The Future-CPC# - CPC reborn - this is dedicated to the new CPC computer series.

[TFM]

This thread is dedicated to a new, overworked 2012 CPC using modern technology while staying compatible to the CPC6128.

You are cordially invited to this new born project. If you take part in it we will all together create a new CPC more powerful than ever.

For our Future-CPC# we ask for the following:

- Compatibility to the CPC6128

- Using the eZ80 as CPU (providing already TCP stack etc.)

- 4 MB of RAM (compatible to existing solutions)

- 1 MB ROM (sockets for Flash to enhance it to 4 MB if desired)

- As FDC we use the successor of the FDC765 (we can copy everything now)

- Additional Graphic Mode

- Additional Sound capabilities

- Mass storage (compatible to one of the existing systems for the CPC)

- Differrnt speeds (4 MHz, 16 MHz, 200 MHz - that's just the eZ80 without breaks)


For later stages of our Future-CPC# we ask for the following:

- Compatibility to the 6128 Plus in addition

- MP3 chip (allows to play MP3 sounds)


My contribution here will be project management and the code that allows the eZ80 to act as real Z80 (regarding I/O instructions).

[MacDeath]

mmm... perhaps you should also aim at the PLUS specs to begin with... oops my bad, you told this...

Is this thing supposed to have a real hardware ?


anyway, from what it looks, it is a continue from the PCW16 topic...

To me such kind of machine should have the real "retro Amstrad legacy"...
It means it should be retro-compatible with also ZX spectrums and PCWs... and ideally with PCW16 too...



a perhaps good way to assure a proper CPC/PLUS "emulation" would be to actually put a real Z80A on the thing.
so the more modern "reprogrammable big chip" would be used to get the CRTC-GateArray/ASIC/ULA/whatever emulation (and Memory mappings and so on...)

Those old Z80 can still be found I guess, and can be overclocked easily now.
a "legacy CPC mode" don't have to run too fast.


You know, those old arcade machines often had Z80 as a sound co-processor... so this machine could use the real "old" Z80 to run CPC/PLUS stuffs (legacy mode, fully ompatibility ).
Just like the way the Sega Megadrive used its "sound" Z80 to be retrocompatible with SegaMasteSystem...

And in "Fullpower mode", the Z80 could be used for the "Sound card"...

Extra bonus point if the thing also include a real AY...


Also, to get this compatibility you would have to get the same methode used by the PLUS to be retrocompatible... possibility to "lock" the extra stuff.

one issue is the way those old computers displayed on monitors...
They were "synched" with the monitor and designed on the CRT technology (now obsolete).

A modern approach would not go for this kind of monitor... but still you have to "emulate it" because the softwares were programmed with this in mind.



Concenring the video modes, it may depend a lot on what kind of monitor do you aim at.

While CRT was good for the varied pixels sizes and shapes, modern flat monitor are 1 pixel = 1 pixel... no more scanlines and so on... no more blurry round pixels...

Also the monitor Ratio changed a lot, from 4/3 to 16/10 or something like that...
And there is no more such thing as "Overscan zone"...

[TFM]

Let's stay realistic!

The "Eierlegende Wollmilchsau" is a nice dream here. But since the Future-CPC# will be real hardware and not an emulator, we have to focus on the CPC range of computers.

Components of the real CPC (CRTC, PSG, PIO etc.) will be there for compatibility purposes for sure - in case they can't be put into an FPGA, but this will depend on the taste of the team here. However our aim is to reatain a very hig compatibility. On the other hand we will have additional advanced mode (speed, gfx, sound enhanced).

It also may be worth condering PC components, since they are very cheap. But it this case IT IS VERY IMPORTANT to start with clear defined standards from the beginning.

You mentioned the kind of monitor, and that's indeed a very good point. It may make sense to move completely into the flatscreen are, since we can't buy anything else any longer. That should be discussed too.

[steve]

Regarding compatibility, do you think old software should run on the new machine (same speed or faster than CPC old)? or new software should run (slower) on the old machine?

The PLUS has it's incompatibilities with the CPC should we repeat these "mistakes", fix them (incompatible) or leave PLUS features out.

Instead of flash rom, you could have 8MB ram with the second 4MB block accessed as if it were rom, it could be loaded from disk as required or used as ramdisk.

If the firmware were rewritten to use the more powerful hardware it would run faster but may mean that some software runs too fast.

Formfactor, it could be a PCB that replaces the PCB in a CPC 464, or it could be designed as a second processor box that plugs into the CPC's expansion port, this eliminates the need for compatibility as you just switch off the 2nd processor when you want to run software that won't run on the 2nd processor.

24 bit pallette?, higher resolutions?

FPGA? could emulate SID chip, amiga sound or decode MP3.

The eZ80 can directly address 16MB ram this could simplify memory management, and give us more memory for the web browser.

[TotO]

Beter to begin with a simple question:
What do we want to do with a new CPC ?

[TFM]

I agree with your first mail. Some very good points there :-)

Compatibility mode = Yes!

Beter to begin with a simple question:
What do we want to do with a new CPC ?

That was always the hardest question ;-) Guess we want a CPC of 2012. Conserving all advantages and improving what we want.

[TotO]

Hard to keep the "CPC spirit" and not be borderline, when speaking "next cpc computer".
For me, a new CPC need to be the dreamed one in 80's, not today.

[steve]

Using the eZ80 the CPC# could be 50 times faster then CPC old, games will be unplayable without some speed control, new CPC# software will run too slowly on the old machines, so compatibility is compromised.

The firmware could be partially rewritten to use DMA to speed up disk access and manage 16MB ram as 4MB ram, 4MB write protected ram (rom), 4MB screen memory and 4MB ramdisk, although programs could be written to have direct access to 16MB ram, but would not be compatible with old CPC.

It is important to decide what level of compatibility is required from the CPC#

Beter to begin with a simple question:
What do we want to do with a new CPC ?

I would want more memory and faster speed to make internet access possible, new software is likely to be distributed this way and if the CPC# can get it's own software without needing a PC then that would be one less machine on the desk.

[TotO]

MAY BE A SURVEY ABOUT THAT ?

For you, a new CPC have to be :
- Enough powerful to be a PC desktop replacement.
- The CPC+ that we never get. Shame on Amstrad.
- Just improvements like Ethernet, Bryce stuff, but embedded.
- Not needed. I use my CPC for what it is.

[steve]

OK. For your use, it's a PC replacement with dedicated software.
Thank you.

NO,NO,NO that sounds like I want something that does everything the PC does and that is not the case, I simply want a machine that can download new software as that is how it is distributed now (cassette and disk versions are limited time offers).

[TotO]

I simply want a machine that can download new software as that is how it is distributed now (cassette and disk versions are limited time offers).

Sorry, I missunderstood. My post was edited.
Thank you.

[ivarf]

MAY BE A SURVEY ABOUT THAT ?

For you, a new CPC have to be :
- Enough powerful to be a PC desktop replacement.
- The CPC+ that we never get. Shame on Amstrad.
- Just improvements like Ethernet, Bryce stuff, but embedded.
- Not needed. I use my CPC for what it is.

For me
- Not needed. I use my CPC for what it is.

or an 8-bit Amigabeater that thrashes the Amiga 1200

[ukmarkh]

Wasn't someone working on such a project a while back now... the CPCNG???


It looked like an amiga 1200, with SD and CD-Rom, and used the EZ80?...

[Gryzor]

While the discussion is really interesting, I do fear (as most of us do, I guess) that practicalities will be the big obstacle; who will design the hardware? Who will manufacture it? What price are we aiming for?


These are rather basic questions, otherwise it just stays an academic exercise from start...

[ukmarkh]

While the discussion is really interesting, I do fear (as most of us do, I guess) that practicalities will be the big obstacle; who will design the hardware? Who will manufacture it? What price are we aiming for?


These are rather basic questions, otherwise it just stays an academic exercise from start...

What's wrong with the old en's?

[Gryzor]

My en's are just fine. It's my em's and pi's that have the occasional problem.


What do you mean?

[TFM]

Hard to keep the "CPC spirit" and not be borderline, when speaking "next cpc computer".
For me, a new CPC need to be the dreamed one in 80's, not today.

Agreed! However, it will be hard to get 20 MB MFM hard-discs, Sony-Trinitron 3D monitors, 8 kB chips for the O&F RAM disc... What i try to say is we will need to use some modern hardware parts, but this must not necesserily kill the CPC spirit.

And it's a good idea to remember the dreams we have had in die 80ies, 90ies about our dream CPC!

About the eZ80: If it runs at 50 MHz then it's 200 times faster then a 4 MHz Z80 (IIRC). Therefore we will have the previously described speed modes (4 Mhz, 16 MHz and full. In case... also 6, 8, ...).

DMA access will not significantly speed up floppy-disc access at all (since the disc itself will still rotate at 300 Upm). But it may be useful for memory-move actions. This speeds up GFX.

The enhance GFX mode should not be choosen to extreme. I would suggest 256 colors (1 Byte per pixel). And maybe a resolution of 720 * 256. This is already 180 KB!!! Maybe 320 * 200 would be better (equals about 64 KB). Or both modes.
Why a relative small resolution? Because the bigger the screen RAM is the longer it will take to draw GFX. The CPC is actually a perfect choice between quality and screen RAM size.

[robcfg]

All the suggestions are nice, but I think it's all a bit pointless because it wouldn't be a CPC anymore.


And also, you can buy a very cheap raspberry Pi and do all that things you without going through the hell of designing a hardware that would be in the end more expensive (Atari Coldfire anyone?).


That's my two cents.

[beaker]

The Pi is a lie... at least that's the conclusion I am coming to after my 5th email telling me my order of Pi has been further delayed... 

[steve]

What ever the resolution, it should still be viewable on a real CPC monitor.
Could the original ULA be used to generate 640 x 200 x 16 colours?

[dragon]

He can be designed as snes estile?.


So you can expand in a future the new cpc with a extra chips.As estile fx in snes,dsp-1 etc etc.... Via expansion port.


This can be made the new cpc expandable in the future.without remade the hardware.

[TFM]

All the suggestions are nice, but I think it's all a bit pointless because it wouldn't be a CPC anymore.

No it will be no original CPC from Amstrad. But it will be a computer very, very close to the CPC. And I suggest it to have all the ports that a 464 and 6128 (Plus?) has. So all CPC hardware expansions will be able to run. However some will not be needes since the CPC# will contain it internally (RAM, ROM, etc).

What ever the resolution, it should still be viewable on a real CPC monitor.
Could the original ULA be used to generate 640 x 200 x 16 colours?

Surely we will have compatible resolutons. In "compatibility mode" the CPC# will work 99% (our aim ;-)) like an original CPC.

The Gate Array and the CRTC can be completely simulated in FPGA. In the eastern German clones of the CPC the simulated the Gate Array by using standard IC's. So this part shouldn't bring bigger problems with it.

He can be designed as snes estile?.
So you can expand in a future the new cpc with a extra chips.As estile fx in snes,dsp-1 etc etc.... Via expansion port.
This can be made the new cpc expandable in the future.without remade the hardware.

Good point. We try to create the concept in a way that allows us to have an open, expandable system. Either using a special array for extension cards or maybe by a moduar design in principle. We can think about the best idea.

[steve]

 
Surely we will have compatible resolutons. In "compatibility mode" the CPC# will work 99% (our aim ;-)) like an original CPC.

The Gate Array and the CRTC can be completely simulated in FPGA. In the eastern German clones of the CPC the simulated the Gate Array by using standard IC's. So this part shouldn't bring bigger problems with it.

Using the CPC monitor would remind us not to stray too far from the CPC ideal, if we could use the old ULA we would not need to develop a new FPGA.

 
Good point. We try to create the concept in a way that allows us to have an open, expandable system. Either using a special array for extension cards or maybe by a moduar design in principle. We can think about the best idea.

We could give it expansion slots like those in the Apple II.

[TFM]

Using the CPC monitor would remind us not to stray too far from the CPC ideal, if we could use the old ULA we would not need to develop a new FPGA.

Do you know any soure for the ULA / GA ?

We could give it expansion slots like those in the Apple II.

Uups, maybe it should at least something ECB like, and we actually could stay even CPC exp-port compatibel - maybe with a second set of pins with signals needed for DMA and so on.

[ralferoo]

Well, I seem to be going in a completely different direction to your vision, but anyway, here's a picture of what I've been working on for the last couple of weeks...


http://ranulf.net/homeboard28.png

I'm about to get a couple of boards made up to test, I'll obviously post pictures here when it's all up and running.