NC24NC8VCCIO4RXD5RI6GND7DSR9DCD10CTS11CBUS412CBUS213CBUS314USBDP15USBDM163V3OUT17GND18RESET19VCC20GND21CBUS122CBUS023AGND25TEST26OSCI27OSCO28TXD1DTR2RTS3