NT6881

NT6881 USB Keyboard Micro-Controller Features n Built-in 6502 8-bit CPU n 3 MHz CPU operation frequency when oscillator is running at 6 MHz n 6K bytes of ROM n 256 bytes of SRAM n One 8-bit programmable base timer with pre-divider circuit n 29 programmable bi-directional I/O pins including two external interrupts n n n n n n n n n 3 LED direct sink pins with internal serial resistors On-chip oscillator (Crystal or Ceramic Resonator) Watch-dog timer reset Built-in power on reset USB interface 3 Endpoints provided Remote Wakeup provided CMOS technology for low power consumption 40-pin DIP package, 42-pad Chip Form and COB General Description The NT6881 is a single chip micro-controller for USB keyboard applications. It incorporates a 6502 8-bit CPU core, 6K bytes of mask ROM, and 256 bytes of RAM used as working RAM and stack area. It also includes 29 programmable bi-directional I/O pins with built-in resistors, and one 8-bit pre-loadable base timer. Additionally, it includes a built-in power-on reset, a builtin low voltage reset, an oscillator that requires crystal or ceramic resonator applied, and a watch-dog timer that prevents system standstill. Pin Configuration Pad Configuration V D P V C P G N D G N D O S C I 42 O S C O 41 V C C V C C 38 40 39 37 VDM 5 36 35 P30 P31 P32 P33 P34 RESET P00 P01 P02 P03 6 34 7 33 P25 P24 P23 P22 P21 P20 P17 8 9 10 30 11 29 12 28 13 27 14 16 15 17 18 19 20 21 22 23 24 25 26 P26 LED2 LED1 LED0 P27 GND VCP VDP VDM P30 P31 INT0/P32 INT1/P33 ...