Path: csiph.com!news.swapon.de!eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Bozo User Newsgroups: comp.os.cpm Subject: Re: The ideal standalone Z80-based retro computer Date: Sun, 30 Jul 2023 18:53:03 -0000 (UTC) Organization: A noiseless patient Spider Lines: 22 Message-ID: References: <0b23887c-d521-4424-8e62-8758cb92c763n@googlegroups.com> <227e7d81-50fa-42e2-bf7a-ea8907ebe73an@googlegroups.com> <182c1c4f-e39a-459b-87a7-dc0c338122ecn@googlegroups.com> Injection-Date: Sun, 30 Jul 2023 18:53:03 -0000 (UTC) Injection-Info: dont-email.me; posting-host="750b7ead907a82b023e3008a15a34892"; logging-data="3161162"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18sapgeMwpa9eMmbQ+mol/q" User-Agent: slrn/1.0.3 (OpenBSD) Cancel-Lock: sha1:sEmwVxDs4M9S2/GEoHwehrUxhpE= Xref: csiph.com comp.os.cpm:13847 On 2023-07-25, Roger Hanscom wrote: > I've designed and built a couple of standalone Z80 based SBC's: > > One is quite small (maybe 4.75" x 3.75"). It runs at 20 MHz with a full sixteen 8 MB "disks" on compact flash. It has two serial ports running at 115k baud (one used as a console) via a Z84C4010PEC. It uses a 128k x 8 SRAM. The two 64k x 8 halves can be accessed, but I haven't experimented with bank switching at all. It has a 32k x 8 ROM that contains a monitor, a CP/M 2.2 image, and some utilities. The ROM can be switched out of the memory map for a (roughly) 55k TPA. The most interesting part of this SBC is that it can be completely powered from the USB adapter that is the console. The downside (for some) is the use of a half dozen surface mount 74LS chips. I've collected a fair number of the old Z80 compilers and got them running (BASIC, C, PL/I, Pascal, and FORTRAN). It is amazing that these compilers that were so painful to run at 4 MHz, are *very* usable at 20 MHz! > > The second is quite a bit larger (maybe 5" x 7"). Same basic features of the Z80 described above, but this one uses a Z85C30 UART for two serial ports (one used as console). It is fully through hole 74LS, and has a fully TTL compact flash interface. It can be configured for 32k or 16k banks (using a 512k x 8 SRAM), but again I have not done much with that. It has a DS1302 RTC (battery backed). It also has a native USB port based on the DLP-USB245R that is amazingly fast! Again, a monitor, CP/M 2.2 image, and a number of utilities are stored in a 32k ROM that can be switched out of the memory map. > > I'd post photos of both of these Z80's, but I can't see a way to do that here. > > As is usually the case, the price of function is complexity, so some of the "wish lists" posted here would possibly have to be constrained by that old adage! > > Roger Would a 20MHZ z80 (or more) be able to play Zmachine games (z5 and z8 version) with enough speed? I think the 6502 on the C64 with a REU it's able to play Z5 games with a few seconds delay and Z8 games run very slow. You know, the interpreter to run Infocom games, but there are several "amateur" (not so amateur since the 1993's game 'Curses!'). games to try. Bear in mind Z3 games will run fine in any 8bit machine, but for Z8 games a 286.386, or 68k machine it's expected.