Is there such a thing as a micro SD to RS-MMC adapter?
 

When I see things like this:

Micro/Mini SD adapter, it makes me wonder if a micro SD (transflash) card could be adapted to RS-MMC (MMCm) size.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

I maybe wrong but my understanding is that SD speaks on a completely different protocol than RS-MMC / MMC Mobile, as well as having different contact locations

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

No, SD is basically a superset of MMC. SD has 4 data bit contacts while (old) MMC has 1, but SD interfaces can talk in 1-bit mode too. Newer MMC (MMC Plus) again have more contacts than SD, but all these interfaces can still interchange the cards. I believe the Reduced Size versions of MMC are just that, reduced size, but otherwise the same as MMC (sometimes there are reduced voltages as well, but interfaces can still work with all of them if made that way).
Look no further than the N800, which (with adapter, this is just for handling the different physical sizes) can handle the full range of SD/MMC/RS-MMC/mini-SD/micro-SD/MMC Plus.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

I think Tweak was right about the protocols being different. SD devices offer backwards compatibility to MMC, but MMC devices can't use SD cards. An adaptor would make a RS-MMC sized SD card that went into MMC device. I think you would need some serious circuitry to make that work and it definitely would be bigger than the difference in physical sizes of MicroSD and RS-MMC. Just my .02

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Hm, I think you're right. I was only thinking about SD being compatible with the rest, not the other way around. On the other hand.. there are simple SD interfaces that actually read SD cards just as they would MMC cards, that is, through a 1-bit serial interface. I'm not certain if this means that MMC could read SD cards or not.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

SD is backward compatable with MMC. So a MicroSD to RSMMC converter would work if such a thing existed. I've attached an SD card to my n770 and it works fine.

http://linuxjunk.blogspot.com/2007/0...d-sd-card.html

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

All you need now is a SDHC kernel patch for the 770 and you can plunk in an 8GB card monster.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

I can't speak for the n880, but doesn't the door on the 770 have to be closed in order to mount the memory card? That kinda screws any sort of adapter.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

If you read the mod, you'll find a mini-howto (of the sketchiest of sorts, however!) on how to short out the door thingie.

In fact, with that door mod I think the 770 would accept regular SD cards without further soldering. They'd stick out of the 770's body, of course, making all sorts of useful things obsolete, like, oh: Portability, the use of the cover... But hey! You too can have a 4GB (with a non-HC card) 770!

I wonder... Isn't there some stuff inside the 770 that can be dremeled away, so the card slot can be moved up? Do we really need the CPU?

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

In fact I have such kernel almost ready. Not sure about stability but week ago I tried to backport mmc stack from N800 kernel (including SDHC, high speed SD and >4GB MMC cards) to latest n770 2.6.16 and after all changes it still works with kingston 2gb mmc just fine. But what is more interesting for me is that this code from n800 kernel makes my transcend 4GB mmcplus card not working in n770 just like it doesn't work in n800 now (but works fine in n770 with 2.6.16 kernel). So now I'm in the process of merging changes again one by one and checking where it breaks. I thought N800 has some HW problem with this card but now it looks like it can be hopefully fixed in software. But if anyone wants to test this kernel with (high speed) SD or SDHC card in n770, let me know.

I was thinking about this SD mod for some time too, 4gb or bigger card in n770 would be nice and I don't remove the card anyway. I was reluctant to kill my only N770 with this mod and was also waiting for 4GB mmcmobile cards (which would make this mod pointless) but now I've got spare N770 one from expansys so I can start modding too :-)

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

yes with Nokia kernel, no with custom kernel with one line fix, waiting for closing the door is software 'feature'. Just comment line 694
in drivers/mmc/omap.c to make it check for cards also with doors open.

I have Transcend 4gb mmcplus card and it works in n770 without any hardware mod with doors opened and kernel with this one line fix.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

It's dremel time then? :D

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Okay, I'm desperately trying to understand this...

Does this mean that if I were to use your SDHC-patched kernel in my N800 (still on working firmware, so not the latest one!), I couldn't use my non-HC 4GB cards anymore?

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Well mmcplus one is thinner so there is no need but I was thinking about cutting the 4gb card to half to make it fit ;-) But I guess I'd end with two 2GB pieces so there is no point since I already have 2GB mmcmobile card :-) But maybe leaving a bit longer piece and removing the door could give me 3GB?

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

No, we are talking about n770 kernel here. I have 4gb mmcplus card that works in n770 (with doors open) but doesn't work in N800 (mentioned also here http://intr.overt.org/blog/?p=49 ). But when mmc code is backported from n800 kernel to n770 one the card stops working in n770 too! Initially I bought this card for n800 but since it wasn't working there I moved it to my Zodiac and tried it also in n770. When I find what makes this card unstable in n800 I can use it in n800 again.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

The MMC socket is actually too thin for an SD card. I think I might try replacing it with a SD card socket at some point.

hmm, so the 4GB SD cards are MMC compatible? didn't know that. Might have to check this out... :)

The OMAP1710 in the 770 actually has two MMC ports so it should be possible to mount something like a microSD internally and then have a full size SD socket (with the card sticking out). Only problem is that I'm not sure if the second port is exposed anywhere on the 770 (and if I remember correctly the OMAP1710 is BGA so it may be impossible to get to the pins).

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

one of you mentioned that it may be possible for the slot to recognise

2 cards with the proper wiring .

If so and if I could get the proper wiring for it

It wouldnt be hard to make a rear mounted sd slot .

Any one with this knowledge willing to share ?

A small extrusion made on the outside of the case in back where the NOKIA

name is located seems like a perfect place to mold a sd housing.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Seems like the master slave to allow 2 cards are in pin 1 ,2 or 7

Any one wanna chime in ?


[IMG]http://img63.imageshack.us/img63/7792/untitledoo2.jpg[/IMG]

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

MMC doesn't have chip select so any mod would only be compatible with SD cards. We'd also need to find an appropriate chip select line. Can this just be a GPIO line? I dunno. We also would need to get an SD card driver in to the kernel (sounds like this has been done).

A nicer option would be to use the second MMC/SD card port on the CPU, but finding this might be problematic. Is support already present in the OMAP1710 kernel for the second MMC port?

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

on the pinouts.ru site it showed the mmc with the same connections

and chip select the same as sd

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

The MMCplus Application note (version 4): http://www.mmca.org/compliance/buy_s...MMCA050419.pdf says:

"The initialization procedure of MMCplus is equivalent to that of cards by standard version 3.31. The major difference is that any dedicated MMCplus host application is restriced to have only a single card slot (in order to cope with the increased frequency requirements)."

However it looks like standard MMC might be ok. Does anyone know if this is supported in the kernel?

The pinout for standard MMC according to the specification summary is:

Pin No. Name Type Description
1 RSV NC Reserved for future use
2 CMD I/O/PP/OD Command/Response
3 VSS1 S Supply voltage ground
4 VDD S Supply voltage
5 CLK I Clock
6 VSS2 S Supply voltage ground
7 DAT2 I/O/PP Data
Table 1: MultiMediaCard pad definition

from: http://www.mmca.org/compliance/buy_s...mary-v3.31.pdf

Doesn't have chip select, so may be it's done in the protocol?

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

I think there is a little confusion here. There are three modes of communication over SD/MMC slot.
- SPI - supported in theory by both mmc and sd cards, pins are explained for this mode on picture already mentioned, useful for some ancient hardware that can do only SPI
- MMC mode - only mmc cards can do this, preferred mode for MMC cards
- SD mode - only sd cards can do this, preferred mode for SD cards

Both SD and MMC modes are supported by N770 linux kernel, SPI not (for OMAP driver). Not sure about SD but at least MMC can have multiple cards connected to same bus (i.e. same pins). Cards have unique IDs and all listen to commands and only the one with correct ID responds to the command. SD maybe too (or maybe not) but anyway this mode is not regulary used and is now deprecated by MMC association. MMC high speed modes defined in MMC 4.x require only one card to be present. Also I think support for more cards is to be removed from linux kernel since it is really not used and only complicates things.

So to sum it up you may now connect more MMC cards to same pins but they will run in legacy MMC mode (max 20Mhz) and there may be bugs since this was never widely used. I'm also not sure about power requirements of such solution (i.e. if the slot in n770 can cope with powering two cards at once).
chip select is only for SPI mode, we probably don't want to use this and the pin is missing in N770 slot anyway. As for SD driver it is already present in the kernel.
No the support is not completely present due to missing hardware. If I understand it correctly having support for two slots in OMAP1710 CPU is not enough. You need additional hardware for powering up and driving the slot. Such second chip is missing for the second slot and if present in must be controlled from SD/MMC driver in linux kernel (i.e. powered up and down at right time) for the slot to work. Search this forum for both n770 and n800 schematics and see how SD/MMC slots are wired.

I think there are only two easy options to have cards over 2GB (current mmcmobile available maximum)
- wait for bigger mmcmobile cards (no problem with support for them)
- wire up >=4GB SD (regular,mini or micro) or MMCplus card to the slot.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Thanks for the info. I've connected 2 MMC cards ( http://linuxjunk.blogspot.com/2007/0...dual-mmcs.html ). And yep, they appear to work ok. Mind these are only 64 and 16mb cards so I guess I'm not drawing too much power from the 770.

However connecting a SD and an MMC at the same time only detected the SD. I thought SD should fall back to MMC mode if SD mode isn't supported but perhaps it's not supported for multiple devices. I might try connecting two SD cards and see what happens.

The stock tablet 2006 kernel? Is there any way to tell if the device is running in SD or MMC mode. All devices appear as mmcblkX to me, which doesn't tell me much.

ok, I guess the additional hardware could be added and the kernel patched if the pins are actually exposed somewhere. There are some pins next to the battery but I'm guessing those are probably JTAG? If anywhere they are probably under the metal shielding, I don't really fancy removing that right now.


Thanks for your help.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Didn't work, I get a bunch of CRC errors on dmesg and no cards detected.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

As explained twice in this thread SD cards don't understand MMC protocol so the can't fall back to anything.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Ah ok, I guess I got confused with them both being able to fall back in to SPI mode or something.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Yes. it is same driver as MMC. There is no high speed SD (50Mhz) and no SDHC support in stock tablet kernel but otherwise it is there.
Well with SD card inserted it is in SD mode, check is done at runtime.
You can browse source here http://lxr.linux.no/source/drivers/mmc/?v=2.6.18
main sources are mmc.c and mmc_block.c, OMAP specific lowlevel driver is in omap.c
Thanks for your tests. I was not sure more mmc cards would actually work, it is good to know it is possible and working.

OMPA1710 is BGA
 

A link:
http://focus.ti.com/general/docs/wtb...contentId=4670

However, that is not to say that there are traces going somewhere on the PCB.

I think an idea, that I have not seen in this thread, would be to make an insertable RS-MMC to SD adapter. Use a ribbon cable or flexible PCB or the like and mount a socket on the outside of the case. Or, if there is room within the shell mount the SD card somewhere within.

Hrmmm...

eb

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

The link to the pictures of the mod came out with a "0" instead of a "-" when I did a cut and past. The link that works is:

http://linuxjunk.blogspot.com/2007/0...dual-mmcs.html

It sure looks interesting! Yes, a little flex circuit sneaking past the lever-cover to some sort of expansion pack sounds interesting. To keep it in place all the time would require some sort of leather style booklet case with a reinforced front to protect the LCD. That way there could be a compartment or flap somewhere in the case for the external module(s) and the reinforced foldover front would do the job of the metal slipcover in protecting the screen. No magnet, though. It would be best for those not requiring super speed, just more storage, like MP3 files for example. Then of course there is always the possibility of a custom ASIC chip to serve as an MMC to Compact Flash Hard Drive interface. Maybe some kernel tweaks to make it work, too. :-)

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

I wonder modifying a small MicroSD to SD adapter would work. Surfing the net I come across a cheap adapter like this:

http://img515.imageshack.us/img515/9...0912sa7.th.jpg

One side of the adapter is the USB insert, and the other side is SD. Without the USB portion the length is around 21mm, slightly longer than the 18mm RS-MMC standard. Someone reported that it's a bit thicker than the normal SD card, and if you crack open the case it looks like this:

http://img528.imageshack.us/img528/7...0459al5.th.jpg

So if the case is removed, usb part is cut off, and glue a MicroSD onto the PCB, it might be thin enough and small enough to insert into 770's RS-MMC socket.

PS I don't want to spam the forum, so if you want to know where to buy it, google "Worlds Smallest 2-in-1 Trio TransFlash USB Card Reader".

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

http://2daughtersandablog.blogspot.c...nokia-770.html


For all you brave folk. I did this over the weekend and it works fine. Just used an SD adapter for a Mini-SD card and mounted it inside.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Link didn't work..

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

http://2daughtersandablog.blogspot.com/

sorry, this should work.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Good work, too bad you killed the door switch. :-) Also more photos of the procedure would be welcomed :-)

I am thinking about same hack for quite some time but so far had no time and when I had some I couldn't open the case
http://www.internettablettalk.com/fo...1295#post81295
:-) You had no problems with opening the case?

Well maybe killing the slot wouldn't be so bad after all but I would definitely want to leave the door switch working. How did you break it? Do you think it is possible to leave it working when being extra careful?

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Gotta ask: why would you want SD when RSMMC is cheaper, at least here in the UK?

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

you can't buy 4GB or 8GB rsmmc :-)

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

granted, that is good enough reason ;-)

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

RS-MMC is not as widely available here in the US. If you are extra careful, you shouldn't have a problem leaving the door switch attached. I also used my dremel to sand out some space on the inside of the back housing where the card is installed. the card slot came out pretty easy with a pair of small pliers cutting at each mount point. I was going to go get a usb micro-SD adapter to get the slot out of but didn't. I would have to look at the dimensions but I bet it would fit in there fine. Tonight I will post a picture or two with the card mounted inside, I don't recall if I took a picture of the back housing that I used the dremel on. Basically I just outlined the card where I was going to put it and cut out the supports for that section. If you've seen the inside, you'll know what I mean by supports. Also, if you can find thin wire, I would highly recommend you use it. There isn't a lot of room in there.

On another note, I did reinstall 2006 over 2007he and it seems to be a little more stable for me. I don't know what the speed differences are but I suspect the 2007he didn't like using virtual memory on my sd card. It seemed to slow things down.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

The bottom piece needs to come off before you start prying the two half's apart. Then you need to start at the top side or top. Once the top is apart the bottom needs to be unclipped while sliding the usb and power ports out of the slots. Use a thin piece of plastic to slide along the crack while prying. You should start unclipping connection points.

Re: Is there such a thing as a micro SD to RS-MMC adapter?
 

Will the 770 support that large of a memory card? I thought it was 2 GB.