Home > Zilog Z80

1 History

The Z80 came about when Federico Faggin left Intel after working on the 8080, and by July 1976 Zilog had the Z80 on the market. It was designed to be binary compatible with the Intel 8080 so that most 8080 code could run unmodified on it, notably the CP/M operating system.

The Z80 offered five real improvements over the 8080:

• an enhanced instruction set including new IX and IY index registers and instructions for them
• two instances of each register which could be quickly switched between, to speed up response to interruptIn computer engineering, an interrupt is a signal from a device which typically results in a context switch: that is, the processor sets aside what it's doing and does something else. Digital computers usually provide a way to start software routines in rs
• a limited ability for SIMDSIMD is an acronym for S ingle I nstruction, M ultiple D ata. It is a computing term that refers to a set of operations for efficiently handling large quantities of data in parallel, as in a vector processor or array processor. First popularized in large- (Single Instruction, Multiple Data) with block move and copy instructions. ¹
• a built-in DRAM refresh address counter that would otherwise have to be provided by external circuitry
• a much lower price

The Z80 quickly took over from the 8080 in the market, and became the most popular 8-bit CPU of all time - indeed, if one takes the absolute size of the market into account, the most successful CPU ever. Later versions increased in speed from the early models' 1 MHzA megahertz (MHz is one million (106) hertz, a measure of frequency. Megahertz in radio When used in the context of radio, MHz refers to the number of oscillations of electromagnetic radiation. Severel parts of the radio spectrum fall into the MHz range: up to as much as 20 MHz.

Perhaps key to the success of the Z80 was the built-in DRAM controller, which allowed systems to be built with fewer support chips. Competitor MOS Technology, IncMOS Technology, Inc. also known as Commodore Semiconductor Group was a microprocessor and calculator company famous for its 6502 processor. Commodore 64 showing some important MOS Technology circuits: the 6510 CPU and the 6581 (SID). Company history MOS o, maker of the famous 6502The MOS Technology 6502 is an 8-bit microprocessor designed by MOS Technology in 1975. When it was introduced it was the least expensive full featured CPU on the market by far, at about 1/6th the price, or less, of competing designs from larger companies processor, later included this very useful feature in its second generation color video chip VIC-IIThe VIC-II (Video Interface Chip II specifically known as the MOS Technology 6567/8562/8564 ( NTSC versions), 6569/8565/8566 ( PAL), is the integrated circuit chip tasked with generating composite video graphics and DRAM refresh signals in the Commodore 6.