add stm32f103c8 based board

[acr]

i try add this cheap board http://wiki.stm32duino.com/index.php?title=Blue_Pill
it based on STM32F103C8T6, 64Kb flash
so i start from RT-STM32F103-MAPLEMINI that is based on STM32F103CBT6, 128Kb flash
i replace cpu to #define STM32F103x6 in board.h
and here strange stuffs begin, chibios say that i don't have usb
i found in stm32_registry.h that STM32F103x6 is Low Density device
but http://www.st.com/content/st_com/en/pro ... 103c8.html
here st say that this is medium device it has same features as STM32F103CBT6 but 64Kb flash and do not have PORTE
not sure this is bug or feature

[Giovanni]

Hi,

You should verify on the datasheet if the registry matches exactly the device.

Giovanni

[acr]

i think it registry compatible devices, binary from STM32F103CBT6 run on STM32F103C8T6 without problem, but it hacky way