CTC-AY, a new CPC expansion board!

[Gryzor]

From here: RetroManiac | Revista de videojuegos retro |Videogames Magazine | Indie | Games


Apparently it incorporates a twin AY chip for multi-channel symphonic sound AND a ROM that can be programmed from the CPC with cartridge images and boot from it


Can't wait!!! By only concern is it doesn't seem to have a pass-through connector and thus one will have to remove existing expansions to use it...

Some more info (Push'n'Pop | Amstrad CPC Demoscene | CTC-AY Expansion Board):

Audio:
• 2x Yamaha YMZ294 (AY compatible) on custom ports (no PPI)
• Add 3ch Left / 3ch Right with speaker mono mix and stereo mix output

Counter/Timer:
• Z80 CTC (4MHz) with vector interrupts handling (IM2)
• Programmable audio clock (CPC, ZX, ST, ...)
• CRTC cursor signal can trigger /NMI
• A 16bit general purpose Timer

Cartridges Slot:
• Up to 2MB Flash ROM on pages 128-255 ($DFxx)
• Lower & Uppers are programmables from CPC
• Auto-boot support
• Optional 8KB saves (w/o battery)

Other:
• Bus reset button
• Soft reset friendly ($F8FF)

[Bryce]

No pass-thru connector isn't an issue. You should be able to connect other expansions in parallel with the appropriate cable, however connecting another ROMBoard or expansions which have an internal ROM (such as the DDI-1) would be a bad idea.

Bryce.

[Gryzor]

Didn't know about running them in parallel, which is cool; but I kind of guessed there'd be problems with the boards I've got from you


Maybe someone could build a splitter with a disable switch? Possible?

[arnoldemu]

I was waiting for this to be announced!

I haven't tried it yet, but I can see it's a great piece of hardware.

I will support it in my games.

[Sykobee (Briggsy)]

Well this looks like it is going to be a nice piece of hardware, and not only for the 1/2/4MHz dual-soundchips.


The timer/counter looks to be a very useful feature, allowing far more fine grained control over things including the CRTC. It will be interesting to see demos in a year or two once programmers have got to grips with it.


How is the internal CPC audio mixed with the CTC-AY audio?

[arnoldemu]

Using the cursur interrupt gives you precise control over the crtc.

[Bryce]

Didn't know about running them in parallel, which is cool; but I kind of guessed there'd be problems with the boards I've got from you


Maybe someone could build a splitter with a disable switch? Possible?

You'd only need to switch the ROMDIS signal between the two devices, so it should be quite simple to do.
This new device more or less covers the functionality of the LowerROM and MegaFlash, so there's no real point in connecting any of my stuff at the same time.

Bryce.

[fano]

Can't wait!!! By only concern is it doesn't seem to have a pass-through connector and thus one will have to remove existing expansions to use it...

Nope, it works perfectly with CPCbooster+ (for devellopers it is highly recommanded to write cartridges directly from a PC without manipulations) and FlashGordon romboard.About DDI-1 , ROM may be not a problem as CTC-AY roms are mapped from 128 to 255, i'll check that with my 464.

[Gryzor]

This new device more or less covers the functionality of the LowerROM and MegaFlash, so there's no real point in connecting any of my stuff at the same time.

Yes there is: my CPC looks damn fine with all those things hanging about

[rexbeng]

Well, personally I find the most important aspect to be the cartridge slot because it solves every single issue concerning data medias: 3'' disks are getting rare, old and tired and so are their drives (I dare not speak of tapes even ). Cartridges mean you can make games that can be as big as you like them to be, carry all the content you want them to have, not having to worry about loading, disk/tape speed, avalable memory (464 vs 6128) etc.


So, since I've gotten into developing games again thanks to Axelay, it's often that I came across issues like those described above and I kind of *wished* for somethig like this for years.


I have occasionally been throwing banana skins in hardware discussions on CPC sites, asking hardware developers if and how a cartridge could become reality on the CPC. Not just a "rom (for board)", but something that I can take out of one box, plug it in my CPC and boom; game runs without you needing to run any tools, make any file transferts and so on...


One day someone slipped on one of those banana skins. Thank you Chiquita!


rb

[TotO]

Hey Gryzor!

Sorry, if I have not contacted cpcwiki, cpcrulez and others about the information.
We have worked hard in secret to make possible to show it at the ReSeT #10.
Thank you for the topic, it will be nice to speak about it.
It's actually in Developer states and work fine. (just a little audio mixing problem to fix)

So, I start the "FAQ" here, looking yours pertinent questions:

Q- Why there is no passthrough connector on it?
A- It's complex to root all the bus on both sides on a 2 layers board. But, a multi connectors ribbon cable work.

Q- Is the CTC-AY compatible with others boards w/o conflict?
A- Yes. The CTC-AY use it's own ports and the $DFxx standard GA port.

Q- Can I continue to use my existing ROM board with the CTC-AY?
A- Yes, if your ROM board fully decode the ROM ID, because the CTC-AY cartridge slot is mapped from 128 to 255.

Q- How are mixed the audio channels?
A- 3 left, 3 middle (AY), 3 right

To be continue...

[Gryzor]

Hey, of course no need to apologise, it's not like the Wiki has the exclusive right to announce projects


Thanks for the details, looking forward to moar!

[TFM]

So finally the great and well hidden secret comes out   
Yes, you can use it with other expansions. 
And of course I will support it with my productions.  [nb]@TFM: For wasting too much smileys your beer will be replaced by milk! Aaaaaaaaaaaaaahhhh![/nb]

[Bryce]

Q- Can I continue to use my existing ROM board with the CTC-AY?
A- Yes. The CTC-AY cartridge slot is mapped from 128 to 255 when ROM Boards are 0 to 32.

That's a bit of a generalised comment and I doubt it's correct. Although some ROMBoards fully decode the ROM Number on the data bus, some cheaper (and/or badly designed) ROMBoards didn't and replied (and set ROMDIS) no matter what ROM number you had chosen. These boards definitely won't work with the CTC-AY. They will most likely cause the CPC to crash. The MegaFlash fully decodes the data bus, so it shouldn't cause any problems with the CTC-AY.

Bryce.

[TFM]

Q- Can I continue to use my existing ROM board with the CTC-AY?
A- Yes. The CTC-AY cartridge slot is mapped from 128 to 255 when ROM Boards are 0 to 32.

The 6128 Plus also occupies ROMs from 128 to 255. So I assume if a ROM board works with the Plus, it will also work with CTC-AY.

[IanS]

You'd only need to switch the ROMDIS signal between the two devices, so it should be quite simple to do.
This new device more or less covers the functionality of the LowerROM and MegaFlash, so there's no real point in connecting any of my stuff at the same time.

Bryce.

Did you really mean ROMDIS? Two devices that responded to the same rom number would still put the data on the bus at the same time. ROMDIS just tells the internal rom to not be enabled. I would have understood if you switched ROMEN between multiple devices.

[TotO]

That's a bit of a generalised comment and I doubt it's correct. Although some ROMBoards fully decode the ROM Number on the data bus, some cheaper (and/or badly designed) ROMBoards didn't and replied (and set ROMDIS) no matter what ROM number you had chosen.

OK. I will complete the answer.
Thank you.

[TotO]

The 6128 Plus also occupies ROMs from 128 to 255. So I assume if a ROM board works with the Plus, it will also work with CTC-AY.

That was probably a good test, yes.

[SyX]

Nice video of fano burning a cartridge using the CPC Booster:

Burning CTC-AY Bios in 1 step with CPCbooster+ Bluetooth

[Bryce]

The 6128 Plus also occupies ROMs from 128 to 255. So I assume if a ROM board works with the Plus, it will also work with CTC-AY.

The Plus handles the cartridges completely different to how external ROMBoards work, so the answer is no. These older ROMBoards would work perfectly on a Plus, but still have problems with having another ROM enabling piece of hardware on the expansion port.

@IanS: Yes, I meant ROMEN, the brain was in idle when I typed that one

Bryce.

[TFM]

Completely different?    If you say so...

[Bryce]

Yes, completely different:

External ROMBoards are enabled using ROMEN (plus the Data sent to DFxx) and they confirm this request with ROMDIS. On the plus, neither of these signals go to the cartridge port, it has it's own signal called ROM. So a cartridge shouldn't clash with a ROMBoard.
On the Classic CPC, ROMEN is produced by the Gate Array and ROMDIS is a direct connection to the internal ROM0. On the Plus, all 3 signals ROMEN (pin 133), ROMDIS (pin 129) and NROM (pin 29) are handled by the ASIC.
On the CTC-AY the ROMs, although mapped to the same ROM numbers as a cartridge are still handled like standard ROMs using ROMEN and ROMDIS.

Bryce.

[Axelay]

Yes, completely different:

Funny you should say that, because after reading what followed, my brain hurts! 

[TFM]

Oh, well, I was more referring to the practical behaviour. However let's go back to the topic. What we know it that expansions like MegaFlash, ROM-RAM-Box, SF2 and Dobbertin-Eprom card are compatible with the CTC-AY.[nb]There may be few partial decoded old fashioned EPROM cards out there, but probably in quantities which can be ignored.[/nb]

[fano]

You forgot the FlashGordon