Anyone working on Sig3 Linux?

No sign of jax then.

Hopefully he will be along soon

John

Just found out my work mates wife if a production line manager in an electronics firm who make circuit boards etc.

He reckons she will be able to just hand my spare Sig3 board to someone and get them to desolder and replace chips with either sockets or replacement chips in no time at all.. Certainly prefferable to me stuffing it up or getting some electronic repair monkey to try and break it.

So I really need to find out what sort of replacements I can use in the Sig3. I think flash roms would be better but I guess socketed replacements that can be programmed with a rom programmer if there are no flash suitable.

Is Jax the expert with this sort of thing? Either that or where else can I discover what replacement part it is best to find. Are the chips used in the 900C the same size and shape??? (both NEC devices, they are from about a similar era, both Xscales and we already have loads of knowledge on how to program them etc.)

John

The Sig's ROM chips are BGA chips, so they're not the sort of thing that can be desoldered and replaced by just anyone. Instead of pins along the side where anyone with a soldering iron can attack them, they use balls of solder on the underside. It takes special equipment to work with them.
But it IS possible to replace them, if we can find someone so equipped.

Even so, I don't think we'll be able to rig up a socket for easy swapping. Certainly not a socket for BGA chips. It would be quite the hack. So with that in mind, we'll need to flash the new chips with a reliable bootloader before installing them, making sure we have a way to load test builds of the OS without removing the chips again.

This doesn't even touch the issue of finding a compatible chip. You can't throw just anything in there and expect it to work. I haven't looked for something that would work yet, so I don't know what we'll find.

The person I can get to look at this works for an electronic circuit board manufacturer so I would think the have the equipment as they also do development and design work as well.

So first, and I am totally lost here, we need to find suitable flash replacements.

John

Edited by mr-mac 2008-01-10 3:49 PM

Other question, which is likely a non starter.... Is there a socket that has a BGA attachment to PCB but takes a chip with pins (either the pins that stick down or the sort where socket surrounds chip and contacts are made round the chips edge)?

I'd forget this as a distraction at the moment.

You need to get the linux kernel booting first, then sort the drivers out. This can possibly be achieved with HaRet, and does not require flash chips or the like.

Working on getting something working in software using a loader as used by the 720 distros is the way forward, with flash boards as a distant future dream. If you want to get linux working, don't put unneeded roadblocks in the way!

I still think the Sig is the perfect form factor device, beating the netbook pro and the Asus EeePc - however, when the eeepc gets a decent screen then things might swing its way

well, we can use the existing bootloader but we'll need to implement flashing routines in it, for that, having the full source code would be much preferred to reversing the compiled binary and reimplementing all of it in C/C++. but oh well.. and then, the hardest part is the actual flashing routines (and probably some pcmcia routines), that has to be working, the rest can be stolen from eboot sources, i mean the download process (via ethernet for example - unless you want to load it from CF/SD card, then even more work is needed).

no worries though, you should be able to load the beta bootloader images in RAM to test (if you write them properly), instead of removing the flash chip everytime to flash with the next version of the bootloader.

so first i'd say just flash the existing bootloader and existing OS before soldering the flashrom in. so it should be bootable just fine and then you can test later. but in this case you'll want NOR flash definitely, not NAND. you don't need a driver for NOR.

a more professional way is, work out jtagging (if possible) and access it that way after soldering the flash in place. if not possible, then you'd need a real development board where you can directly program the flash... :/

Edited by cmonex 2008-01-11 7:01 AM

chiark: if the eee pc gets smaller and better battery / more instant on, then yeah

as for linux yeah good idea, would be easier probably

But why flash anything?

Surely if there's a project to be done it's to get it booting out of RAM, or of CF or SD, like we can do for the 720, 680, ...?

I'm genuinely confused why any flashing would be needed to get Linux working on this.

It started out as linux topic but my idea for flash rom is actually more for other reasons.

1st it will allow a full English version of CE .net 4.1 to be installed.

2nd I can replace patched and updated files with the new ones in rom.

3rd I can maybe drop some useless programs and pop in replacements.

4th It may be possible to install CE .net 4.2

The above are really my main aim rather than anything to do with linux - though this idea actually was started with the initial discussions in this thread.

John

Edited by mr-mac 2008-01-11 7:17 AM

We really need to get Stingraze to email the person you found in the bootloader to see if we can get anything (like bootloader source code).

I would have thought the development/test Sig3 would have had flash in it for use when they were building the CE platfrom (they would have needed to test and re-build the rom a number of times before it was fully working). So they may have info on suitable flash roms and a bootloader that will allow flashing of them.

John

Just realise Chairk... Was it not you, on page 1, that said "but the Sig3 doesn't have flashable rom"...

Not making a point just thought it amusing.

That is the post that set me along my quest which is bound to fail.

Edited by mr-mac 2008-01-11 7:28 AM

- aye, that was me . Ultimately, it would be great if we could have it in flash, but we can't (without seriously hard engineering work that's just not accessible to anyone outside of rather high end SMD engineering places).

It just seems like we're putting obstacles in the way of Sig3 linux that we don't need

The linux discussion started me along my current path but I am not doing it specifically for linux. Mainly to allow me to update and do custom roms.

Maybe I should take this as a side topic and Start it's own post now. Then any linux discussion can continue here as I am quite keen to see linux available on the Sig3.

John

I have emailed the address in the bootloader with a very quick 2 line email just asking if he speakes english and if "yes" if it is ok to ask some questions about the Sig3.

So far (after 40min) I haven't had my email returned undeliverable so I will keep my fingers crossed. I want to ask him if they used a flash rom in development. If they did try and get some details and maybe see if we can get bootloader source and/or a bootloader with flash support built in.

However, I guess rather than loads of people emailing him I could ask about anything that would help with linux as well. I guess 1st off one thing we may need is details on what chipset drives the touchscreen and maybe some tech spec on the ASIC chip.

If I get no response or he doesn't speak English I guess, again, asking Stingraze nicely will probablly be the best route...

John



Edited by mr-mac 2008-01-11 8:12 AM