NSC800

National Semiconductor

National Semiconductor Corporation's NSC800 was an interesting device, an 8-bit CMOS CPU with the instruction set of Zilog's Z80 and the multiplexed bus of Intel's 8085; like other chips of its day it was designed within the limitations of the 40-pin package and the available PCB layout techniques; its complement of peripheral chips included a unique HP-IL interface; in any case, the NCS800 appears to have been quite successful; it was still being sold as late as 1997.

Fabricated using P²CMOS technology; 3V to 12V power supply; fully compatible with Z80 instruction set; 158 instructions; 10 addressing modes; 22 internal registers; multiplexed bus structure; on-chip bus controller and clock generator; on-chip 8-bit dynamic RAM refresh circuitry; capable of addressing 64K Bytes of Memory and 256 I/O devices

2.5 MHz
4.0 MHz