Re: Zilog stopping Z80 production

Maybe China will make a clone...

a drop in replacement. If all I wanted was a machinery to run Z80 software my choice wuild be a RP2040 board.

Thank you both for your contributions. Although STM is somewhat better than BCM from my own perspective, both are appreciated by me.

Danke,

I miss playing with my old home built S-100 CP/M computer around 1980. Those were really the fun days of computing and digital logic circuits.

The other day after hearing the demise of the Z80, I ordered 2 of the

boB

It must be trivial to get a VHDL/Verilog model and make your own by now. The 6809 was my preference but took a few more years.

how much memory can it address?

Yes, I know. Address decoders are a dime a dozen (almost) and any other peripherals can either be made or, I may actually have the others laying around. I save old ICs and have since the 1970s.

Wasn't familiar with those 2. Yes, I would run out of code space with many micro controllers. The was always programmed in assembler and code was fairly smalll at that time. Amazing we were able to get along with less than 64K !

boB

boB

so in something like and FPGA in is with range of internal ram and memory speed is not really an issue

Yes. That's where I'd put a Z80 in the unlikely event that I wanted to use one these days. Along with RAM, ROM, and anything else it needs.

The interface isn't that complicated with parts that are available today to build something. OR I could just run the part at 4MHz.

I am not THAT interested in using an obsolete part. Just wanted one. I may never even use it.

boB

One reason I liked the 6809 was that it had 16 bit registers like the first CPU I ever used.

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.

I managed to factor numbers of up till hundreds of digits, using 1K of ram and 1K of videoram (that contained the digits) before this extension. No restrictions on the size of the factors! (Patience required.).

Groetjes Albert

Am 27.04.24 um 12:39 schrieb snipped-for-privacy@spenarnc.xsall.nl:

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'm pretty sure that was the situation. The machine served at a clair voyance test system, and the program (assembler) fitted in

Maybe the restriction was particular for this design. I have the machine still. Maybe I could modify it.

This was before CP/M.

Groetjes Albert