... micro-controllor, 1MBytes SRAM, 2Mbytes flash memory, voltage regulator, 2 channels DB-9 serial port connector, 1 USB connector, switches ... DB-9, RS-232) , 1 USB connector4 serial interface (2 internal + 2 URAT)Voltage regulatorInterface used in smart card slotSAM slotSupport LCD ... and J2. A pair of MAX213E linear driver accepts expansion serial port “2”& “3” then add new serial debugging, not occupy ...