stm32 stuff but serial port not working currently
sort stm32 serial port interrupt
formatting only
formatting only
formatting only
upgrade calcs to offcial algorithm
formatting only
formatting only
now brr value is calced direct by detil::get_baud_rate_values
formatting only
formatting only
initial commit moved from stm32f4 version
removed some redundundant specialisations of get_irq_number
some testing- need more
initial commit
formatting only
initial commit
formatting - add check of valid mcu definition too
formatting and update  include guard
formatting and comments only