Is it possible to build a megaflash with included 512kb Ram Exp and Lower ROM

[Bryce]

All my schematics and even the layouts are open source. Anyone who wants to use them is free to do so.

Bryce.

[Gryzor]

Yup, I didn't understand the comment. Bryce is kind enough to do everything pretty much open-sourced, and I don't recall him ever telling someone not to do something...

[TFM]

All my schematics and even the layouts are open source. Anyone who wants to use them is free to do so.

Bryce.

Yes, right, and that's appreciated. I've taken a look at it form a more general POV. It depends if someone tells "I think it's best to handle it this and this way" or if somebody tells "this and this has to be handled that way". The latter one makes things general.
As told, everyone can do what he wants, but other ideas should also be considered. Because ideas are NOT excluding each other. That's where I'm driving at    And now Happy Thanksgiving

[TFM]

Now since the SF2 is being sold again this thread becomes a bit obsolete.
However it may give rise to another idea: A card which contains usefull expansions, which are not part of the SF2.
What could that possibly be?
- LowerROM
- RS232 / RS442 network
- Ethernet
- USB Port (for storage devices, Flashdrive f.e.)
- Interrupt generator
- A/D converter
- Coprocessor (math... f.e.)
and what else do we need?

[Bryce]

Now since the SF2 is being sold again this thread becomes a bit obsolete.

How do you work that one out? The SF2 has 512K RAM, but it doesn't have Flash or LowerROM.

I still don't intend building it or the list of other devices you've mentioned (ok, maybe one or two of them are on my list), but I still wouldn't make it as one big device.

Bryce.

[TFM]

How do you work that one out? The SF2 has 512K RAM, but it doesn't have Flash or LowerROM.

Please read my entire post.

I still don't intend building it or the list of other devices you've mentioned (ok, maybe one or two of them are on my list), but I still wouldn't make it as one big device.
Bryce.

You must not build it. Anybody can do. This is an open thread. And it's open for discussion.

[Bryce]

Please read my entire post.

I did. Still can't spot what I might have missed.

Bryce.

[TFM]

Then please Read again..... I mentioned the LowerROM. And if an expanson uses Flash or S-RAM is secondary.
The point here is different. When I read the first post then I have the impression that Pentagon did want to invent a kind of SF2-replacement, since the SF2 was sold out in these days. Now the SF2 is available again, so we don't need a replacement.

[Bryce]

And if an expanson uses Flash or S-RAM is secondary.

That's where I would disagree. The SF2 might offer virtual ROMs, but the difference between battery backed SRAM and Flash is huge. Not only for the size of the device, but also for it's usability, the life of the device and even the functions possible. So I don't see them as the same at all.

Bryce.

[TFM]

Well, a Flash can keep data longer as an S-RAM with battery. But and S-RAM can be written more often than Flash.
One problem could be: How hard is it to change the battery? And the other hand: How long doese data resite in Flash?

There is something else: The Pseude-ROM of the SF2 can be read and written without the need of using a physical switch. You can abuse it as additional 512 KB RAM. And this can be done with full writing speed. This was a ROM disc could be quite easy to handle.

[Bryce]

The type of Flash I used on the MegaFlash can be written to up to at least 10,000 times per slot. That's equivalent to changing at least 2 ROM slots per day for approx. 14 years. Highly unlikely that even a power user would achieve that. And even if he did, he just pulls it out of the socket and replaces it for less than €10, without needing to know which end of a soldering iron gets hot.
The data retention is rated at 10 years. But in reality they manage a lot more. Should also be long enough for most CPC users.

SRAM certainly has advantages, but I think the need for a battery outways these. The MegaFlash would be possible without a switch. I think I even built one during the development stage. I chose to have a switch.
Battery swapping isn't a really hard soldering job, but the footprint of the components have changed over the years, so the old version is difficult to find. There's also the risk that it leaks and destroys the board completely. Ask any Amiga Fan.

Bryce.

[TFM]

Well, the Winbond is already hard to get, but sure it will not be used up in a regular way. However if you use it as ROM disc, then that number of cycles may be used up quit.
An accumulator in an socket would also not be a bad idea.

[Bryce]

The Winbond Flash I used is an EOL part, but they made millions of them. It's still very easy to find (almost every supplier I use stocks it) and should be for the next few years. There are also a few alternative manufacturers of this part.

Bryce.

[TotO]

A Flash IC can't be used as RAM replacement.
If a program write it 50 times per second for processing data to display, it's not 14 years of life but only 3mn.

But, when you got huge ROM memory, you don't need so much RAM.

The lower ROM replacement is a great feature.
CTC and SIO too.

Others are useless in my point of view, as serial connexion can be handled through a BT module to share network data with PC and phones.

[Bryce]

A Flash IC can't be used as RAM replacement.

That's what I meant, when I said that SRAM has advantages over Flash.

Of course the MegaFlash was never meant to be used as RAM. It's a ROMBoard

Bryce.

[Gryzor]

I am now confused as to the point of this thread.

[TotO]

I am now confused as to the point of this thread.

The answer was done.
Yes, it's possible to build a Megaflash including the Lower ROM, but charts give 60% of users interested about an external module only.
Free to others to do it.

[Gryzor]

Quote from: Gryzor on Today at 12:54:22I am now confused as to the point of this thread.The answer was done. 

Yup, hence the "now" in my quote

[fano]

and what else do we need?

A blitter ! ok i stop dreaming 

[Gryzor]

Wot, no 4MB?

[TotO]

Wot, no 4MB?

The eternal question... May be, doing 128K stuff before?
4MB need extra decoding and will not be used and no common existing storage device allow to fill it with data.

[beaker]

Well if I super glue the boards together I am already there with the 512k, Megaflash and LowerROM

[attach=2]

Wot, no 4MB?

[Gryzor]

Quote from: Gryzor on Today at 14:17:25Wot, no 4MB?The eternal question... May be, doing 128K stuff before?
4MB need extra decoding and will not be used and no common existing storage device allow to fill it with data.

Was only kidding

[TFM]

The eternal question... May be, doing 128K stuff before?
4MB need extra decoding and will not be used and no common existing storage device allow to fill it with data.

Well, IMHO, a 704 KB disc (Vortex format for example) can hold compressed data. Uncompressed this can easily be 4 MB (especially when dealing with GFX). And then there is the new batch of SF2's and the CPCSD.