Use USART 0 connected to the SIM card side to sniff the communication.
The card side can also measure ETU times.
Do proper pin initialization.
This code can already capture the ATR communication between phone and card.
because the applications share the board capabilities defined in
libboard/*/include/board.h and USB configurations are enabled according
to the previously defined capabilities in libcommon/source.usb.c, all
applications actually offer the same functions.
thus creating the trace application is only mainly a cosmetic change, as the
sniffer function will also be present and enabled in the cardem application.
