Question About The Ram Configuration

[cb88]

Up to 8 Chip Select Pins With 128M-Byte Address Space per Chip Select Pin

does that mean that up to 1gb ram could theoretically be addressed on the archetecture? but in 8 addresses paces?

or am i misinterpreting that? and what exactly is a chip select pin?

I know it will come with 128mb same as teh n800 and non upgradable... i was just wondering

one more question... how is the dsp clocked? how will overclocking the cpu affect it?

 

[icurafu]

yes, 1 gig max.

but with the current tech, only 128MB. Will need to wait until the 256MB becomes less than crazy expensive.

 

[Squidge]

A chip select pin is a pin that selects a certain chip

You can use the same address lines to multiple chips, but unless the select line is driven to the chip, the chip will ignore all commands.

 

[anexanhume]

So, it depends on how the architecture drives the address lines versus chip select lines. If I had to guess, chip select lines are driven differently than address lines, which means 128M is the max size chip you can throw in there. However, there's nothing stopping you from including 2 (or more) 128MB modules. The problem is, that won't fit on the mobo without a major redesign. So, it sounds like 128M was chosen because it couldn't be any higher

You really should only need more than 128M if you're wanting to run multiple apps at once, which really isn't a UMPC's bread and butter.

 

[MWeston]

No, no, you guys have it all wrong.

There are eight chip selects, but only two can be used for SDRAM control. Those are the only ones you would really want to use for memory. Adding 128MB of SRAM on a chip select would be super expensive, take up a huge amount of board space and suck back the power like Pepsi cola.

So basically we have two chip selects for practical memory addition. Each chip select can decode up to 512MB of memory (remember addressing is not linear but based on row/column decoding).

This means that OMAP3 can handle up to 1024MB of DDR-333 memory which is fantastic for an embedded device like this, but stackable memory at that capacity isn't available yet and I don't even know when or if it will. Of course, we can buy regular DDR memory that could go on the PCB and add up to 1024MB, but the Pandora PCB has no room for it and still have over 50 buttons plus a bunch of connectors all over the place and still be close to DS-sized. The solution would be to add another PCB with the high speed stuff and stack it on the board, but that would cut the battery size in half and that goes against what we want for this system.

 

[cb88]

interesting and what of the DSP clock... i know there was some issue with the n800 where they dsp had to be underclocked for the cpu to run at it's rated speed.... I doubt that applies here though

 

[anexanhume]

No, no, you guys have it all wrong.

There are eight chip selects, but only two can be used for SDRAM control. Those are the only ones you would really want to use for memory. Adding 128MB of SRAM on a chip select would be super expensive, take up a huge amount of board space and suck back the power like Pepsi cola.

So basically we have two chip selects for practical memory addition. Each chip select can decode up to 512MB of memory (remember addressing is not linear but based on row/column decoding).

This means that OMAP3 can handle up to 1024MB of DDR-333 memory which is fantastic for an embedded device like this, but stackable memory at that capacity isn't available yet and I don't even know when or if it will. Of course, we can buy regular DDR memory that could go on the PCB and add up to 1024MB, but the Pandora PCB has no room for it and still have over 50 buttons plus a bunch of connectors all over the place and still be close to DS-sized. The solution would be to add another PCB with the high speed stuff and stack it on the board, but that would cut the battery size in half and that goes against what we want for this system.

Good, I'll take a super pandora 512 MB model then. k thx bai

Actually, I think 128mb is plenty. If you guys do decide to make a pandora 2 based on a omap 4xxx (or an nvidia based Cortex A9 SoC if they are making one ) or something higher, then I would expect 512MB, but that's years away

All we need know is mobile SoCs that can use XDR memory :lol: h34r: B)

 

[icurafu]

Just out of curiosity.

http://www.micron.com/products/partdetail?...T46H64M32L2CG-6

How much would this add to the cost of the unit? DDR333 is the maximum right?

 

[MWeston]

It will be at least double the cost of the 1gig part for sure, hopefully only double.

I've thought about the idea of a "special edition" Pandora with 256MB of RAM that would be closer to $399 in price since the volumes would be less and split the main production line.

I don't know how many people would buy it and I also don't know how good of an idea it is to split the community with software that starts popping up with "you need xxxMB of RAM to run my program!".

interesting and what of the DSP clock... i know there was some issue with the n800 where they dsp had to be underclocked for the cpu to run at it's rated speed.... I doubt that applies here though

My understanding is that there are separate PLLs to set the clock rates of the ARM core and DSP core in OMAP3, but since the SGX core is derived from a division of the ARM core (or just a fixed 96MHz clock), the same limitations could be imposed here as well.

It seems reasonable to assume that 600MHz on the ARM core allows for 430MHz on the DSP core since the datasheet shows these numbers. Overclocking the ARM core could change the DSP clock to lower dividers until you reach certain speeds, but I haven't really looked at it close enough yet. The datasheet is available for you to look at if you need a definitive answer right away.

 

[icurafu]

I'm not sure that a 256MB version would be a good idea for the reasons you mentioned.

I imagine the biggest use would be for the UMPC fantatics who want instant message while browsing in a desktop environment.

Or, to load a game that would work on a minimal 128MB Pandora while having a phat desktop installed.

There would also be a few games that could have a hi-res texture options or could have a few games make better use of the extra cache.

I don't think the means will meet the ends for most people and probably not even worth the production run, but intersting to know the comercials.

 

[fusion_power]

Many Consoles have less than 128MB RAM so I think the 128MB of the Pandora are MORE than enough. Not enough to waste ressources of course so the 128MB are a good way to force the Coders to optimize their programms Limited Ressources are always a good way to make clean code and clean programms.

The opposite we can see onto the PC: Gigs of Ram, big Hardware, fast Graphic Cards...and Games still stuttering. :lol: I've never liked the way, how modern PC Applications eat to much ressources. This should never happen onto the Pandora!

So, please never release a Pandora with more than 128MB RAM.

 

[dblank]

Many Consoles have less than 128MB RAM so I think the 128MB of the Pandora are MORE than enough.

Many consoles don't even come with a keyboard, screen, wifi, bluetooth, etc.
I'm glad the Pandora isn't trying to be like other consoles.

128MB isn't alot if you're planning on using it for more than just a gaming console.
It's not too difficult to use up 128MB when running a modern web browser, multitasking, etc.

Remember kids, it's not just for games!

 

[TaG]

If there were a 128MB and a $399 model with extra RAM, I would prefer the extra RAM model. But I really would not want there to be two models, and the price has been set at the lower level because of the community's views. So I will gladly settle for 128MB. Two models and we are into splitting the community and potentially allowing people to create less efficient code.

I'm with fusion_power. Please never release a Pandora with more than 128MB RAM.

 

[trooper]

I concur, Please don`t release different versions of the Pandora, A split in the community could be hurtful to such a niche product such as this. Especially talk about such hardware changes so early in the Pandora's life (ie, not released yet). It could upset quite a few potential customers in to thinking they are buying into an inferior product, If they were to opt for the 128MB model, Rather than the 256MB model that could be round the corner that they probably could not afford.

Maybe later in the pandora`s life an upgraded or tweaked version could be released, But please, Not yet, It` too early.

Just my 2p.

Trooper

 

[Kings]

As long as Wesnoth runs with only 128MB I'll be happy. If saurbraten(cube2) runs with 128MB then I doubt I'll graduate from college.

 

[fusion_power]

It's not too difficult to use up 128MB when running a modern web browser, multitasking, etc.

Remember kids, it's not just for games!

Do people really need heavy Multitasking onto such a Device? I don't even stress Multitasking onto my PC very much. Because I'm not a Woman I only can do ONE thing at the time.
When I should use a Webbrowser onto the Pandora, I think there will not run a Game or a Video into the background, (but maybe a W-Lan scanner ). I hope 128MB are more than enough for a good browser, mobile Firefox, Opera or whatever. We will never see Photoshop onto the Pandora (but I would like it ) so the 128MB is a very good number.

 

[TaG]

When I should use a Webbrowser onto the Pandora, I think there will not run a Game or a Video into the background, (but maybe a W-Lan scanner ).
MP3 player, IM, W-Lan scanner and some sort of to-do list or other business-like app so that it looks like I'm using Pandora as a PDA when my boss walks in.

Anything else?

I really have no idea how much RAM these 'simple' apps would use. I know it will depend on the specific apps, and I'm assuming lightweight and optimised apps, but does anybody have any ballpark figures that could give us an idea of what is realistic?

 

[dblank]

I hope 128MB are more than enough for a good browser, mobile Firefox, Opera or whatever. We will never see Photoshop onto the Pandora (but I would like it ) so the 128MB is a very good number.

I've run dozens of browsers on my N800, big fat full-featured browsers, tiny, minimal browsers, and everything in between. In my opinion it's really not enough, if it were, I probably wouldn't be running Dillo 90% of the time (no CSS, javascript, Flash, etc), and compressing and stripping images via a proxy. I'd be thrilled to browse the web just as I do on my laptop, but that's just not gonna happen with 128MB.

It's unlikely we'll see Photoshop, yeah, but there's plenty of other things that would benefit from the extra memory.

I'm sure it's "enough" for most people who will be buying a Pandora, and I understand the reasons for not including more.

An expansion port or something for RAM upgrades would be neat, but it's probably too late for that

 

[cb88]

seems like people don't remember when word ran in 16mb ram.... 128 IS plenty as far as that goes modern desktop linux (when configured properly... icewm and few deamons) can run in less than 64mb ram deli linux reccomends 32mb ! and it has a semi modern browser... If you throw KDE Gnome and all in there sure 128 is not enough... but if you look how good the alternatives are who cares I really don't see what the big deal is about desktop environments... all they do is suck ram

@dblank have you tried any recent builds of firefox 3? they are supposed to be 6 times faster at things like javascript and have a smaller mem footprint (still pretty huge though...)

...just because i have a one track mind doesn't mean that i can't multitask... LOL besides i often need a browser open and a media app and a console... then im set oh and in im program but then my productivity goes WAy down.....

 

[dblank]

seems like people don't remember when word ran in 16mb ram.... 128 IS plenty as far as that goes modern desktop linux (when configured properly... icewm and few deamons) can run in less than 64mb ram deli linux reccomends 32mb ! and it has a semi modern browser... If you throw KDE Gnome and all in there sure 128 is not enough... but if you look how good the alternatives are who cares I really don't see what the big deal is about desktop environments... all they do is suck ram

@dblank have you tried any recent builds of firefox 3? they are supposed to be 6 times faster at things like javascript and have a smaller mem footprint (still pretty huge though...)

Why would anyone want to run Word? Plain old ASCII text editors use next to zero memory, who needs word processing?

I don't see what Word running in 16MB of RAM 10+ years ago has to do with today, you can still run that old version of Word if you want. Maybe you don't want or need any of the new features, but others do.

My (properly configured) modern Linux desktop has 512MB of RAM, and Firefox 3 alone is currently using 200 of it.
I've used recent builds, yeah, and recent builds of WebKit and every WebKit based browser I could get to compile. They all end up gobbling RAM at some point; the modern web is bloated, and that's not gonna change anytime soon.

I can (and have) run Linux off a floppy disk, so what?

I don't see what the big deal is about color television, black and white is just fine for me, and it should be for everyone else.