Hi list,

I've done a PoC port of Zephyr to STM32F103VE MCU on a EB-STM_06 dev
board. The port is rather minimal, most of the configuration is
hardcoded. The MCU is configured to use internal HSI clock source, with
PLL feeding a 36MHz clock to SYSCLK and AHB/APB (tried to make it board
agnostic). The minimal UART driver assumes that USART1 will be used with
a fixed speed of 9600kbps. The the best of my knowledge, this should be
enough as a starting point for porting to other boards.

The source code lives here:
https://github.com/bboozzoo/zephyr/tree/bboozzoo/stm32f103 in
bboozzoo/stm32f103 branch.

Obligatory video: https://goo.gl/photos/AGhfXYvv8CswjRRu7 (sorry for the
background sound and overall potato quality). In the vide I flash the
firmware through STLink, the board resets and starts the hello world
sample. The output is received via a USB RS232 adapter. The sample
program has been also modified to print an increasing loop counter, just
to make sure we're not looping the same content.

If anyone feels like this is worth working on I might be able to try and
clean it up a little bit and push out to Gerrit (once I get my access
issues resolved). I also have a couple of boards with STM32F3xx and
STM32L4xx MCUs so I might give these a try, unfortunately all of these
are Cortex-M4 based.

Has anyone looked at ports to Cortex-M0?

Cheers,