Can The Kernel Support 8 Memory Banks?

[niv]

current memory in my zaurus 5500 is 64 Mb -> two chips . each chip is 8M X 16 bit X 2 banks (correct?)

some places offer an upgrade to 128 - for ipaq users. these places also offer a 256 upgrade by soldering on chip on-top of the other. so the math for each chip will be :
8M X 16 bit X 8 banks

According to the strong ARM spec - it may have 8 banks vancant.

So - can we do it?

[bsaunder2002]

I investigated this with www.pocketpctechs.com.  We sent several emails back and forth.  It appears that the boot loader must initialize the memory.  Someone in Japan had hacked it to do this but I never found a released boot loader.

Since the stock boot loader works fine for booting alternative versions of the OS(OZ, pdaxrom, ...) nobody has taken the time to rewrite it.

Also the source for the original boot loader was not release by Sharp.

So pocketpctechs didn't want to upgrade my SL-5500, but said if I could get a bootloader working and enough customer's they'd look into it.

(ps - correct me if I'm wrong in any of the above)

So,
- is it possible? - Yes

- has it been done before - I think so, it was a Japanese site and I cant seem to find it anymore, though an upgrade to one of the clamshells is still present.

- be careful, some of the sites which have pictures of the SL-5500 internals are actually showing the SL-5000 (32 mb chips)

- has anyone seen a CF card that uses SRAM instead of flash?  This would make a nice swap file

- 128mb would be fine, yes we can work in 64mb but anything more would be better

- battery life? I'd hack the larger battery into the SL-5500 if needed, I'll probably need it for my GPRS modem anyway.

Bill

[niv]

thanks mate - any chance for a link?

I will try more googling tomorrow.

[eekee]

I investigated this with www.pocketpctechs.com.  We sent several emails back and forth.  It appears that the boot loader must initialize the memory.  Someone in Japan had hacked it to do this but I never found a released boot loader.

I'm no expert, but maybe the work being done by the LinuxBIOS folks could be of some use?

Before work gets started on that, though, I do have to ask the obvious question: Is is a Known Fact that the collie bios won't initialise more than a certain amount of ram, or could we be lucky and find it autodetects?

- be careful, some of the sites which have pictures of the SL-5500 internals are actually showing the SL-5000 (32 mb chips)

32MB SL-5500s do exist, I have one and as you might imagine am quite interested in a RAM upgrade.   I'd imagine you'd see more of them on Japanese sites as they seem to get a lot of hi-tech stuff earlier, and what with Sharp being a Japanese company & all.

- has anyone seen a CF card that uses SRAM instead of flash?  This would make a nice swap file

It would. I personally know a little more about what goes onto the silicon than I do about what's currently selling in electronic retail, so excuse me if this seems to be a foolish question but is SRAM actually used in any medium-to-high-capacity general purpose storage applications? I'm asking because iirc SRAM cells take more than twice as much chip space as DRAM or (presumably) flash cells, so I don't really think a manufacturer would use them where the primary design goal is maximum capacity for your money. More's the pity if I'm right.

[bsaunder2002]

Yeah, from what I understand regarding SRAM, it takes batteries(not as much as DRAM but still takes em), and it's very large as far as gate count goes....

so that leads to...

flash last forever without batteries

dram fits a lot more memory in the same physical space

so SRAM looses out...in fact I cant think of any other use for SRAM based CF other than swap file(unlimitted write capability)...

So I doubt we'll ever "buy" one of these but I'd love even 32mb of SRAM CF...

Someone know how to make a CF card?  Cant be too difficult...

-------------------------------

In regards to the bootloader...

I saw the statement "extra memory needs rewriting the bootloader" in an email.

BUT

The c700 64mb to 128mb page implies that only the kernel would need hacking.
(my japanese isn't too good)

The c700 site has pics of the upgrade.  The mem chips on the Cxxx? machines appears to BGA(ball grid array) and look to be a bxtch to upgrade.  The 5?00 would be much easier as they are just surface mount pin based chips.  

I cant find anything about a zaurus being upgraded with pin based chips BUT there used to be some ipaq upgrade do it yourself sites.  Those sites would at least show the method.  Also the pocketpctech guys advertise/brag about their "stacked chip" method where they piggy back the memory chips.  That sounds even easier than trying to remove the originals(wave soldering isn't easy).

Oh well...I'd love to fix this problem but we need more organization...I have too little time/knowlege to lead this fight...

Just think though 128mb with a hacked in EA-BL08 battery... sweet 4 hours run time rocken mem... drooling now...

[eekee]

Ah boy, you got me drooling too. I hope stacked chip is possible on the 5x00s, will open up mine sometime soon & have a look. As to making an SRAM CF, the specs for CF must be somewhere on teh intarwab, I may have a look for them sometime although even as a DIY project I don't suppose an SRAM CF would be particularly cheap. I don't know that for sure though, so perhaps I should keep my mouth shut until I've found out. Thinking of pinouts has lead me to another thought, although it's a bit of an idle one: perhaps the Z's CPU has some unused ports that could be used for SRAM read-write. It would mean the CF port would still be free for wireless & whatnot, but there's several reasons why this might not work or be worth it.

Btw my Z is 64MB, my mistake. Still interested in an upgrade though.

[niv]

I still didn't gather enogth knowladge to answer te simple question:
Can the cpu "see" 8 banks of memory? if so, how does it work?

[bsaunder2002]

I still didn't gather enogth knowladge to answer te simple question:
Can the cpu "see" 8 banks of memory? if so, how does it work?
[div align=\"right\"][{POST_SNAPBACK}][/a][/div]

hmm...I don't know if I understand this but I think the answers in here...
The memory and PCMCIA control module (MPCM) supports four banks of fast-page-mode (FPM), extended-data-out (EDO), and/or synchronous DRAM (SDRAM). It also supports up to six banks of static memory: all six banks allow ROM or Flash memory, each with non-burs or burst read timings. Additionally, the lower three static banks support SRAM, the upper three static banks support variable latency I/O devices (with the variable data latency controlled by shared data ready input), and the lower four static banks support synchronous mask ROM (SMROM). SMROM is supported only on 32-bit data busses. All other dynamic and static memory types and variable latency I/O devices are supported on either 16-bit or 32-bit data
busses. Expansion devices are supported through PCMCIA control signals that share the memory bus data and address lines to complete the card interface. Some external glue logic (buffers and transceivers) is necessary to implement the interface. Control is provided to permit two card slots with hot-swap capability.
-------------------------
so what have we got in the Z...
16mb ROM  in 2 chips ?
64mb SDRAM in 2 chips

So maybe the ROM is stored in some of the "six banks of static memory".
and
The SDRAM is stored in some of the "4 banks bla bla bla"

So the 2 SDRAM chips, do they implement 4 banks or only 2?
(it makes sense that maybe they're using all 4 banks cause SL-5000 = 32mb, the SL-5500=64mb)

[a href=\"http://www.halfsane.com/zaurus/hw/DSC00843.JPG]http://www.halfsane.com/zaurus/hw/DSC00843.JPG[/url] shows
TC59SM716ASL-80
BUT IT DOESNT LIST THE ZAURUS MODEL NUMBER

http://www.tekprosystems.com/zaurus/internals.htm
shows the same pictures but lists the model as SL-5500

hmm, downloading the TC59SM716 data sheet from http://www.chipdig.com shows the chip has the following configurations:
2,097,152-WORDS × 4 BANKS × 16-BITS
4,194,304-WORDS × 4 BANKS × 8-BITS
8,388,608-WORDS × 4 BANKS × 4-BITS

now 64mb is mega bytes not mega words

so 2mw of 16bit words * 4 banks = !!!16 mega bytes!!! 2mb*4banks*(16bits/2)
guess what so does 4mb*4 and 8*4 / 2  (since it takes 2 4bit words to make a byte)

Now the SL-5000 has 32mb SDRAM and 2 chips guess what 16 megabytes * 2 chips equals...you're right 32mb.

My guess is the second website is incorrect and is showing pictures of a SL-5000 NOT a SL-5500.

Anyone have real pics of an SL-5500?

Dont think I need them though...here's why...
there is a TC59SM816 and it's datasheet says
4,194,304-WORDS × 4 BANKS × 16-BITS
8,388,608-WORDS × 4 BANKS × 8-BITS
16,777,216-WORDS × 4 BANKS × 4-BITS
doing the math 8mw(8bit words)*4 banks*2 chips = 64mb of RAM ie the SL-5500

Now that does answer one of the questions from above:
The zaurus SL-5500 thinks it's seeing 8 banks of RAM when it has 2 chips.
But this is weird since the SA-1110 says it only handles 4 banks of SDRAM funny...
Maybe the memory interface is 16bits then 8mw x 4 banks x 8 bits x 2 chips would equal 64mb of memory on a 4 bank system...

Bad news...there's no such thing as a TC59SM916... what to do?

well these are 256mbit chips...I wonder if a 512mb chip exists...

from the description "Type = Sdram ;; Density (Mb) = 256 ;; Geometry = 16M X 16 ;; Refresh = 8K/64ms ;; Features = PC100/PC133 ;; Power = Standard/low ;; Date = 2001-02-01"
I'm guessing some 256mb (8 chip) PC100 or PC133 memory used these... Maybe there are some 512mb PC100 mems that my work...

So I've run out of steam...what are we left with?
1- can the existing memory be replaced with higher density 512mb chips? who would make them? how hard would it be to solder them?

2- what does a SL-5500 look like on the inside...I'll find out tonight...

3- are there other SA-1110 PDA's that have had their memory upgraded beyond 64mb?  Easy question someone check time2tech and pocketpc tech to see...

4- how does stacked memory upgrades work, how much room is in the sl-5500, can this be done with the sl-5500...need to look up some of the DIY stacked memory upgrades for any pda to see if it explains it

anyone wanna help?
Bill

[bsaunder2002]

More info...looks like the SA-1110 will max out at 128mb RAM...ie natively usable without some funky bank switching...
so 128mb is much nicer than 64mb

hmmm now to stack or to replace...

comes from http://www.intel.com/design/pca/applicatio...q/sa1110faq.htm
> Question: In the system memory map (figure 2-3) for the SA-1110, the total address space is given as 4 Gbytes. The boot sector address range is 0x00000000 to 0x07FFFFFF, which is 128 Mbytes. But the address bus only carries address lines from A25:A0, which gives only a total of 64 Mbytes. Where is the 27th address line?
> Resolution: A26 is an internal address bit that is multiplexed onto DRA9 at CAS time, giving the 27th bit required to address 128 Mbytes of DRAM address space. This is shown in the first line in Table 10-8 DRAM or SMROM Row/Column Address Multiplexing, SA-1110 Microprocessor Developer's Manual.
> A26 is also brought out to a pin as nPREG. It can be used just as any other address bit to decode any chip select space.
> so it looks like 128mb is the max DRAM...unless you do some software driver
> this matches up with the pocketpctechs 128MB max "native" and 256MB using a special driver

[bsaunder2002]

hmm page 152 of the dev manual:
   The SA-1110 supports most x4, x8, x16, and x32 SDRAM.

hmm wonder what they mean bu x4, x8, ... banks? word size?

[bsaunder2002]

oh yeah page 120 shows a "General Memory Interface Configuration"
it shows 4 DRAM banks of either 16 or 32 bit wide memory
so I'm guessing 4 banks is all we get...

anyone got any 512Mbit SDRAMs they wanna loan me?

really though, anyone have a busted screen Z?  ie still works but screens messed up.  Need it to test on...

[bsaunder2002]

ok where to start...
well I bought a broken SL-5500...$25
screen's toast
came with battery, maybe I'll get something out of my money
plug it in, battery light comes on, but without a CF card in it C+D+reset doesnt light any lights up
maybe I should have tried with a CF before I disassembled...

ok so the bad news...
Samsung k4s561633c-rl75 two of them

why is that bad news?
can you say "CSP"
can you say "worse than BGA"

So what did we learn?
http://www.halfsane.com/zaurus/hw/ doesnt say which model the pictures are of and my guess is that it's a SL-5000D
and
http://www.tekprosystems.com/zaurus/internals.htm says it's a SL-5500...BUT though it looks very very similar, the picture http://www.tekprosystems.com/images/zaurus/zguts1.jpg shows 2 memory chips of 16MB size not 32MB size and they have pins(damn them) whereas mine have CSP chips(double damn them).

What's Sharp got against a 128mb hand held?

It might be easier to upgrade a 32MB SL-5000D to 128MB than to take a SL-5500 to 128MB...

I thought you could but...this will probably not be a DIY memory upgrade.

www.pocketpctechs.com has told me they'd do it but the kernel/bootloader had to be rewritten.
I still have the email address if anyone has $200 they want to spend...

so I'm giving up on the memory expansion...

the next question...can I rig up the CF slot so that a single slot can support a GPRS modem or WiFi card and a microdrive...  (notice the modem part there are no combo flash/gprs modem solutions)

or possibly hack in the USB host somewhere but it'll be too slow...

oh the delima...

[niv]

wow! bsaunder2002

cheers mate for all that info. I am sure it would come in handy in the future as I may want to upgrade my simpad.

Thanks,
Niv