Design your own 20MHz Z80 microsystem.. MTX PLUS !!

lezanderson
Posts: 186
Joined: 14 Aug 2012 15:31

Design your own 20MHz Z80 microsystem.. MTX PLUS !!

Post by lezanderson »

I've got some FREE Z80 stuff :

Z84C0020 20MHz CPU DIP40
HM628128 128k byte SRAM 55ns DIP32
W27C512 64k byte EEPROM 45ns DIP28
V9958 VDP DIP64
20MHz crystals
21.4772 MHz crystals
EPM7128 CPLDs PLCC84
GAL22V10 SPLDs
MAX232 RS232 Drivers
Various other ICs
DIP16/DIP18/DIP20.....DIP28/DIP32/DIP40/DIP48/DIP64 IC sockets
PLCC sockets ,32,44,52,68,84


Just send a SAE (stamped Addressed Envelope ) to me :

Lez Anderson
4A Wells Grove
Willington
Crook
County Durham
DL15 0PS
United Kingdom


And I'll send you a FREE kit...

I'll be posting on the FORUM a CRASH course on how to design a BASIC Z80 MTX type system over the next five weeks or so. It's an ideal way to learn about Z80 hardware and microcomputer design.

http://memorum.mtxworld.dk/posting.php?mode=post&f=8#
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Crazyboss
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Re: Design your own 20MHz Z80 microsystem.. MTX PLUS !!

Post by Crazyboss »

sounds good, but how can it be free ?
Did you seal those components somewhere ? :lol:
//CLAUS - Webmaster at www.mtxworld.dk
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Dave
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Re: Design your own 20MHz Z80 microsystem.. MTX PLUS !!

Post by Dave »

Hi Lez,

that's a very generous offer - too good to pass up, count me in please!

Given the Royal Mail's somewhat complex pricing structure these days, have you any thoughts on how big an envelope and how much postage to send to cover the mail charges?

regards
Dave
lezanderson
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Re: Design your own 20MHz Z80 microsystem.. MTX PLUS !!

Post by lezanderson »

Crazyboss wrote:sounds good, but how can it be free ?
Did you seal those components somewhere ? :lol:

These are mainly stuff I've gathered over several years and have no further use for.. Just send a stamped address envelope with about £3.70 worth of stamps on it or so and I'll post you one ..

I recently send a kit to Germany and it cost £3.70 in postage !

When things are FREE...don't ask silly questions !!


..I won't be supplying any copper boards to etch... as these are quite expensive, it's messy and time consuming making your own boards and larger complex boards tend to go wrong anyhow !! So it works out easier and cheaper to just get a prototype one made for about £15-£20..
lezanderson
Posts: 186
Joined: 14 Aug 2012 15:31

Re: Design your own 20MHz Z80 microsystem.. MTX PLUS !!

Post by lezanderson »

Dave wrote:Hi Lez,

that's a very generous offer - too good to pass up, count me in please!

Given the Royal Mail's somewhat complex pricing structure these days, have you any thoughts on how big an envelope and how much postage to send to cover the mail charges?

regards
Dave

Send an A4 size jiffy bag or a small cardboard box... anything up to 750g is £2.20 second class UK, £3.70 first class UK. To post to Europe is about £3.70
lezanderson
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Z80 Microcomputer Design --- PART 1 postpones for two week

Post by lezanderson »

Hi.

I've decided to postpone the Z80 course for TWO weeks to see if there's more interest...!

I'm also producibng a draft document as a course companion...so we can muddle our way through it better..... I hope.

This will include a week by week guide and schematics for parts like the V9958 and sound generator..


Best Regards

Lez
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Dave
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Re: Design your own 20MHz Z80 microsystem.. MTX PLUS !!

Post by Dave »

Hi Lez,

just a couple of questions in the meantime then........

Are you intendiing that the design include interfaces to readily available hardware, i.e, VGA (or HDMI) monitor, PC (PS/2 or USB) keyboard, file storage (USB or SD card) etc. etc.?

regards
Dave
johnha
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Re: Design your own 20MHz Z80 microsystem.. MTX PLUS !!

Post by johnha »

Hi All,

I get the impression this project has stalled? If so how far did it get?

I have been interested in developing a micro from scratch and this project might be something I'd consider looking at (although I'm thinking a 'generic' Z80 based system is more practical than a 20MHz MTX...).

A few thoughts:
- Assuming a low unit count, wire-wrapping might be more appropriate than using a PCB (easier to get started and easier to modify). Note this is very much 'theory' (I have no idea how practical it would be in reality).
- Ideally, modern interfaces would simplify things assuming the drivers were a) suitable to be interfaced to a Z80, b) cheap/practical enough to use (i.e. preferably not surface mount or 3.3v) and c) match the performance of the Z80 (what kind of resolution would be expected with HDMI that a Z80 could drive?).
- What was intended as far as the ROM was concerned?
- Power supply?

Obviously, if it uses too many modern interfaces/components, it starts to look a lot like Andy's ReMEMOTECH (there's little point duplicating that work) or an emulator on something like a Raspberry Pi. At some point the effort/resources may be better used on something else.

John.
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Dave
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Re: Design your own 20MHz Z80 microsystem.. MTX PLUS !!

Post by Dave »

Hi John,

The original idea that Lez had for a group of Memotech enthusiasts developing Z80 systems did stall. I think I was the only person on here that was interested in doing it, most folks here are pretty much software orientated. There is a similar thread on a Tatung Einstein forum which did seem to generate a bit more support though.

Similar to yourself, I was/am interested in the challenge of building a micro from scratch, it was/is going to be a bit of a challenge! Les did sent me a couple of "installments" of his material, as well as lots of IC's etc., so I am still planning on going ahead. I did mean to make a start over the holiday period, but didn't quite make it! I do intend to make a start soon though, I have been gathering quite a bit of technical data and posting it on my site.

If you like, I can send you a copyof the material that Lez sent me?

As you say, one of the challenges is the PCB manufacture, although I don't think that wire wrapping appeals to me, there are quite a number of home brew Z80 systems on the web that use breadboards with hard wiring, so it's obviously do-able.

As far as te ROM is concerned, that was to be another challenge, writing your own! So, learning not only Z80 hardware design, but Z80 assembly language too :-)

Regards
Dave
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