circuitpython/ports/bare-arm/README.md
Damien George 4fc2866f45 bare-arm: Clean up the code, make it run on an F405, and add a README.
This commit simplifies and cleans up the bare-arm port, and adds just
enough system and library code to make it execute on an STM32F405 MCU.

The mpconfigport.h configuration is simplified to just specify those
configuration values that are different from the defaults.  And the
addition of -fdata-sections and -ffunction-sections means the final
firmware is smaller than it previously was, by about 4200 bytes.

A README is also added.

Signed-off-by: Damien George <damien@micropython.org>
2021-03-19 14:20:26 +11:00

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Markdown

The bare-arm port
=================
This port is intended to be the bare-minimum amount of code and configuration
required to get MicroPython compiling and running on a bare-metal ARM-based
target. No external dependencies or libraries are needed for this build and
it shows exactly what hardware and system functionality MicroPython needs to
run.
To build, simply run `make` in this directory. The output will be
`build/firmware.elf` (and also corresponding `.bin` and `.dfu` files). This
firmware can run on an STM32F405-based board (eg a PYBv1.x) and `make deploy`
will program it to such an MCU when put in USB DFU mode. The output is a UART
at 115200 baud, with TX on PA0.
There are some simple demonstration code strings (see `main.c`) which are
compiled and executed when the firmware starts. They produce output on the
system's stdout.
The size of the firmware (the machine code that is programmed to the
microcontroller's flash/ROM) is currently around 61200 bytes.