Re: Is there such a thing as a micro SD to RS-MMC adapter?
Quote:
"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?
Quote:
- 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). Quote:
Quote:
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?
Quote:
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. Quote:
Quote:
Thanks for your help. |
Re: Is there such a thing as a micro SD to RS-MMC adapter?
Quote:
|
Re: Is there such a thing as a micro SD to RS-MMC adapter?
Quote:
|
Re: Is there such a thing as a micro SD to RS-MMC adapter?
Quote:
|
Re: Is there such a thing as a micro SD to RS-MMC adapter?
Quote:
Quote:
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 Quote:
|
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". |
All times are GMT. The time now is 09:52. |
vBulletin® Version 3.8.8