NT6868A is a single chip micro-controller for keyboard applications. It incorporates a 6502 8-bit CPU core, 4K bytes of ROM, and 128 bytes of RAM used as working RAM and stack area. It also includes 29 programmable bi-directional I/O pins and one 8-bit pre-loadable base timer. Additionally, it includes a built-in low voltage reset, a 4MHz RC oscillator that requires only a resistor externally applied or a 4MHz ceramic resonator, and a watch-dog timer that prevents system standstill.
The Novatek NT6868A is a single-chip micro-controller designed specifically for keyboard applications. It incorporates a 6502 8-bit CPU core, 4K bytes of ROM, and 128 bytes of SRAM used as working RAM and stack area. The device includes 29 programmable bi-directional I/O pins and one 8-bit programmable base timer.
| CPU Core | 6502 8-bit CPU |
|---|---|
| ROM Capacity | 4K bytes |
| SRAM Capacity | 128 bytes |
| CPU Operation Frequency | 2 MHz |
| I/O Pins | 29 programmable bi-directional |
| LED Pins | 3 direct sink pins |
| Timer Interval | 1 - 256 usec |
| Operating Voltage | +4.5V to 5.5V |
| Operating Temperature | 0°C to +70°C |
The base timer is an 8-bit counter with a 1MHz clock source that can be enabled/disabled by the CPU and generates a timer interrupt when it overflows.
The Watch-Dog Timer protects programs against system standstill by causing a system reset if it is not cleared within every 0.175 second during normal operation.
When the voltage level of the power supply is below a threshold of 3.0V, the Low Voltage Reset (LVR) circuit issues a reset output to the chip.