The Z80 microprocessor is an 8-bit [[CPU]] with a 4-bit ALU and a 16-bit address bus capable of direct access to 64KB of memory space. The Z80 is a little-endian CPU, meaning it stores 16-bit values with the least significant byte first, followed by the most significant byte. It has a language of 252 root instructions and with the reserved 4 bytes as prefixes, access to an additional 308 instructions. The Z80 was modelled after the [[8080|Intel 8080]] and contains the seventy-eight 8080 opcodes as a subset to its language.
The Zilog Z80 is an upgraded version of the Intel 8080 and is fully compatible with itat the software level. The Z80 adds more registers, better instructions, faster performance, and improved interrupt handling, making it more powerful and efficient than the 8080.
While not in the same league as the Intel 80x86 or the [[Motorola 68000]] series, the Z80 is extremely useful for low cost control applications. One of the more useful features of the Z80 is the built-in refresh circuitry for ease of design with DRAMs.