New Plus Series Game a Proposal

[arnoldemu]

There is, but the guy who send me a copy told me to shut up about it. You know him probably better than I do.

The reason for the lack of physical Carts is only the lack of Cart Shells!

If it was me  then I don't like to show my games early because it takes me so long to finish them.
So I like to keep them quiet for a bit

[arnoldemu]

It does not have to be a cartridge does it though, make it a file a floppy emulator can use and programme it like the big software houses did in the early 90s, how did they get around the acid chip when putting disk games for the Plus range.

To play these plus disk games you need the system cart plugged in which contains basic, os, amsdos and an acid chip.

The games on floppy load up, unlock the extra features using the special code sequence and then use them.

If it's a real cart you need the case, rom and acid to be like the originals.

The code does a similar thing and normally the first thing it does is to unlock the plus features then use them.

There have been a few bootleg cartridges, but they hack an existing one and normally put a normal cpc game onto them.

[TFM]

... how did they get around the acid chip when putting disk games for the Plus range.

The ACID chip is a pure hardware protection, the machine just needs one.


Games on disc have no connection to the ACID, software is not able to sense it. Without the ACID the CPC couldn't start up (boot) anyway.


So Plus games on disc are "unprotected". Therefore Cartridges have been made.

[andycadley]

It does not have to be a cartridge does it though, make it a file a floppy emulator can use and programme it like the big software houses did in the early 90s, how did they get around the acid chip when putting disk games for the Plus range.

The problem with disc/tape games is that the whole organization of the Plus hardware is geared around the assumption you're running from a cartridge. It's not the most insurmountable problem in the world, but it does mean at various points you have to work against the hardware if you aren't. Copying sprite data into the ASIC from banked memory is a PITA, for example, whereas if you were copying it out of cartridge ram the paging just works better. Likewise being able to run code from a ROM but write straight through to display memory or a DMA buffer underneath gives you the impression of a lot more memory to play with than you'd otherwise get.

But yes, you probably could write a much more simple game and just put it in cart form for emulator users, but is there really much call for that when almost nobody can really play it as intended? Maybe I'll have a look into it, just to encourage those hardware boffins to try a little harder? ;-)

[ralferoo]

If anyone were to design a 512KB ram board they might also give it the ability to emulate a cartridge.

The interface for the cartridge slot is very different to the expansion port, so they'd have to be totally different designs.

[steve]

I was thinking that if the ram expansion was attached to the expansion port, it could either be addressed as paged ram or paged rom, if the cartridge uses the same paging mechanism as the expansion port then the ram should emulate the cartridge.

[TFM]

No, RAM is RAM. Sorry to say that very open: You got no idea how this all works. And I can't start from Adam and Lilith or Eve. So, just accept that it can't be done. And btw. a RAM expansion will never emulate hardware sprites or DMA sound.

[steve]

Ram is a memory chip, rom is a memory chip, they are both accessed by the memory bus they just have different paging schemes, let the ram be written using the ram paging mechanism, when the user wants to test a program he will throw a switch and the ram will be accessed by the rom paging mechanism, the processor is effectively accessing a rom, as they are both memory chips, just at different addresses.
I know it won't emulate sprites or dma sound, I never suggested it would.
This device will be connected to the plus expansion bus so those features will exist in the plus machine, I never suggested that this device would make a cpc the same as a plus, that would be ridiculous.

[andycadley]

The problems with that are:

1) Assuming you can override the internal behaviour, it's got to be more expensive in the long run to put all the paging hardware that already exists internally in your add-on device. Now that might be offset slightly by taking advantage of the CPC to program the device, but maybe not.

2) One of the reasons a developer wants a cart is to know the code they write works, regardless of the bugs that exist in the hardware (and there are already a fair few known bugs in the Plus hardware). An external paging device may well behave the way the Plus specs suggest, but not the way an actual Plus does.

3) You lose all the convenience of carts in the first place, not to mention the ability to play on the GX.

[steve]

If the cartridge uses the same paging mechanism as a rombox just (higher rom page numbers), then it should be as easy to make a cartridge emulator as it is to make a rombox, the device would be for program development, once it is debugged the program would be put in a cartridge.
Maybe the megaflash could be modified to use the same pages as the cartridge.

EDIT, I don't know if the flash chip can be written to like ram or needs a special writing circuit.

[TFM]

Look the Cartridge can page in ROM at all four blocks, RAM can't. And I don't assume you suggest to rewrite every game.

[steve]

Never mind.

[arnoldemu]

I get what steve is talking about. I think.

1. RAM which is mapped as ROM. Similar to Megaflash or Inicron's RAM-ROM etc.
So programs can write to this to initialise the data.

2. The ROM acts just like cartridge ROM. This will work.

No need for extra  hardware to simulate the plus.

This is a nice idea, but these are my thoughts.

I create code on the PC. Now what I would really like is a way I can connect the PC to a writeable cart.
I would turn off the Plus, switch the cart into write mode and the pc can send the data to it. The data is remembered. Switch the cart into read mode, turn on the Plus and see it working. USB would be best here for it to work, so the cart would need a USB chip, and some kind of CPU which can access the RAM. Problems here, the PC would need drivers to support this unless it looks like a memory stick - so this would be a problem.

The other alternative is a cartridge with a SD-Card, or usb socket on it.
When the cart is turned on there is a short delay while the on-board CPU downloads the data from the sd-card/usb stick and writes it into the cart-ram. CPC then executes it.

All of these would need some software writing to work, the last is probably "easiest" because you would not need to write device drivers for pc/linux etc. But the harder part is the cpu that can read the sd-card and copy it to the cartridge ram.

For me these ideas would be perfect. I could quickly make changes and quickly test results.

Now the other methods are good, but it just takes longer to get the changes to it and involve a more round about way.

Either way, programming it and testing it on an emulator would get perhaps 80% there, with some fixes to the emulator where "bugs" or "glitches" are not emulated correctly.

[TFM]

Ok. So replace your EPROM in some Cartridge by a Flash (you can take an old BIOS Flash of a PC for free), and flash it on your PC. That's it.

[arnoldemu]

Ok. So replace your EPROM in some Cartridge by a Flash (you can take an old BIOS Flash of a PC for free), and flash it on your PC. That's it.

True, but then I need a device connected to PC to flash it with.
e.g. Willem Programmer.

[TFM]

Yes, should be cheaper than building that for CPC.




Of course it would be a nice tool to have for the CPC. But I think its construction would be pretty complicated.

[TotO]

What is the flash IC model?

(if pin compatible, you may use the CTC-AY to program them from the CPC)

[andycadley]

I have an EPROM programmer and a few suitable EPROMs, so it would be better than nothing. But to get it out to the masses, you really need something a bit easier.

[mr_lou]

I have an EPROM programmer and a few suitable EPROMs, so it would be better than nothing. But to get it out to the masses, you really need something a bit easier.

I'll repeat my suggestion: "Mini cartridges".

We invent "Mini Cartridges" : A small cartridge containing only the EPROM chip. This mini cartridge can then be plugged into a bigger cartridge (containing the ACID chip what all other necessary stuff I know nothing about), and this bigger cartridge goes into the CPC.

It's like this already (almost) with Bryce's 4-way cartridge. It lets you replace the EPROM. All a "mini cartridge" would do is to make this exchange slightly easier for the average user.

[fano]

I'll repeat my suggestion: "Mini cartridges".

We invent "Mini Cartridges" : A small cartridge containing only the EPROM chip. This mini cartridge can then be plugged into a bigger cartridge (containing the ACID chip what all other necessary stuff I know nothing about), and this bigger cartridge goes into the CPC.

It's like this already (almost) with Bryce's 4-way cartridge. It lets you replace the EPROM. All a "mini cartridge" would do is to make this exchange slightly easier for the average user.

Already exists, it is the ManInTheMiddle by bryce : MITM - CPCWiki
Just have to add some decent plasturgy to this and we could have a 'decent' product...

[mr_lou]

Already exists, it is the ManInTheMiddle by bryce : MITM - CPCWiki
Just have to add some decent plasturgy to this and we could have a 'decent' product...

I didn't know about that. But yes, that's a solution. Not too elegant in its current state, but as you said, could be polished and then it would work.

But how does the user then disable the EPROM on the cartridge? Is that done automatically or does it require some user interaction?

[arnoldemu]

I didn't know about that. But yes, that's a solution. Not too elegant in its current state, but as you said, could be polished and then it would work.

But how does the user then disable the EPROM on the cartridge? Is that done automatically or does it require some user interaction?

it is automatic.

This solution is the one you describe. It does however need a good case to make it easy to insert/remove it. It also requires an edge connector which can be hard to find, or expensive to source (for connection of the original cartridge). Sources have been discussed for the edge connector. The solution works.

I think writing programs for the plus is easier compared to the cpc. Why?

The hardware sprites avoid the need for this on the cpc:
- clipping sprites
- displaying the sprites
- erasing the sprites

All of this is done by hardware.

If I had time to make some more example programs, concentrating on the plus, what would people like to see?

Please tell me and I will show how it can be done and that may encourage more people to code for plus.

[dcdrac]

I would love to see the Plus put through its paces something that pushes it all the way

[dcdrac]

An Elite style game or maybe a rehash of Dark side something like, Imagine Star glider or Carrier command as a Plus game
Fued in 3d?

Maybe Doom

[arnoldemu]

I would love to see the Plus put through its paces something that pushes it all the way

me too, but then I would love to see anything new that uses the plus hardware.