Building the example
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--------------------
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Building the example is as simple as running:
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make
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It's worth to trace what's happening behind the scenes though:
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1. As a first step, a MicroPython library is built. This is handled by a
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separate makefile, Makefile.upylib. It is more or less complex, but the
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good news is that you won't need to change anything in it, just use it
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as is, the main Makefile shows how. What may require editing though is
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a MicroPython configuration file. MicroPython is highly configurable, so
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you would need to build a library suiting your application well, while
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not bloating its size. Check the options in the file "mpconfigport.h".
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Included is a copy of the "minimal" Unix port, which should be a good start
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for minimal embedding. For the list of all available options, see
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py/mpconfig.h.
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2. Once the MicroPython library is built, your application is compiled
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and linked it. The main Makefile is very simple and shows that the changes
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you would need to do to your application's Makefile (or other build
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configuration) are also simple:
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a) You would need to use C99 standard (you're using this 15+ years old
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standard already, not a 25+ years old one, right?).
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b) You need to provide a path to MicroPython's top-level dir, for includes.
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c) You need to include -DNO_QSTR compile-time flag.
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d) Otherwise, just link with the MicroPython library produced in step 1.
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Out of tree build
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-----------------
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This example is set up to work out of the box, being part of the MicroPython
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tree. Your application of course will be outside of its tree, but the
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only thing you need to do is to pass MPTOP variable pointing to
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MicroPython directory to both Makefiles (in this example, the main Makefile
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automatically passes it to Makefile.upylib; in your own Makefile, don't forget
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to use a suitable value).
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A practical way to embed MicroPython in your application is to include it
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as a git submodule. Suppose you included it as libs/micropython. Then in
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your main Makefile you would have something like:
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~~~
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MPTOP = libs/micropython
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my_app: $(MY_OBJS) -lmicropython
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-lmicropython:
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$(MAKE) -f $(MPTOP)/examples/embedding/Makefile.upylib MPTOP=$(MPTOP)
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~~~
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