How did the Z80 instruction set differ from the 8080?
Oct 26, 2016 · The Zilog Z80 microprocessor, known for its use in the ZX Spectrum, was designed to be a backwards-compatible extension to the Intel 8080 processor. It introduced …
Comparing raw performance of the Z80 and the 6502
May 21, 2022 · The Z80's fastest memory fetch — the first half of an operation fetch — takes two cycles. That's always paired with another two cycles for refresh though, so the shortest …
z80 - What is R register and DRAM refresh internal operation ...
Apr 14, 2024 · The Z80 CPU has a built-in feature to support refreshing DRAM memory, by keeping a 7-bit refresh counter in the register R. The refresh counter is increased by 1 after …
z80 - Decoding Logic and Memory Systems for 8-bit computer
Apr 27, 2020 · 8 I have solved a similar problem when reworking my 8085-based OMEN Alpha computer for the Z80 CPU. The memory part is really simple: You have two memories, 32k …
Uses for the halt instruction? - Retrocomputing Stack Exchange
Jun 16, 2018 · Unlike 8080 and Z80 the 8085 also tristates all data, address and bus control signals. *3 - While the 6502 did not feature a halt instruction (not until the 65C02), Atari's TIA …
What was the last commercial Z80-based computer sold?
Jul 13, 2025 · AFAICT, the last Z80 desktop computer sold was the TRS-80 Model 4, in production until late 1991. If you include notebook computers, the Amstrad NC200 was …
Did any computers use the Z80B? - Retrocomputing Stack Exchange
Jan 10, 2018 · The Z80 was one of the most popular CPUs of the seventies and eighties. In almost all cases that I know of, the version used was the Z80A, rated for 4 MHz, sometimes …
z80 - How do I Interface a PS/2 Keyboard without Modern …
Mar 21, 2019 · It's a part of standard Z80 family chips and has two channels. I used it for PS/2 keyboard and USB connection to my breadboard Z80 computer running at 2.4576 MHz. …
Z80: asymmetric use of B in DJNZ (B is a low byte) vs. BC in LDIR ...
Aug 18, 2022 · Z80 registers are specialized. Much like A, X and Y have different features on a 6502. Inherited Basics Most of this is inherited straight from the 8080: A - General purpose …
Z80 - "LD (nn), dd" command cycle - Retrocomputing Stack …
Apr 28, 2021 · Indeed, the Z80 manual is one of the most detailed with respect to the bus cycle descriptions and has definitely more interesting pages than the one you showed. You want to …