New yerar, new CPC board

[Joseman]

Still, it's a rather neat solution.

Bryce.

Do you think that is recommend to do this from the start on a new cpc board?

i mean, the compatibility is 100% accurate with cpc software-games?

I don't deny that 256kb accessible by the CRT is very interesting...

[gerald]

Do you think that is recommend to do this from the start on a new cpc board?

i mean, the compatibility is 100% accurate with cpc software-games?

I don't deny that 256kb accessible by the CRT is very interesting...

Only the base 64k are usable for the video, see the note below the equations.
When the GA has access (CPU signal high), all address comes from the CRTC (externally muxed) and the new address (AMUX)  bit is forced.

From a compatibility point of view, only the basic scheme are there : C0, C4,C5,C6,C7.
You cannot switch the whole 64k (C2), nor use the C1,C3 mode (extension RAM mapping at 0xc000)
Also, SW using the C1,C2,C3 will indded activate an extension ram mode, but not something expected 

[Bryce]

Do you think that is recommend to do this from the start on a new cpc board?

i mean, the compatibility is 100% accurate with cpc software-games?

I don't deny that 256kb accessible by the CRT is very interesting...

No. It doesn't really have any huge advantages. We should stick to the current standard to keep compatibility.

Bryce.

[Joseman]

Ruled out this add-on then! 

[Bryce]

Ruled out this add-on then! 

As it's (almost) just a plug-in and relatively cheap to make, you could make one up and test it pretty easily and then remove it again if it's not to your liking.

Bryce.

[Piotr]

Hmm, i specially made Just CPC in THT, all IC is socketed for "easy" changes, modifications ,add ons etc.

[Bryce]

The original 6128 has the PAL socketed too.

Bryce.

[Joseman]

and that's one of the many reasons why i like so much it!!

[Piotr]

Small board for this German expansion to 512, U1 GAL, U4 2x10 pinrow to fit it in old gal socket.

[Bryce]

Nice. If you overlap the PAL socket/pins and rotate them 90° the PCB would be quite a bit smaller.

Bryce.

Edit: Can you share the files? I'd like to try out a few different layouts.

[Piotr]

Yop Bryce, i do it quickly just  for example, in 20 minutes. Still need some work,  dimensions etc.

Sure i can, but i working on Diptrace

[Bryce]

Thanks, I don't usually use DipTrace, but I have it installed. Good time to learn to use it better

Bryce.

[Piotr]

Have fun, but is a really user friendly soft And free up to 500 points i think?

[Bryce]

Yup seems pretty intuitive. Here's my suggestion, something like this. I've flipped the smaller IC over onto the bottom along with the resistors and 2 caps.

Bryce.

[Bryce]

Or (easier to route), double sided but with ICs on the side.

Bryce.

[gerald]

Or (easier to route), double sided but with ICs on the side.

It would be better to have the smd IC on the other side of the PAL. That side is free of component on the main board.

[Bryce]

Yes, I didn't check how it fits in the CPC, it was just a layout concept to see how small it can be squeezed. The header is probably on the wrong side too?

Bryce.

[gerald]

It would be better near pin 1 : IC114 is under the PAL, the RAM and IC109 on the right.

[Piotr]

Diptrace sometimes do a bad joke and if you flip IC for bottom side PCB don't change pinout so be careful.

[Piotr]

dOk, on the way DHL from China.

[skywalky]

I like it, and I want one soon.

[CraigsBar]

All these pictures that tease lol. Is the only difference between the 128k and 64k models, other than the extra ram bank obviously, the extra m4x slot? If so that will be a tough decision once these become available!

[Piotr]

Well

[CraigsBar]

Well

That looks awesome[emoji3]

[Joseman]

That looks awesome

indeed