In the STM32F303 datasheet is written that "no external termination series resistor are required on USB_D+ and USB_D-, the matching impedance is already included in the embedded driver." However, if I look at the STM32F3DISCOVERY board I see 22 Ohm termination series resistors before the CN2 (USB-USER connector).Do I need them in my design or not? Is it necessary also to design the signal traces in the PCB in order to show a particular characteristic impedance?
