... 2Mbytes flash memory, voltage regulator, 2 channels DB-9 serial port connector, 1 USB connector, switches and LED which is used ... feature:Loading codes easily through bootstrap and serial port “0”(DB-9, J3) ,or USB port(J25)2 connectors(DB-9, RS ... A pair of MAX213E linear driver accepts expansion serial port “2”& “3” then add new serial debugging, not occupy internal serial port. Signal put out through ...