annotations:
STM32F407
BKIN - PA6, PB12, PE15
CH1N - PA7, PB13, PE8
CH2N - PB0, PB14, PE10
CH3N - PB1, PB15, PE12
ETR - PA12, PE7
CH1 - PA8, PE9
CH2 - PA9, PE11
CH3 - PA10, PE13
CH4 - PA11, PE14
F407 at full speed 168MHz