Designing and building the KCC plus, a new, enhanced CPC6128 compatible computer

[Benedikt]

This thread is about my recently started long-term project: The construction of a new, enhanced CPC6128 compatible computer that is loosely based on the schematics of the KC compact.

The rationale behind basing the new machine on the KC compact is that it managed to achieve a very high level of compatibility exclusively with standard components from that era.
There is therefore no need to slaughter a CPC for its gate array, nor is there any need to resort to spooky alien technology from the future, such as FPGAs or 32-bit microcontrollers.

My ideas for the for the system's overall specifications are that

• Everything should feel like a well-balanced, natural evolution from the classic CPC product line
• The system should be roughly twice as good in every way, possibly better

I therefore came up with the following goals

• Between 256 KiB and 1024 KiB of RAM, ideally as a pair of SRAM chips
• Two AY-2-8910 PSGs for additional polyphony and additional control lines, on-board Digiblaster
• 16 bit data path for pixel generation and duplication of the relevant logic for twice the color depth
• Bypassable EGA-like latch in the second RAM chip's data path to keep block fill/copy operations fast
• At least one attribute mode, e.g. for colorful high-res pseudo text modes
• The Plus-series' connectivity, but keep the KC compact's SCART port and bi-directional 8-bit printer port
• Ideally some way to optionally double the CPU clock and/or FDC clock, if feasible
• Internal IDE and Serial ports, if it fits
• The CPC6128's form factor: System board should fit inside a German CPC6128 case
• High quality keyboard with n-key rollover
• Design for a laser-cut case, e.g. for a painted plywood case

To maximize the benefit for the broader CPC community, as many parts as possible should also be usable to fix or enhance existing CPCs.

The current state of affairs is that the keyboard assembly for the KCC plus is ready. It will get its own thread, because I reckon that it will be particularly useful for CPC users.

The next step is to design evaluation boards for various parts of the system, such as clock generation, audio, RAM, pixel generation, storage etc.
These will initially connect to a CPC and, where feasible, will be designed to be usable as CPC expansions.

Please share your thoughts!

[cwpab]

While I'm not among the potential customers for this kind of things, I love to follow the news on them as after all, they're pretty cool.

So a few months ago, I created a topic on this forum that can be very interesting to you, as it has a lot of ideas from fans like me and true experts:

Amstrad CPCnext: Would you buy one?

Also, it's great (and unusual) that you're "relatively new to the CPC world". Can you elaborate on that? I mean, you need to really like the CPC to create your project, but you apparently didn't have one in the 80s or 90s. What is exactly your story? What made you interested in Amstrad's machine? What is... the magic of the CPC?

(As a general comment, the Amstrad-related scene is amazing these days: several mdoern games look like Amiga games, one single Spanish guy created a Sensible Soccer clone, a GTA clone and a mode-7 demo, two more Spanish guys have just created a point & click graphic adventure... and now someone "new to the CPC" wants to build a CPC Next... what does the CPC have?).

[eto]

I love the idea. I'm personally looking forward to the new keyboard. 

The expansions should best be compatibly with already existing hardware, like the additional sound chip could e.g. be compatible to the PlayCity expansion.