[distortos-development] Support for STM32F1 chips

[Kamil S. <dis...@di...>]

Hello!

New family of chips is supported by distortos since today! It is now
possible to use any of 94 STM32F1 chips – they are all available in
Kconfig configuration system and supported by source code. This
addition increases total number of chips supported by distortos to 209.

Merged changes include support and test configuration for NUCLEO-F103RB 
board with STM32F103RB chip (72MHz max).

Configuration of chip’s clocks and PLLs can be done entirely in Kconfig
configuration tool – just as for STM32F4.

All selected options are verified either by Kconfig configuration tool
or by compile-time checks in source code (static_assert(...) or
preprocessor). The checks range from simple value verifications
(whether the value is in allowed range), through dependency checks
(e.g. you cannot select HSE clock as source of PLL without enabling
it), through chip variations (e.g. allowed range for PLL multiplier is
different for STM32F103 than for STM32F105 and STM32F107, additional
PLLs are only present in STM32F105 or STM32F107) to validation of final
setting (e.g. whether all clock-related options result in valid
frequencies for the selected chip). All of that makes creating a wrong
configuration (almost (; ) impossible, greatly simplifying new hardware
bring-up and reducing time required to implement low-level chip
initialization.

News article on project's website:
http://distortos.org/news/support-stm32f1-chips/

Regards,
Kamil Szczygieł