Found this site but hasn’t been updated since 2015 
github clementleger/Smoothieware-STM32
Imported from wikidot
Yes, that port was only partial, and was barely tested.
If you are looking to run Smoothie on more powerful hardware, instead of looking at STM, you should follow the current project direction where we are porting the firmware to the powerful LPC4330, a Cortex-M4F+M0.
What were you looking at this for ?
I’m looking for STM32 support because I already have a commercial 3d printer based on an STM32 board and would like to run Smoothieware on that printer. I know the schematics so I could modify the existing STM32 support to fit my board, but porting from LPC4330 is a bit too much of effort, taking in account that Smoothie doesn’t have any porting guide or any documentation on its internal architecture at all.