RAM 320XL

[atarian63]

I'll take when when you are ready!

[dmlloyd]

I would have liked to have seen an option (just an option mind you) for XLs to be modded with /HALT on one of the couple unused pins to support XE-compatibility. To me a RAM upgrade that isn't XE-compatible is just a non-starter.

 

Other than that, great project!

[Cliff Friedel]

Excuse me for being ignorant on this, but what would the benefit of this be? Most software is designed to use 64k and any software that took advantage of the additional RAM would only be usable by the people who had the expansion. This is not to say that I don't think this is cool or worth it, I am just wondering what the uses would be.

 

Cliff

[Rybags]

Expansions bringing machines to >128K have been around since the 1980s, so there's plenty of software around to take advantage of it.

 

For some people, just being able to run a huge RAMDisk is justification.

 

Also, there's games and other software being homebrewed that won't run on anything under 256K.

[+wood_jl]

I would have liked to have seen an option (just an option mind you) for XLs to be modded with /HALT on one of the couple unused pins to support XE-compatibility. To me a RAM upgrade that isn't XE-compatible is just a non-starter.

 

Other than that, great project!

 

 

Holy cow! You mean this IS NOT XE compatible? I was thinking this would "turn" your 800XL into a 320XE! So it doesn't??

[atariksi]

Excuse me for being ignorant on this, but what would the benefit of this be? Most software is designed to use 64k and any software that took advantage of the additional RAM would only be usable by the people who had the expansion. This is not to say that I don't think this is cool or worth it, I am just wondering what the uses would be.

 

Cliff

 

Most of the carts only use 16K.

 

I guess one use of a RAM drive is if you were emulating a PC on an Atari and the game happens to be Pac-man, you can load it all into RAM (2MB+) and the emulate one instruction at a time until Pac-man runs at a decent speed rather than swap things back and forth from disk drive during VBI.

 

 

I would have liked to have seen an option (just an option mind you) for XLs to be modded with /HALT on one of the couple unused pins to support XE-compatibility. To me a RAM upgrade that isn't XE-compatible is just a non-starter.

 

Other than that, great project!

 

 

Holy cow!

...

 

I presume you know the reason for "Holy" in Holy cow.

[Havok69]

I presume you know the reason for "Holy" in Holy cow.

 

I presume you know that's an expression; normally used to express surprise. I can see why you could be offended, seeing your website name and who it's registered to, however surely you hear worse in Jersey...

[atariksi]

I presume you know the reason for "Holy" in Holy cow.

 

I presume you know that's an expression; normally used to express surprise. I can see why you could be offended, seeing your website name and who it's registered to, however surely you hear worse in Jersey...

 

No, not offended at all. On the contrary, I find it quite an interesting expression.

 

 

 

 

Another use for extra RAM could be running some sort of video animation by uploading it all into RAM first and then decompressing it into a double bufferred ANTIC DL setup assuming you can't get ANTIC to directly access more than 128K RAM.

[dmlloyd]

Another use for extra RAM could be running some sort of video animation by uploading it all into RAM first and then decompressing it into a double bufferred ANTIC DL setup assuming you can't get ANTIC to directly access more than 128K RAM.

 

I think the most important use though is... games games games!

[Cliff Friedel]

Expansions bringing machines to >128K have been around since the 1980s, so there's plenty of software around to take advantage of it.

 

For some people, just being able to run a huge RAMDisk is justification.

 

Also, there's games and other software being homebrewed that won't run on anything under 256K.

I thought about it more and the RAMDisk definitely makes sense. I also thought it would be interesting if people used it to make a GUI based OS for the XL. Not sure how the CPU would handle the multitasking, but having a large amount of RAM would definitely be useful.

[+rdemming]

Holy cow! You mean this IS NOT XE compatible? I was thinking this would "turn" your 800XL into a 320XE! So it doesn't??

 

Not fully but that does not mean you miss a lot.

 

The original XE expansion has the option for separate extended RAM access for the CPU and Antic. You can turn bank switching on for only the CPU, only the ANTIC or both.

So Antic can access the extended RAM bank while the CPU still accesses the regular RAM. Or the other way around, the CPU access the extended RAM bank while the ANTIC still accesses the regular RAM. Or they can both access the extended RAM bank. With this system you can thus display graphics from extended RAM while the CPU runs code that is in the same memory range but in regular RAM.

 

A RAM expansion on the PBI bus cannot implement this feature because the proper signals to implement this are missing from the PBI bus. So if you turn on bank switching it is both for the CPU and ANTIC.

 

Pre XE memory extensions and the popular RAMBO extension didn't implement separate ANTIC/CPU access. So this feature was very little used. In fact I can only think of one demo that needs separate ANTIC/CPU access but there could be a few more. Nearly all other programs that need expanded memory don't need separate CPU/ANTIC access.

 

Robert

[+wood_jl]

I presume you know the reason for "Holy" in Holy cow.

 

Uh, I have an idea, now that you have brought it up. But that is not what I was thinking about when I used the expression. I was thinking more along the lines of XE compatibility. I should have said "Holy sh*t!" instead. I presume you know the reason for "Holy" in "Holy sh*t?"

Edited June 4, 2010 by wood_jl

[+wood_jl]

Holy cow! You mean this IS NOT XE compatible? I was thinking this would "turn" your 800XL into a 320XE! So it doesn't??

 

Not fully but that does not mean you miss a lot.

 

The original XE expansion has the option for separate extended RAM access.....<snip!>

 

Aaaah, "Antic enhanced mode" I recall the pseudo-moniker for this. Thanks very much for your explanation! Much appreciated.

[dmlloyd]

The original XE expansion has the option for separate extended RAM access for the CPU and Antic. You can turn bank switching on for only the CPU, only the ANTIC or both.

So Antic can access the extended RAM bank while the CPU still accesses the regular RAM. Or the other way around, the CPU access the extended RAM bank while the ANTIC still accesses the regular RAM. Or they can both access the extended RAM bank. With this system you can thus display graphics from extended RAM while the CPU runs code that is in the same memory range but in regular RAM.

 

A RAM expansion on the PBI bus cannot implement this feature because the proper signals to implement this are missing from the PBI bus. So if you turn on bank switching it is both for the CPU and ANTIC.

 

All that's really missing is /HALT.

[atariksi]

I presume you know the reason for "Holy" in Holy cow.

 

Uh, I have an idea, now that you have brought it up. But that is not what I was thinking about when I used the expression. I was thinking more along the lines of XE compatibility. I should have said "Holy sh*t!" instead. I presume you know the reason for "Holy" in "Holy sh*t?"

 

For a cow even the stool is holy (they make incense out of it and keep out bugs naturally). So it depends on whose stool you are talking about.

[atariksi]

Expansions bringing machines to >128K have been around since the 1980s, so there's plenty of software around to take advantage of it.

 

For some people, just being able to run a huge RAMDisk is justification.

 

Also, there's games and other software being homebrewed that won't run on anything under 256K.

I thought about it more and the RAMDisk definitely makes sense. I also thought it would be interesting if people used it to make a GUI based OS for the XL. Not sure how the CPU would handle the multitasking, but having a large amount of RAM would definitely be useful.

 

I'm pretty sure if games wanted a GUI, they could squeeze it into the 64K. I think one of the Pinball games uses a GUI and it runs on a 64K machine.

[atariksi]

Another use for extra RAM could be running some sort of video animation by uploading it all into RAM first and then decompressing it into a double bufferred ANTIC DL setup assuming you can't get ANTIC to directly access more than 128K RAM.

 

I think the most important use though is... games games games!

 

How many games are there that really need >64K RAM machine? Last I heard even Bomb Jack (Jake?) uses its own memory in the cartridge rather than the machine's RAM.

[ctirad]

 

I meant having both there like you have ROM at $C000...$FFFF currently on XL/XEs and there's also RAM there as well. That way, you can put some applications permanently in ROM and have them bank-switched at $4000...$BFFF (like 32K Atari 5200 carts).

 

I see. It is somewhat doable, but it would require redesign of the whole thing, use bigger cpld, implement flash write (or use fairly expensive FRAM instead), write a helper application, etc. etc.

[Cliff Friedel]

Expansions bringing machines to >128K have been around since the 1980s, so there's plenty of software around to take advantage of it.

 

For some people, just being able to run a huge RAMDisk is justification.

 

Also, there's games and other software being homebrewed that won't run on anything under 256K.

I thought about it more and the RAMDisk definitely makes sense. I also thought it would be interesting if people used it to make a GUI based OS for the XL. Not sure how the CPU would handle the multitasking, but having a large amount of RAM would definitely be useful.

 

I'm pretty sure if games wanted a GUI, they could squeeze it into the 64K. I think one of the Pinball games uses a GUI and it runs on a 64K machine.

I meant it more as a complete GUI OS ala Windows or X. As for GUIs in games, there are a couple I have seen that have menus and the like, but never really a whole GUI. Would be interesting to see.

[atariksi]

 

I meant having both there like you have ROM at $C000...$FFFF currently on XL/XEs and there's also RAM there as well. That way, you can put some applications permanently in ROM and have them bank-switched at $4000...$BFFF (like 32K Atari 5200 carts).

 

I see. It is somewhat doable, but it would require redesign of the whole thing, use bigger cpld, implement flash write (or use fairly expensive FRAM instead), write a helper application, etc. etc.

 

Well, you can avoid most of that by just having a socket for a flash chip like the 29F040B:

 

http://obs.carnegiescience.edu/instrumentation/ccd/parts/AM29F040B.pdf

 

and use like a ROM (no write mode). User can program on his own using EPROM programmer or whatever else. And use like the BASIC enable/disable bit of PORTB to toggle between RAM/ROM mode.

[ctirad]

 

Well, you can avoid most of that by just having a socket for a flash chip like the 29F040B:

 

http://obs.carnegiescience.edu/instrumentation/ccd/parts/AM29F040B.pdf

 

and use like a ROM (no write mode). User can program on his own using EPROM programmer or whatever else.

 

That would be indeed possible, but quite useless for most users.

The much better idea is a standard cartridge like this: http://raster.infos.cz/atari/hw/ramcart/ramcart.htm

 

And use like the BASIC enable/disable bit of PORTB to toggle between RAM/ROM mode.

 

That is correct from a hardware point of view, but I'm not sure it could work that way without patching a dos or even OS.

[Syfo-Dyas]

@atariksi - Why do people say "holy cow" is that in relation to the sacredness of the Cow in the Hindu faith? I.E. the mother bearing milk aka spiritual sustenance?

[Rybags]

As nice as having a flashROM on such an expansion, it inflates the price and makes the whole thing bloatware.

[atariksi]

As nice as having a flashROM on such an expansion, it inflates the price and makes the whole thing bloatware.

 

Good point-- how much would it inflate the price to add some sort of flashROM socket? If it's just a few bucks, it's worth having shadowing features (double the storage).

 

I would think the ram-drive software could be used for the rom-drive as well since extended memory (RAM) isn't really supported by OS either so DOS patch or driver is needed regardless if it's RAM or ROM. Currently, in SpartaDOS, they usually run something like "RD D8:" to enable the RAM drive.

[atariksi]

 

Well, you can avoid most of that by just having a socket for a flash chip like the 29F040B:

 

http://obs.carnegiescience.edu/instrumentation/ccd/parts/AM29F040B.pdf

 

and use like a ROM (no write mode). User can program on his own using EPROM programmer or whatever else.

 

That would be indeed possible, but quite useless for most users.

The much better idea is a standard cartridge like this: http://raster.infos.cz/atari/hw/ramcart/ramcart.htm

 

And use like the BASIC enable/disable bit of PORTB to toggle between RAM/ROM mode.

 

That is correct from a hardware point of view, but I'm not sure it could work that way without patching a dos or even OS.

 

Usability is in the hands of the beholder. If it's an easily implementable feature, why not go for it.

 

I don't think you need to patch OS nor DOS. The software can take advantage of it without any patches. And for compatibility, just replicate BASIC throughout the ROM and ROM bank combinations of PORTB should give the same result as if you were enabling/disabling BASIC.