NEC μCOM series

The μCOM series has its roots in one of the world's earliest microprocessor chipsets, the two-chip processor μPD707 / μPD708.

Early in 1970, Coca Cola Japan set out to increase the efficiency of their sales outlets by introducing new POS terminals.

Sharp was contracted to build these terminals, and NEC in turn to develop a chipset.

The chipset development was complete in December 1971, at about the same time as other early microprocessors in the USA.

A number of peripheral integrated circuits were provided for the μPD751:[4] The μCOM-41 (μPD541) is a PMOS microprocessor in a 42-pin package.

It has built-in ROM and RAM as well as keyboard, display, and printer controllers.

To overcome this problem, NEC introduced the μCOM-80F (μPD8080AF) which is completely compatible with the Intel 8080 in all details.

[6]: 117  With the TK-80, NEC offered a development board for μCOM-80, which due to its low price became popular with hobbyists.

[6]: 167–172  The μPD780C-1 was used in Sinclair's ZX80, ZX81 and early versions of the ZX Spectrum, in several MSX and NEC (PC-6000, PC-8000, PC-8800) computers, in musical synthesizers such as Oberheim OB-8, and in Sega's SG-1000 game console.

[5]: 250  [6]: 211–209  CMOS microcontrollers up to μPD80C50 followed,[8]: 345–355  but an Intel 8051 compatible product, which is the 8-bit industry standard, was never offered.

The V register is a vector register that stores the upper 8 bits of the address of the working memory area, and the short address space which is fixed in the current 78K series can be freely arranged.

[9]: 321–323  [10]: 4-35–4-44  In the μPD7807 and later, the ALU is expanded to 16 bit and an EA register is added for 16-bit operation.

The μCOM-16 is a NEC original 16-bit microprocessor, implemented in two chips, the μPD755 (register + ALU) and μPD756 (controller), in 1974.