Upgrading a CPC 464 in 2022

Uityyy · 08:52, 18 October 22

I just purchased a bare CPC 464 and have been digesting the CPCWiki buyer's guide and the requirements for eventually running SymbOS and FutureOS. Can anyone give me pointers on which of the known RAM and storage expansions are easy to get a hold of in 2022 and anything I should know about getting multiple upgrades to play nicely with each other?

Cwiiis · 11:36, 18 October 22

Any RAM expansion will do on the 464, and to run symbOS you'll also need ROM expansion and optionally mouse, wifi, mass storage and RTC... The M4 wifi add-on will get you everything except RAM, but it's a long wait right now due to the components shortage - check the thread on this forum. The RSF3 will get you everything and more, but I don't know how available it is/will be right now - check out tmtlogic.com for info.

If you don't so much care for mass storage/wifi/mouse (and more...), the X-MEM is a really good option: http://www.centpourcent.net/ - this gets you just RAM and ROM expansion and costs significantly less than the M4 or RSF3.

If you decide that actually, running symbOS and FutureOS isn't that important and you just want to play games, the usifac2 is a great, low-cost option for the 464... But you might want to wait until the ulifac is available, which will combine that with ROM and RAM expansion.

GUNHED · 14:39, 18 October 22

Quote from: Uityyy on 08:52, 18 October 22I just purchased a bare CPC 464 and have been digesting the CPCWiki buyer's guide and the requirements for eventually running SymbOS and FutureOS. Can anyone give me pointers on which of the known RAM and storage expansions are easy to get a hold of in 2022 and anything I should know about getting multiple upgrades to play nicely with each other?

Regarding the RAM expansion you need the one from @revaldinho , because it's the only one which allows the CPC464 the proper implementation of RAM mode &C3. This is mandatory for running original CP/M Plus and FutureOS.
Also I would like to suggest you an ROM expansion. There are many solutions.
It you like to have a ROM expansion with mass storage (SD card up to 32 GB) and Wifi then please get the M4 card from @Duke

Uityyy · 15:47, 18 October 22

Thanks so much for the feedback! I did see revaldinho's boards specifically recommended. Do the PCBs from Seeed studio come prepopulated, or is there a list of components that need to be added in some part of his git repository that I haven't looked at yet? And are any special tools needed for writing the firmware?

Would it be correct to say that none of the multi-function expansions out there have yet replicated his correct &C3 mode and thus I should avoid anything else with built-in expansion RAM such as the DDI-4 or RSF3 as a likely hardware conflict, or has, say, has the CPC SYMBiFACE 3 v2.1 from TMTLOGIC been updated to do the same as revaldinho's? (It advertises "CPC 464, Extern memory hack" and is new enough that it does not yet have a wiki page.)

And how does one use a ROM expansion if one does not have an EPROM burner?

Uityyy · 16:04, 18 October 22

Oh, and do these things that include their own storage such as the M4 and SYMBiFACE III preclude having a physical 3" drive plugged in at the same time?

TotO · 16:54, 18 October 22

Quote from: GUNHED on 14:39, 18 October 22Regarding the RAM expansion you need the one from @revaldinho, because it's the only one which allows the CPC464 the proper implementation of RAM mode &C3. This is mandatory for running original CP/M Plus and FutureOS.

The shadow RAM feature is not required by CP/M Plus. In fact, it is only required for Future OS.
The reason is you don't want to patch your software, so the user lost 64K RAM for the mouse pointer.

d_kef · 17:40, 18 October 22

Quote from: TotO on 16:54, 18 October 22
Quote from: GUNHED on 14:39, 18 October 22Regarding the RAM expansion you need the one from @revaldinho, because it's the only one which allows the CPC464 the proper implementation of RAM mode &C3. This is mandatory for running original CP/M Plus and FutureOS.
The shadow RAM feature is not required by CP/M Plus. In fact, it is only required for Future OS.
The reason is you don't want to patch your software, so the user lost 64K RAM for the mouse pointer.

As far as I know CP/M Plus does need C3 mode. If you have/know of a version that doesn't then I'd be grateful if you could send me the .EMS or point me to a download link.

d_kef

TotO · 17:49, 18 October 22

Quote from: d_kef on 17:40, 18 October 22As far as I know CP/M Plus does need C3 mode. If you have/know of a version that doesn't then I'd be grateful if you could send me the .EMS or point me to a download link.

Sure, it require the C3 mode, but not the shadow RAM feature. So, most RAM expansions since dk'tronics in 1986 support CP/M Plus.

GUNHED · 18:36, 18 October 22

Quote from: TotO on 16:54, 18 October 22
Quote from: GUNHED on 14:39, 18 October 22Regarding the RAM expansion you need the one from @revaldinho, because it's the only one which allows the CPC464 the proper implementation of RAM mode &C3. This is mandatory for running original CP/M Plus and FutureOS.
The shadow RAM feature is not required by CP/M Plus. In fact, it is only required for Future OS.
The reason is you don't want to patch your software, so the user lost 64K RAM for the mouse pointer.

We had this discussion before and it's bullcrap!
Not a bit of RAM is lost. Keep your propaganda to yourself - seriously!
FutureOS just uses a smart way to access the V-RAM from ROM.
And if CP/M Plus would run with a regular memory expansion on CPC464, why does it need to be patched then?
Please don't answer, this was a rhetorical question.

TotO · 19:24, 18 October 22

The 64K shadow RAM is only required to workaround the C3 mode when a ROM is paged (FutureOS ROM). So, 448K left.
Go to Github to see it by yourself: https://github.com/revaldinho/cpc_ram_expansion/wiki/Universal-Amstrad-CPC-RAM-Card

CP/M Plus works fine with the dk'tronics expansions (and others) because it run from the RAM.

Uityyy · 20:20, 18 October 22

Ok. So the impression I'm getting so far is that if I want a single hardware configuration compatible with
A. SymbOS
B. FutureOS
C. 3" floppies
D. transferring data to/from a PC

I must have attached to my CPC464:

A power cable
A video cable
A RAM expansion (for A and B)
with C3 shadow support (for B)
A ROM expansion (for B only; SymbOS's site indicates it is optional, contrary to what was said here)
Most likely a backplane to juggle all those expansions (A, B, C, D)
A Disk Drive Interface (A, C, and maybe D)
A ribbon cable (C)
A physical drive (C)
A drive emulator or some sort of serial link or some sort of internet link or some sort of way to read a 3" disk on a PC (D)
A joystick or mouse (A and B)

I fear I cannot use:

RSF3 (included RAM probably conflicts with #4)
DDI-4/DDI-5 (included RAM probably conflicts with #4)
ulifac (included RAM might conflict with #4 and maybe not compatible with #1 and #2)
X-MEM (does not provide #4)
M4 (included disk driver may conflict with #7?)
usifac2 (might conflict with #7? or be somehow incompatible with #1 and #2?)

If everything I fear is wrong is wrong, that leaves only revaldinho's RAM board usable out of everything mentioned on this thread, and I guess then your best options for flash storage are something like a Gotek connected as a second drive to an original DDI.

Please do chime in if you know ways in which these modern retro peripherals are less of an incompatible mess than I'm fearing.

eto · 22:03, 18 October 22

Is that whole C3 topic documented somewhere? I only find bits and pieces around it.

I guess C3 for 464 and 664 always requires the shadow RAM trick unless we do a hardware modification inside the computer, is that right?

Revaldinho mentions in his documentation that (besides Future OS) there are "modern games" that would also need C3 on a 464. Which games would that be? And why would they need C3?

Prodatron · 22:24, 18 October 22

#C3 is for some special ROM stuff only. That's the reason why most software don't need this and why most ram expansions, including popular classic ones, don't provide this and still work fine with nearly everything.

d_kef · 11:41, 19 October 22

Quote from: Prodatron on 22:24, 18 October 22#C3 is for some special ROM stuff only. That's the reason why most software don't need this and why most ram expansions, including popular classic ones, don't provide this and still work fine with nearly everything.

In fact according to AMSTRAD #C1, #C2 and #C3 RAM modes "are only useful to the implementation of CP/M Plus."

d_kef

TotO · 11:50, 19 October 22

Some games and demo are using #C1 (R-Type 128K), few are using #C2 (Orion Prime) and #C3 (Pac-Man emulator)

d_kef · 12:12, 19 October 22

True!!! But is it useful to them???

d_kef

GUNHED · 12:14, 19 October 22

Quote from: TotO on 19:24, 18 October 22The 64K shadow RAM is only required to workaround the C3 mode when a ROM is paged (FutureOS ROM). So, 448K left.
Go to Github to see it by yourself: https://github.com/revaldinho/cpc_ram_expansion/wiki/Universal-Amstrad-CPC-RAM-Card

Using FutureOS on a CPC6128 with X-MEM provides 640 KB RAM total and every bit can be used. On a 464 or 664 there are 576 KB of RAM free and every bit can be used.

Revaldhinos page does NOT state that RAM is lost for using RAM mode &C3.
There _IS_ no such thing as a shadow RAM.

But of course adding a regular 512 KB RAM expansion to a 6128 will only provide 576 KB (because one 64 KB bank is unused). That has nothing to do with RAM mode &C3. Only the X-MEM provides 640 KB in this case, but it's not fully 6128 banking compatible on 464/664.

GUNHED · 12:34, 19 October 22

Quote from: Uityyy on 20:20, 18 October 22If everything I fear is wrong is wrong, that leaves only revaldinho's RAM board usable out of everything mentioned on this thread...

Yes, the Revaldhino RAM expansion and I guess the SF3 (I heart it does the trick too, but you can ask the producer to be sure).

eto · 12:38, 19 October 22

Quote from: GUNHED on 12:14, 19 October 22Revaldhinos page does NOT state that RAM is lost for using RAM mode &C3.
There _IS_ no such thing as a shadow RAM.

Have you seen this section?

You cannot view this attachment.

If I am not mistaken C3 compatible mode on a 464 and 664 can only be achieved by cutting tracks OR implementing shadow RAM and sacrificing 64KB of the additional RAM for it.

GUNHED · 12:43, 19 October 22

No, it's not in the link provided by Tot0. Can you provide the direct link please?

However, this seems to be true for the 1 MB expansion.
I talked about the 512 KB expansion.

revaldinho · 12:57, 19 October 22

There is a full manual for my cards available on the GitHub site here: User Guide and Technical Manual

In short, there is a bank of DIP switches on the board which you can use to select different operating modes.

Like all other cards, the two Revaldinho boards support CPC6128 computers with either a full 512KB or 1MB of RAM depending on which card you have.

For the 464/664, running in DK'Tronics mode, you also get a full 512KB or 1MB of RAM.

For the 464/664 running FutureOS or any other software which insists on a 'perfect' C3 mode implementation, then you need to use the shadow RAM mode. This is the only time that you have to pay the penalty of giving up a bank of 64K, reducing expansion RAM capacity to 448KB or 960KB respectively.

So, for the OP who specifically wants to run FutureOS on a 464, this is a good choice of card. Indeed, it may still be the only card that supports this, and it has no disadvantage over any other card as far as running non-C3 mode software goes.

I think that you can still get these cards on cpcstore.co.uk.

I don't sell on eBay or anywhere else, but I'm always happy to build up small numbers of boards for CPCWiki users. So, if you decide that you want one and can't find one (cheaply) elsewhere, feel free to PM me.

eto · 13:11, 19 October 22

Quote from: GUNHED on 12:43, 19 October 22No, it's not in the link provided by Tot0. Can you provide the direct link please?

However, this seems to be true for the 1 MB expansion.
I talked about the 512 KB expansion.

It's true for both cards. You can find the documentation on the page that Toto provided, if you follow the links there.

1MB Card is limited to 960KB as documented here:
https://github.com/revaldinho/cpc_ram_expansion/blob/master/cpc_ram_expansion1mb/doc/Revaldinho%20Universal%201MByte%20RAM%20Card%20User%20Guide%20and%20Technical%20Documentation.pdf

512KB Card is limited to 448KB as documented here:
https://github.com/revaldinho/cpc_ram_expansion/blob/master/cpc_ram_expansion/releases/rc-6-fighter/CPCUniversal512KRamExpansionRC6FighterRelNotes.pdf

As a 464/664 cannot deal with A14/A15 for bank 0 like the 6128 does, a RAM extension has to shadow bank 0 to imitate the behaviour of the PAL - but it can only do this with its local RAM, not with the RAM inside the CPC. While in C3 mode, the CPU will not read from built-in RAM but from the shadowed RAM.

Quite clever idea I have to admit. And if you have a total of 512KB or 576KB will rarely matter.

GUNHED · 13:12, 19 October 22

Thanks for the information Revaldhino.

TotO · 13:43, 19 October 22

Quote from: GUNHED on 13:12, 19 October 22Thanks for the information Revaldhino.

And no "excuse" for insulting me and pretending otherwise?

GUNHED · 14:36, 19 October 22

Quote from: TotO on 13:43, 19 October 22
Quote from: GUNHED on 13:12, 19 October 22Thanks for the information Revaldhino.
And no "excuse" for insulting me and pretending otherwise?

And no "excuse" for always picking at me?

So, sorry for the misunderstanding then.

However no RAM is lost. There are DIP switches for configuration, it's not hardwired.

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Upgrading a CPC 464 in 2022