Path: ...!weretis.net!feeder9.news.weretis.net!news.misty.com!2.eu.feeder.erje.net!3.eu.feeder.erje.net!feeder.erje.net!weretis.net!feeder8.news.weretis.net!reader5.news.weretis.net!news.solani.org!.POSTED!not-for-mail From: Jan Panteltje Newsgroups: sci.electronics.design Subject: Re: Zilog stopping Z80 production Date: Sat, 27 Apr 2024 14:32:57 GMT Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; ISO-8859-15 Content-Transfer-Encoding: 8bit Injection-Date: Sat, 27 Apr 2024 14:32:58 -0000 (UTC) Injection-Info: solani.org; logging-data="95506"; mail-complaints-to="abuse@news.solani.org" User-Agent: NewsFleX-1.5.7.5 (Linux-5.15.32-v7l+) Cancel-Lock: sha1:OmQewmE/GD/EnmA/Lgf9oAAxr4o= X-User-ID: eJwNy8kBwCAMA7CVcjmBcVyo9x+h1V/I9j5TjS4I4r1PjTlhHLbzxSm1jLYjWJNefwGbPmu4cc+ShNxc4fEBVE8VHw== X-Newsreader-location: NewsFleX-1.5.7.5 (c) 'LIGHTSPEED' off line news reader for the Linux platform NewsFleX homepage: http://www.panteltje.nl/panteltje/newsflex/ and ftp download ftp://sunsite.unc.edu/pub/linux/system/news/readers/ Bytes: 3128 Lines: 46 On a sunny day (Sat, 27 Apr 2024 13:57:05 +0200) it happened Gerhard Hoffmann wrote in : >Am 27.04.24 um 12:39 schrieb albert@spenarnc.xs4all.nl: > >> Motorola was much better in this respect. Peripherals are accessed >> by handshake. So you could put a longer delay iff the peripherals >> are slow. >> >> I remember spending 2000 guilders in around 1980 for 16 K ram >> for my Z80. >> Just to discover that code in this ram couldn't run, because the >> Z80 was too slow. Only useable for data. > >The other way around. The RAM cycle time was too slow for the >Z80 because of the DRAM refresh cycle after the instruction fetch. >And there was a /wait input on pin 24 if your bus logic was >unable to keep up with the Z80. Looks like handshake for me. > >My first 64K*1 DRAMs did cost DM 64,00 each - which was quite a >sensation (NEC or Hitachi). And of course, my system got >the the first usable 8" DSDD floppy drives and ran CP/M. >I'm pretty sure that the instructions were in DRAM. >There was no ROM after booting at all. > >I did the CP/M port with a friend. It later turned out that >the Altos computer was near identical, just patching the >I/O addresses would have been enough. >Later I even got a 1MB RAM floppy, powered by 8086. >(really to do a paid CP/M-86 port :-) > >regards, Gerhard I used 5 1/4 inch floppies in Kaypro2 format added a 256 kB RAM disk addressed by the Z80 I/O instuctions. Added a 'copy floppy to ramdisk' command, and could run from there. No seek and no r/w times times. https://panteltje.nl/panteltje/z80/system14/diagrams/index.html scroll down to Ramdisk card: diagram part 1 diagram part 2 component layout timing waveforms Wrote my own CP/M clone.