Sharp MZ

The /WAIT facility is for any device which needs to supply it and it is a common Z80 signal: for instance, when you plug you own PCB in the expansion bus (/EXWAIT signal) and want to make the CPU able to adjust to slow chips (/EXWAIT signal is connected to Z80 /WAIT signal). MZ-80 K has no LSI to ha...

I would be interested in MZ-80A upgrade board with a 40/80 columns card. Few years ago, I acquired an ill-working MZ-80A with 40/80 modding but I may restore it in its original hardware as it is not stable.

MZ-2500 in the FPGA emulator will be the summum as I think it is the last of the B series.

Also, the snow effects on MZ-80 K is merely due the fact that Z80 is reading/writing in VRAM while video circuit is reading bytes from VRAM precisely because there is no setting /WAIT to 0 when drawing during horizontal rasterline.

yes, it looks MZ-80 A has a similar scheme but I didn't see it clearly in the service manual. If true, MZ-80 A may benefit of the same tricks to make fast display.

When Z80 tries to access memory or I/O port, there is a moment when you drive a chip to read/write a byte, you need the Z80 to be paused because that chip may need more time to handle the operation. For that purpose, a chip may set the Z80 /WAIT input pin to make the Z80 inserting more cycles (idlin...

Ah quand même !

You need my PAL version of EmuZ-700 (https://github.com/SHARPENTIERS/EmuZ-700-1500/releases) or the last version of mz800emu. The video timing was problematic on every emulator because they were not respectful about the wait states cycles accuracy that demo demands.

Ah là là, je n'ai vraiment pas de place pours ces mastodontes .

You mean the stickers were not over the plastic but under? I had once tried to find but the only one I could find was Japanese.

They are phoneme alphabets : katakana in the first set and hiragana in the second set from columns 8 to B and their ponctuations. I believe there are some kanji symbols in column B. For instance "2020年03月22日". 年 (nen), 月 (gatsu) and 日 (nichi) respectively meaning “year”, “month” et “day”.