General Description
The NT68P81 is a single chip micro-controller for USB keyboard applications. It incorporates a 6502C 8 -bit CPU core, 6K bytes of OTP ROM, and 256 bytesof 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.

FEATUREs
  Built-in 6502C 8 -bit CPU
  3 MHz CPU operation frequency when oscillator is running at 6 MHz
  6K bytes of OTP (one time programming) ROM
  256 bytes of SRAM
  One 8 -bit programmable base timer with pre-divider circuit
  29 programmable bi-directional I/O pins including two external interrupts
  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 supported endpoints
  Remote wakeup provided
  CMOS technology for low power consumption
  40-pin DIP package, 42-pad Dice form and COB