Super CPC

dodogildo · 17:09, 17 February 16

You two are the hardware geniuses

If you can do it that small, then all of mortals would be more than happy!

ukmarkh · 17:18, 17 February 16

The only thing I can think, is adopt the latest Raspberry Pie?

I'm simply saying, we the creative juices of CPC WIKI, should be able to design a board, and come up with a design similar to the size and shape of the original CPC internal board. Then add things like more ram, clockable Z80 CPU, Parallel printer port, SD Card support, USB support and more. The CPC we've always wanted.

What's the point of a generic faceless box, when with the whole support of the community, we could set our sites 'RETRO'.

Fessor · 18:01, 17 February 16

If this faceless Box fits perfectly under the CTM like the MP-3 the PCB could be designed to have MX4-Expansion-Slots on board for future expandibility. Also there is no hassle with dust-protection and electromagnetic shielding and also place for a good PSU with enough current to operate all the electronics.

TotO · 18:05, 17 February 16

I dislike the idea to embed visible anachronous things.

almasys · 18:45, 17 February 16

Quote from: PulkoMandy on 07:07, 17 February 16
Here is something I did with a PCW motherboard and an old 5.25" SCSI drive enclosure, for inspiration.

Ok, but now you need a screen. How did you get an usable video signal... and which sort of monitor?

Thank you,
Mr. AMS

PulkoMandy · 20:49, 17 February 16

The video output from the PCW is usual 15.625Hz/50Hz. The only (but important) caveat is that the video signals comes straight from the PCW ASIC, and if you plug it to a standard TV with 75ohm impedance, the ASIC will overheat and burn. You need to protect it, I did that by running the video signals through a 74LSxx chip (anything will do: OR, AND, 2xNOT, ...). Then you can wire it to a SCART connector or to a DIN connector for the CTM640. You can check that the video display PCB of the PCW (not the motherboard) has such a buffer as well.

qbert · 21:04, 17 February 16

Very interresting, Pulko !

However... the PCW video mode is 90 columns wide : how does this look on a CTM640 ? Does the picture fill the left and right borders or do we have a stamp-sized 90 cols pictures in the middle of the screen ?

Bryce · 21:07, 17 February 16

My personal choice would be to use a PCB the size of the downsized 6128 PCB. You can easily fit a complete CPC and all the new expansions you could want on that and still keep the original ports and mountings compatible with a CPC case. I'd make all non-original expansions switchable, so that it would be possible to reduce it to a bare 6128 if wanted. I'd also keep the original keyboard interface, but include a PS/2 / USB port for alternative keyboards. It should include the orignal monitor port too, but also offer something more modern such as VGA or HDMI.

Bryce.

dodogildo · 22:27, 17 February 16

Yes, proper vga or HDMI please!!

Bryce · 22:30, 17 February 16

They're just my suggestions. I have no intention on working on such a project.

Bryce.

TotO · 23:24, 17 February 16

Quote from: Bryce on 21:07, 17 February 16My personal choice would be to use a PCB the size of the downsized 6128 PCB. You can easily fit a complete CPC and all the new expansions you could want on that and still keep the original ports and mountings compatible with a CPC case. I'd make all non-original expansions switchable, so that it would be possible to reduce it to a bare 6128 if wanted. I'd also keep the original keyboard interface, but...

Close to be OK, up to here. The Rev3 board mounting holes are not at the same place than Rev1/2.

Quote from: Bryce on 21:07, 17 February 16... include a PS/2 / USB port for alternative keyboards. It should include the orignal monitor port too, but also offer something more modern such as VGA or HDMI.

Not here. $:-\$
If the mainboard is used outside a CPC case, it is possible to connect a custom expansion board to provide the "modern" connectors required by users.

PulkoMandy · 07:08, 18 February 16

Quote from: qbert on 21:04, 17 February 16
Very interresting, Pulko !

However... the PCW video mode is 90 columns wide : how does this look on a CTM640 ? Does the picture fill the left and right borders or do we have a stamp-sized 90 cols pictures in the middle of the screen ?

It has smaller borders than the default CPC screen. The pixels are the same size as CPC mode 2 pixels, as the video timings are much similar.

Bryce · 09:48, 18 February 16

Quote from: TotO on 23:24, 17 February 16
Close to be OK, up to here. The Rev3 board mounting holes are not at the same place than Rev1/2.
Not here. $:-\$
If the mainboard is used outside a CPC case, it is possible to connect a custom expansion board to provide the "modern" connectors required by users.

Yes, you would either need both sets of mounting holes for compatibility or choose the layout that was most common.

As far as the new ports are concerned, that's a difficult one. Either an external module with the ports or choose free locations that would require some new holes to be cut in the case.

Bryce.

Munchausen · 10:23, 18 February 16

Quote from: Bryce on 09:48, 18 February 16
As far as the new ports are concerned, that's a difficult one. Either an external module with the ports or choose free locations that would require some new holes to be cut in the case.

I think just don't have a printer port and put as much as you can there before cutting anything. Who is printing from their CPCs these days anyway? If you want to have a digiblaster just make it internal.

gerald · 10:26, 18 February 16

Quote from: Munchausen on 10:23, 18 February 16
I think just don't have a printer port and put as much as you can there before cutting anything. Who is printing from their CPCs these days anyway? If you want to have a digiblaster just make it internal.

The printer port is a nice log port if you have the proper equipment connected to it (logic analyser, or dedicated usb logger)

Bryce · 10:27, 18 February 16

The printer port is very much underestimated as an expansion possibility on the CPC. At the moment there is only the DigiBlaster and an SDCard expansion released for it, but it has quite a lot of potential that may be used in the future. I'd keep it.

Bryce.

Munchausen · 10:44, 18 February 16

Quote from: Bryce on 10:27, 18 February 16
The printer port is very much underestimated as an expansion possibility on the CPC. At the moment there is only the DigiBlaster and an SDCard expansion released for it, but it has quite a lot of potential that may be used in the future. I'd keep it.

Bryce.

Sure, but you can have it internal. Currently there isn't much to use it for, and I don't like cutting holes!

Bryce · 10:55, 18 February 16

Well my plan was for the PCB to be mounted in an original CPC case, so the hole should already be there.

Bryce.

Munchausen · 11:05, 18 February 16

Quote from: Bryce on 10:55, 18 February 16
Well my plan was for the PCB to be mounted in an original CPC case, so the hole should already be there.

Bryce.

Sorry, I mean you can use it for other connectors so you don't have to cut holes for them. Actually, if you have most expansion you could want internally and spare MX4 connectors you arguably don't need the expansion connector either.

Anyway, just my thoughts.

Bryce · 11:10, 18 February 16

Quote from: Munchausen on 11:05, 18 February 16
Sorry, I mean you can use it for other connectors so you don't have to cut holes for them. Actually, if you have most expansion you could want internally and spare MX4 connectors you arguably don't need the expansion connector either.

Anyway, just my thoughts.

And where do I connect my original DKTronics expansions then!!

I see what you mean with the printer socket/hole, the idea isn't bad, but I would still prefer to have my original printer connector.

Bryce.

TotO · 16:06, 18 February 16

Quote from: Bryce on 10:27, 18 February 16The printer port is very much underestimated as an expansion possibility on the CPC. At the moment there is only the DigiBlaster and an SDCard expansion released for it

There is more interrest to free the printer port for new usages, than keeping it physicaly for that.

About the EXP and FDD ports, better to keep the edge compatibility and solder right angled pins over for peoples who wants to directly connect ribbon cables.

1024MAK · 17:31, 18 February 16

Err, has no one here heard about metal hole saws? They can produce suitable round holes (may need a round file to finish off).

True, other shapes are far more difficult.

Mark

1024MAK · 17:49, 18 February 16

Printer ports can be very useful for other things.
Not exclusive to CPC's, but in the recent past, I have used 8 bit computers with printer ports to test some intelligent LED display modules. To drive some latch chips to generate a 16 bit address bus to find the address decoding in an unknown interface. To act as a secondary status display to save leaving a VDU on. To feed a relay interface board (controlling a prototype robot). Oh, and for driving a dot matrix printer.

Just a shame Amstrad decided to use bit 7 to produce the /strobe signal. I would have used a pulse stretcher circuit fed from the click signal to the flip-flop (latch) chip (that forms the printer port "driver") instead. Then you could drive an older style LaserJet printer from it (the type that has a parallel port).

Mark

TotO · 17:54, 18 February 16

As you said, it is a shame that was a "7bit" port, because it is mainly useless.
All things you are speaking (led, robot, ...) can be acheived without any limitation on the expansion port. it was made for.

TotO · 22:48, 18 February 16

For more informations, I'm looking to see if we can put a cartridge slot in place of the printer connector.
The idea is to allow to play all the OLD CPC games converted in ROM for the "GX4000", on it.

(If all CPC can use this feature, it should be interresting to finally produre real cases for cartridges)

I'm not sure if the digiblaster is really used, but it should be embeded inside the main board by using a real DAC and mix it to the audio.
So, we don't waste this feature on the printer port... Just handle it in an other way.

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