# PlatformIO example with latest libopencm3 version

Literally just the cdcacm.c example used with the newest libopencm3 framework version and compiler version.

For repackaging libopencm3, a Linux machine was used, https://github.com/libopencm3/libopencm3 was cloned, make was executed, the .a files in lib/ were deleted (PlatformIO compiles everything from source), then a package.json was added based on the previous one, but with updated version info (see package.json). The thing was then uploaded to a repo (https://github.com/maxgerhardt/pio-libopencm3-repackage) and pointed to by

platform_packages = 
   framework-libopencm3@https://github.com/maxgerhardt/pio-libopencm3-repackage.git

That's literally it.

For upgrading the compiler version, the available versions for toolchain-gccarmnoneeabi were inspected and using semantic versioning, the version expression ~1.90301.0 is used to select a GCC 9.3.1 compiler version, again using an extended platform_packages command.

One can also use a local toolchain folder, given that it has a package.json in it akin to the one in PlatformIO packages (see <user home>/.platformio/packages/toolchain-gccarmnoneeabi/package.json) and can then be pointed to using `

platform_packages = 
   toolchain-gccarmnoneeabi@file://<path to toolchain folder here>

What does this example do?

It creates a USB CDC (virtual serial port).

Flash the firmware onto a Bluepill, e.g. using an ST-Link, and plug connect a micro-USB cable to the Bluepill.

You will see..

A new COM port upon plugging in the device.