The STM8 is an 8-bit microcontroller family by STMicroelectronics an extended variant of the ST7 microcontroller architecture. STM8 microcontrollers are particularly low cost for a full-featured 8-bit microcontroller.
[env:stable]
platform = ststm8
board = ...
...
[env:development]
platform = https://github.com/platformio/platform-ststm8.git
board = ...
...
Please navigate to documentation.