NT6880

NT6880 Keyboard Controller Features T T T T T T T Built-in 6502 8-bit CPU 2 MHz CPU operation frequency 5K bytes of ROM 160 bytes of SRAM One 8-bit programmable base timer with 1 - 256 µsec interval 29 programmable bi-directional I/O pins 3 LED direct sink pins T T T T T T T Mask optional for built-in RC oscillator with an external resistor or external ceramic resonator applied Mask optional for DATA/CLK driving capability Watch-dog timer reset Built-in power-on reset Built-in low voltage reset CMOS technology for low power consumption Available in 40 pin DIP package and 40 pad Chip Form General Description The NT6880 is a single chip micro-controller for keyboard applications. It incorporates a 6502 8-bit CPU core, 5K bytes of ROM and 160 bytes of RAM used as working RAM and stack area. It also includes 29 programmable bi-directional I/O pins and one 8-bit preloadable base timer. Additionally, it includes a built-in low voltage reset, a 4MHz RC oscillator requiring an externally applied resistor or a 4MHz ceramic resonator and a watch-dog timer that prevents system standstill. Pin Configuration Pad Configuration P 1 7 P 1 6 P 1 5 P 1 4 P 1 3 P 1 2 P 1 1 P 1 0 P 0 7 P 0 6 GND NC DATA CLK P30 P31 P32 P33 P34 RESET P00 P01 P02 P03 P04 P05 P06 P07 P10 P11 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 OSCI R/OSCO V DD LED2 LED1 LED0 P27 P26 P25 P24 P23 P22 P21 P20 P17 P16 P15 P14 P13 P12 LED1 36 P20 P21 P...