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circuitpython/ports/minimal
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Damien George 999733b1fb minimal: Use soft float for CROSS=1 Cortex-M4 target. 
When compiled with hard float the system should enable FP access when it
starts or else FP instructions lead to a fault.  But this minimal port does
not enable (or use) FP and so, to keep it minimal, switch to use soft
floating point.  (This became an issue due to the recent commit
34c04d2319 which saves/restores FP registers
in the NLR state.)
 		2019-07-01 22:48:05 +10:00
..
Makefile minimal: Use soft float for CROSS=1 Cortex-M4 target. 2019-07-01 22:48:05 +10:00
README.md minimal/README: Update text to better describe what "make run" does. 2018-01-31 21:05:21 +11:00
frozentest.mpy minimal/frozentest: Recompile now that mpy format and version changed. 2019-03-08 15:53:05 +11:00
frozentest.py ports: Make new ports/ sub-directory and move all ports there. 2017-09-06 13:40:51 +10:00
main.c minimal/main: Allow to compile without GC enabled. 2018-05-21 13:13:21 +10:00
mpconfigport.h py/objdict: Make .fromkeys() method configurable. 2018-12-13 01:20:55 +11:00
mphalport.h ports: Make new ports/ sub-directory and move all ports there. 2017-09-06 13:40:51 +10:00
qstrdefsport.h ports: Make new ports/ sub-directory and move all ports there. 2017-09-06 13:40:51 +10:00
stm32f405.ld ports: Make new ports/ sub-directory and move all ports there. 2017-09-06 13:40:51 +10:00
uart_core.c ports: Make new ports/ sub-directory and move all ports there. 2017-09-06 13:40:51 +10:00

README.md

The minimal port

This port is intended to be a minimal MicroPython port that actually runs. It can run under Linux (or similar) and on any STM32F4xx MCU (eg the pyboard).

Building and running Linux version

By default the port will be built for the host machine:

$ make

To run the executable and get a basic working REPL do:

$ make run

Building for an STM32 MCU

The Makefile has the ability to build for a Cortex-M CPU, and by default includes some start-up code for an STM32F4xx MCU and also enables a UART for communication. To build:

$ make CROSS=1

If you previously built the Linux version, you will need to first run make clean to get rid of incompatible object files.

Building will produce the build/firmware.dfu file which can be programmed to an MCU using:

$ make CROSS=1 deploy

This version of the build will work out-of-the-box on a pyboard (and anything similar), and will give you a MicroPython REPL on UART1 at 9600 baud. Pin PA13 will also be driven high, and this turns on the red LED on the pyboard.

Building without the built-in MicroPython compiler

This minimal port can be built with the built-in MicroPython compiler disabled. This will reduce the firmware by about 20k on a Thumb2 machine, and by about 40k on 32-bit x86. Without the compiler the REPL will be disabled, but pre-compiled scripts can still be executed.

To test out this feature, change the MICROPY_ENABLE_COMPILER config option to "0" in the mpconfigport.h file in this directory. Then recompile and run the firmware and it will execute the frozentest.py file.