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MegaFlash Progress

Started by Bryce, 20:25, 03 March 11

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qbert

A question : would it give the possibility to switch off each bank individually or 16 bank at a time ? If not, why ?
An usable ROM configuration most probably have to change the ROM distribution from boot to boot or it will give much work to software reset/reload the various banks from disk between two differents usages  :-[ . That why a simple switch system would be so useful.
But I'm still interested for sure , whatever happen.

Bryce

You can switch off ROM 0 and ROM 7 individually with hardware (jumpers) and you can switch off any other ROM individually with the ROMManager and other ROM Management software but that's it. Adding a switch for every one of the 32 ROMs would mean adding quite a bit of additional components which would push up the size and the price, which goes against my rules of "Keep it small, keep it cheap".

Bryce.

Gryzor

Now, let's see how long for a floppy emulator/Megaflash combo ;)

Bryce

That's up to the software people, not my department :)

Bryce.

qbert

Another question about the banks, but not specifically Megaflash-related this time (RAMCARD and other Rom-Ram Boxes are concerned too)
Counsidering Bank 0 and 1 are covered by the card, is that possible to override the motherboard's BASIC and Firmware banks ? i.e having BASIC 1.1 on a 464 for example...

OCT

Quote from: Bryce on 21:15, 16 July 11
You can switch off ROM 0 and ROM 7 individually with hardware (jumpers)
Is there a way they can override/ROMDIS both of the CPC's internal ones? I seem to recall only one of the ROMs was wired to allow for that - so does it require a small hardware modification for the other?

Another interesting option would be the ability to have various "flavors" of 0 (e.g. 464/6128/6128+) and 7 (AMSDOS/PARADOS/&friends) selectable for the many pieces of software that won't work on the more advanced ones - I have switches to toggle among the first two of each (in piggy-backed physical EPROMs) on my old-generation 6128 of course.

Bryce

@qbert: Yes, you can overwrite ROM 0 (Basic) on any CPC, but you can not simply replace Basic 1.0 with Basic 1.1 without having replaced the lower ROM (Firmware), the reason for this is that the Firmware Version has to match the Basic Version. You can create patched/edited Basic ROMs and no changes need to be made inside the CPC. The MegaFlash can't overwrite the Firmware, so this would have to be done inside the CPC or with an additional expansion card.

@OCT: Correct, on Classic CPCs you can only overwrite ROM 0, but ROM7 can only be replaced by the MegaFlash ROM 7 if the internal one has been disabled manually, ROMDIS on Classic CPCs cannot disable ROM 7. On plus machines, you can overwrite ROMs 0 and 7 with the MegaFlash without modifying the CPC. And obviously all 464 don't have a ROM 7, so you can use that position on a 464, unless of course you have a DDI-1 attached, in which case you would have to disable the ROM in that. The most useful function here is with a 6128+, where switching JP2 allows you to switch between AMSDOS and an alternative (ParaDOS or whatever) on the MegaFlash.

Bryce.

OCT

#107
Quote from: Bryce on 12:47, 17 July 11On plus machines, you can overwrite ROMs 0 and 7 with the MegaFlash without modifying the CPC. [...] The most useful function here is with a 6128+, where switching JP2 allows you to switch between AMSDOS and an alternative (ParaDOS or whatever) on the MegaFlash.
If I understand this correctly, the Plus might be able to start up from nothing but the MegaFlash even without a cartridge?
And the MegaFlash (just like a modified cartridge formerly did) might present to the Plus a "classic" 464 or 6128 ROM (and possibly AMSDOS if that is different to the old one as well - IIRC only the latter supported Logo, but no system disks came with my very recent&first-ever-acquired Plus anyway; sorry for being two decades late to the show ;)), eliminating some source of incompatibility?
However, it would get yet more versatile if it had one more switch to select which of its ROMs it presents as to the CPC(+) as 0 or 7, respectively?

Bryce

No, the Plus can't start with only a MegaFlash because it needs an ACID to start, which the MegaFlash doesn't have.

And no, the MegaFlash can't offer several versions of ROM 0 or 7, it just has one ROM 0 and one ROM 7 which can over-write the internal/cartridge ROM.

Sorry to rain on your party :( but the ROM numbers are hard-wired on the MegaFlash, you can't just pick one and say: "This one is ROM 0/7"

Bryce.

OCT

Quote from: Bryce on 21:44, 17 July 11
No, the Plus can't start with only a MegaFlash because it needs an ACID to start, which the MegaFlash doesn't have.
OIC, thought the ACID was only required for its advanced features.

Quotethe MegaFlash can't offer several versions of ROM 0 or 7, it just has one ROM 0 and one ROM 7 which can over-write the internal/cartridge ROM.

Sorry to rain on your party :( but the ROM numbers are hard-wired on the MegaFlash, you can't just pick one and say: "This one is ROM 0/7"
My thinking was that it might be possible to toggle one address bit to turn another ROM into the required one, as it used to be done with quad-capacity EPROMs longer than the actual sockets.
If it is not, there will still be the ROM manager to replace them as needed, but switching them in place might have been even more useful.

Bryce

Strange, I also always thought that the ACID only enabled enhanced features and it's also documented that way (or at least confusingly) in many places which would lead you to believe that, but I have been corrected by people who know better and I have also confirmed this with my own tests. The ACID is always required.

Ah, I see what you mean (regarding toggling bits). Yes that might be possible, but I never considered that feature and it might get confusing when writing the ROMs, but technically possible.

Bryce.



Executioner

I thought the ACID was only used to encode the data from the cartridge so the Plus could read it, and was there to make it hard to copy cartridges. I don't think the ACID applies at all to external ROMs. Does the MegaFlash allow replacement of the Lower ROM (firmware). If a ROM box could do that on a Plus, you should be able to boot straight into a custom ROM plugged into the expansion port and dump carts with no other hardware.

Bryce

No, the MegaFlash only replaces ROM 0 Basic and as far as I have been told, even replacing lower ROM wouldn't avoid needing an ACID. As far as I know (and here I'm just repeating what others have told me), the ACID functionality is hardwired into the ASIC and is always needed no matter what the CPC is trying to run.

Bryce.

arnoldemu

Quote from: Bryce on 07:59, 18 July 11
As far as I know (and here I'm just repeating what others have told me), the ACID functionality is hardwired into the ASIC and is always needed no matter what the CPC is trying to run.

Bryce.

My understanding is the same.

The ACID talks to the ASIC. If the conversion is not correct, the z80 is forced to read bad data and it will then crash.

To use advanced features, you send a special sequence *to the ASIC*, acid is not involved.

I think the idea is that a cartridge *MUST* be inserted for the plus to run, but only because the cartridge also contains the acid.
The ROM data is not encrypted as we know.

If you inserted a tiny board with just an ASIC on it into the cartridge slot, the plus will boot. It will then read "floating bus" unless some roms assert themselves.  So then the roms need to be provided externally (rom board to provide 0-15, other to provide OS) ;)
My games. My Games
My website with coding examples: Unofficial Amstrad WWW Resource

Bryce

Hi all,
     I need to start finding out how many people want a MegaFlash so that I can tell the PCB manufacturer what I need built. Can you please send me a PM if you are interested in having one (or more). It looks like the price will be €75. I can supply the connection cable for Centronics CPC's for €7 extra and I have managed to source 10 50way edge-connectors, but they were expensive, so the edge connector cable will cost €10 and the first ten people to order them get them. Postage will be €5 for Europe.

Thanks,
Bryce.

TFM

#115
And with the Hardware the new Software comes along.

Yesterday I uploaded the new version of the FlashROManager. Now it has the "Check Flash" option. This is a fair compromise between time and depth. So it will check all 512 KB Flash for errors. It will need six minutes and it will check with values &00, &55, &AA and &FF.

I hope you like it. (At the moment a detailed error anaylsis is missing, but if it finds an error, the border will flash in (turn to) yellow-orange. Else (no Flash error) the border becomes blue (black) again.

Quote from: qbert on 21:06, 16 July 11
A question : would it give the possibility to switch off each bank individually or 16 bank at a time ? If not, why ?

There is no need for a hardware solution, we planned to create the MegaFlash as cheap as possible.

So if you want to switch on or off some ROMs you can just use the Unpark / Park function of the FlashROManager Software. And you can get it for FutureOS and for BASIC. (Also a ROM is planned).

Quote from: qbert on 21:06, 16 July 11
An usable ROM configuration most probably have to change the ROM distribution from boot to boot or it will give much work to software reset/reload the various banks from disk between two differents usages  :-[ . That why a simple switch system would be so useful.
But I'm still interested for sure , whatever happen.

The software provides an option to load all 32 ROMs at once. But you need a 0.7 MB formatted disc. I suggest Vortex Format (tested).

Quote from: qbert on 08:13, 17 July 11
Another question about the banks, but not specifically Megaflash-related this time (RAMCARD and other Rom-Ram Boxes are concerned too)
Counsidering Bank 0 and 1 are covered by the card, is that possible to override the motherboard's BASIC and Firmware banks ? i.e having BASIC 1.1 on a 464 for example...

Well, it would crash the CPC if you use another BASIC. Because if you replace the BASIC version, then you MUST replace the Lower ROM in addition. Only a replacement of both will work.

Quote from: OCT on 11:27, 17 July 11
Another interesting option would be the ability to have various "flavors" of 0 (e.g. 464/6128/6128+) and 7 (AMSDOS/PARADOS/&friends) selectable for the many pieces of software that won't work on the more advanced ones - I have switches to toggle among the first two of each (in piggy-backed physical EPROMs) on my old-generation 6128 of course.

You can install different DOS (Amsdos, VDOS, XD-DOS, RDOS and maybe ParaDOS) in different ROM slots. The DOS with the _smallest_ ROM number will always be active. The other DOSes should be parked to save RAM.

If you only have a single DOS UNparked (normal) and all others are parked, then you will work with that DOS without problems, but...

You will get problems with software that directly uses ROM7.

Quote from: Bryce on 22:05, 17 July 11
Strange, I also always thought that the ACID only enabled enhanced features and it's also documented that way (or at least confusingly) in many places which would lead you to believe that, but I have been corrected by people who know better and I have also confirmed this with my own tests. The ACID is always required.

Well, the ASIC (the big chip on the motherboard) provides the additional features of the CPC Plus. And the ACID (small chip on every cartridge) is only for copy-protection means. Both chips are needed to run a CPC Plus (disregarding Octoates ACID replacement).

Quote from: arnoldemu on 10:13, 18 July 11
If you inserted a tiny board with just an ASIC on it into the cartridge slot, the plus will boot. It will then read "floating bus" unless some roms assert themselves. So then the roms need to be provided externally (rom board to provide 0-15, other to provide OS) ;)

Well, that is coming close, but it's not enough. There must be a lower ROM in addition, the Z80 will start to work at address &0000 (after power-on / reset) and external ROM boards don't provide a lower ROM (disregarding the MF2).

I haven't forgotten the Flash-disc idea. However this is not a project that must be startet now, since I'm currently in developping half a dozend of things at the same time. So hopefully later on ;-)
Also I guess it's an advantage to listen to people, what do they want. Just taking some time to think about it.
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

TFM

After a long weekend and a Monday full or work...


MegaFlash and ROManager Demo

Video showing CPC Plus from Bryce working with the brand new MegaFlashROM. Thank's to Bryce for the Video! Now it all works well :)
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

qbert


Gryzor

Love the Ding sound. Great job!!!!

One small suggestion: can you draw a window for the file list on the right? It doesn't look too good right now...

Bryce

The "Ding" sound is a very pleasant sound when you program the device once. But when you spend an entire evening testing the MegaFlash and you've heard that sound over 100 times, it does tend to get very irritating, but that's not a worry for the normal user.

Bryce.

Gryzor

Quote from: Bryce on 09:51, 19 July 11
The "Ding" sound is a very pleasant sound when you program the device once. But when you spend an entire evening testing the MegaFlash and you've heard that sound over 100 times, it does tend to get very irritating, but that's not a worry for the normal user.

Bryce.


No "Mute" button on your CPC? :p


redbox

Quote from: TFM/FS on 21:18, 18 July 11
Video showing CPC Plus from Bryce working with the brand new MegaFlashROM. Thank's to Bryce for the Video! Now it all works well :)


Great work Bryce and TFM, looks really good.


Btw Bryce, you need a copy of my patched cartridge - no annoying f1/f2 menu and you can still access Burnin' Rubber if you really want to by RSX  :)

Bryce

Actually, I usually use a patched ROM on the MegaFlash which also skips the F1/F2 screen, but the MegaFlash was empty (other than Maxam) for the Demo.

Bryce.

redbox

Ah ok, will let you off just this once  ;)


Forgot to say that the picture on your monitor from the modulator looks really good too.

Bryce

Thanks, the picture is being produced using my S-Video Modulator being fed into a V2V S-Video to VGA converter. The monitor is a standard 19" 4:3 LCD VGA Monitor.

Bryce.

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