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P2 with Legacy SD Cards — Parallax Forums

P2 with Legacy SD Cards

This discussion was created from comments split from: P2 Evaluation Board - Brief Update December 18th.
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  • Cluso99Cluso99 Posts: 18,066
    localroger wrote: »
    My P2-Eval came today. Had a brief moment of concern before I realized my micro-USB cable was inadequate and got a thicker one. Now all the simple tests done, need to try some of the more elaborate ones. Might need to buy a micro-SD card tomorrow as none of mine are SDHC / FAT32.
    Presume you have older SD with FAT16 or FAT32? Could you give them a try please?
    The booter should actually work with older SD cards. Not sure if I removed the variation for FAT16 support. Won't be home till the w/e and have some catching up to do then.
  • evanhevanh Posts: 15,126
    Bet he meant that they're SDXC/exFAT.
  • The card I tried that wouldn't mount was VERY old, only 32 Mb, and called TransFlash instead of SD. Even if your driver supports FAT16 it also has to properly detect the difference between SD and SDHC, which shift the sector pointer 9 bits to provide for a larger address space for SDHC. The original Prop1 drivers wouldn't do SDHC at all, and if yours does SDHC, do you know whether it's doing the test to detect plain old SD?
  • Cluso99Cluso99 Posts: 18,066
    edited 2019-01-03 05:31
    Yes, it does the test, and I did test this at one stage. Just not sure about the FAT16 part.

    SDXC as exFAT needs the boot code in the MBR (ie sector 0). Pretty sure that SDXC as FAT32 works fine.
  • Wait a minute. How can you get an old SD card in microSD format?

    I have a bunch of SD cards but there all full sized. I have a 128Mb card that I use to load my 3D printer with but it's full sized.

    Mike

    PS my 3D printer with an Arduino controller running Marlin can read long file names just fine.
  • If we use an adapter, an old SD card can end up connected.
  • Never seen one of those things. Only a microSD adapter to SD.

    Mike
  • Cluso99Cluso99 Posts: 18,066
    edited 2019-01-03 12:21
    We are referring to microSD cards.

    However, it is possible to build an adapter to go the wrong way, but why???
  • Wait!, I found and old 2gb micro SD card formatted as FAT laying around.

    Will that work?

    Mike
  • TorTor Posts: 2,010
    I have a couple of SD-to-microSD adapters (not microSD-to-SD) laying around. I bought them from DX IIRC. It's essentially an SD card holder with a little flat ribbon and a microSD-shaped plug at the end.
  • I have an 8 track player laying around too. Probably just as useful.

    Mike
  • The 32mb TransFlash card I tried is in microSD form factor; it fits the P2SE socket, no adapter required. I speak of SD and SDHC protocols because those are the same for full-size and micro-SD. There were some compatibility issues with drivers favoring older or newer cards back when SD support for the P1 was originally being developed. You can't get these low-capacity cards new any more obviously; this is one I salvaged from a really old digital camera.
  • Tor wrote: »
    I have a couple of SD-to-microSD adapters (not microSD-to-SD) laying around. I bought them from DX IIRC. It's essentially an SD card holder with a little flat ribbon and a microSD-shaped plug at the end.

    I do too. I currently use one to make handling Micro SD easier. Insert adapter cable into Micro SD slot. The adapter takes full sized SD, meaning an old, or new / Micro SD can be connected. MicroSD gets put into one of those full sized cards that can hold it.

    I also have one of those full sized "carriers" in my laptop, so I can easily insert Micro SD, and so I don't lose either.


  • And verified, a new SanDisk 16Gb uSD mounts and functions fine.
  • Cluso99Cluso99 Posts: 18,066
    iseries wrote: »
    Wait!, I found and old 2gb micro SD card formatted as FAT laying around.

    Will that work?

    Mike

    It's probably FAT32. Give it a try and let us know. Copy your test file and name it "_BOOT_P2.BIX" (case sensitive).
  • Cluso99Cluso99 Posts: 18,066
    edited 2019-01-03 17:36
    localroger wrote: »
    The 32mb TransFlash card I tried is in microSD form factor; it fits the P2SE socket, no adapter required. I speak of SD and SDHC protocols because those are the same for full-size and micro-SD. There were some compatibility issues with drivers favoring older or newer cards back when SD support for the P1 was originally being developed. You can't get these low-capacity cards new any more obviously; this is one I salvaged from a really old digital camera.
    That one may not work unless you reformat to FAT32. FAT16 may work but I just cannot recall what I stripped out for the ROM. 32MB might default to FAT12???

    BTW there has been offline discussion about not supporting cards below SDHC or SD V2.0? Thoughts anyone?
  • If doing that is a must, like feature trade-off, do it; otherwise broad support makes sense.

    An example might be say Peter can fit his TAQOS assembler in there, if legacy SD support goes...

    My .02
  • kwinnkwinn Posts: 8,697
    Cluso99 wrote: »
    localroger wrote: »
    ........

    BTW there has been offline discussion about not supporting cards below SDHC or SD V2.0? Thoughts anyone?

    Good idea. The time has come to leave the old inconsistent sd cards behind.
  • Cluso99 wrote: »
    iseries wrote: »
    Wait!, I found and old 2gb micro SD card formatted as FAT laying around.

    Will that work?

    Mike

    It's probably FAT32. Give it a try and let us know. Copy your test file and name it "_BOOT_P2.BIX" (case sensitive).

    I have an old 2BG Kodak uSD that I reformatted to FAT32 and it boots fine. I have been using a SanDisk HC 32GB since I got the P2-ES.
  • jmgjmg Posts: 15,140
    potatohead wrote: »
    If doing that is a must, like feature trade-off, do it; otherwise broad support makes sense.

    An example might be say Peter can fit his TAQOS assembler in there, if legacy SD support goes...

    The ROM is always going to have a hard ceiling, and involve trade offs.

    For 'nice to have' features like TAQOZ assembler, as well as Spin 2 etc, it may be smarter to allow a ROM-Patch area in FLASH ?
    (In the scheme of things, FLASH is quite cheap)

    ie during boot, it looks at flash to see if a) present and b) has valid ROM patch, and if so, it loads that too.
    To the user, it appears like a larger Flash ROM, and they can download and upgrade that firmware area of Flash on a semi regular basis.


  • Well, we could all put our opinions out there. I would definitely trade a more robust ROM feature for legacy SD cards, or other options that can further complicate an already complex boot process. But, that's me. We shall all see how it shakes out in the end.

  • Publison wrote: »
    Cluso99 wrote: »
    iseries wrote: »
    Wait!, I found and old 2gb micro SD card formatted as FAT laying around.

    Will that work?

    Mike

    It's probably FAT32. Give it a try and let us know. Copy your test file and name it "_BOOT_P2.BIX" (case sensitive).

    I have an old 2BG Kodak uSD that I reformatted to FAT32 and it boots fine. I have been using a SanDisk HC 32GB since I got the P2-ES.

    I formatted the 2GB for default (FAT16? or FAT?) it did not mount. Reformatted for FAT32 and it will not mount anymore. 2GB may not be a good choice.
  • Cluso99Cluso99 Posts: 18,066
    Publison wrote: »
    Publison wrote: »
    Cluso99 wrote: »
    iseries wrote: »
    Wait!, I found and old 2gb micro SD card formatted as FAT laying around.

    Will that work?

    Mike

    It's probably FAT32. Give it a try and let us know. Copy your test file and name it "_BOOT_P2.BIX" (case sensitive).

    I have an old 2BG Kodak uSD that I reformatted to FAT32 and it boots fine. I have been using a SanDisk HC 32GB since I got the P2-ES.

    I formatted the 2GB for default (FAT16? or FAT?) it did not mount. Reformatted for FAT32 and it will not mount anymore. 2GB may not be a good choice.
    I tried a number of 1, 2 & 8GB cards w/o problems. When I get home I'll post a test program so we can find out why boot fails. If I forget, please remind me.
  • On the TransFlash drive that wouldn't mount, Windows reports it (via a USB adapter) as being FAT as opposed to FAT32. I am pretty sure that means it is FAT12.
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2019-01-05 14:15
    Can't we just leave these old SD cards buried rather than digging them up again and trying to reanimate them? Even the cheapest nastiest microSD card today is much better than any of these FAT16 Frankenstein zombie cards that have probably been pushed past their Flash endurance lifetime many many years ago.

    I can walk into Officeworks here in Oz and pick up a 64GB SDXC for $22 and I can't find any cards smaller than 16GB. Surely nobody is serious about using the brand new P2 with a worn out veteran card? Well, not at the expense of ROM I hope.
  • You are probably correct Peter. I'll use my 2GB for wave files on some player P1 projects.
  • Pretty much any low capacity SD card (and I think eMMC, too?) will adhere to ye' olde original SD standard. While for tinkering around, getting an SDHC/SDXC card is no issue, someone mass producing something might shave some margins by being able to use some nasty 512 MB micro SD to store their firmware or whatever (vs. a more expensove larger card or a flash ROM that needs to be soldered down and would require special equipment to write). Random nasty SD cards inside the case are actually more common than one would think.
  • kwinnkwinn Posts: 8,697
    Cluso99 wrote: »
    localroger wrote: »
    ......

    BTW there has been offline discussion about not supporting cards below SDHC or SD V2.0? Thoughts anyone?

    Good idea IMHO. Having extra code and support problems to support low capacity & speed cards is a waste when the lower capacity new sd cards available today are so inexpensive.
  • I think we'd want to have the widest SD support possible. It's always annoying to have to have to start explaining to people what kind of card they need, and why they can't just use whatever microSD card they have in a drawer that was pulled out of an old phone.

    I thought the current boot code already had relatively wide support for current and future cards?

    Does the current code work with SDXC cards? I built a board that *only* worked with original 1GB or less 'SD' cards recently, and tracking one down was a pain. Already I am seeing more SDXC cards on the market, and less SDHC cards. A big problem there is that they tend to be large enough for default to exFAT....and it's a PITA in Windows to format them as anything else.
  • Please don't confuse the words "want" "like" "think" etc with "best". Specifically we are talking about support for SD boot in the BOOT ROM which does not preclude anyone connecting a floppy drive or a punch tape reader that happens to be lying around. So "widest" support is also not the best either. Old cards "may" still (just) work but their performance can be abysmal compared to any new cheap card you can pick up from the bargain bin. The P2 chip itself is not just any chip we happen to have lying around. We are not supporting serial EEPROM boot either yet I have reels of brand new ones I "could" use.

    As for formatting larger SD cards I believe we can do that easily enough with the P2 itself rather than depending upon MS to do it for us, and besides I'm a Linux man myself and there are Mac people here too, so we don't have that MS problem. I will write an SD formatter for TAQOZ that may be pasted in through the terminal to format a card. Alternatively it can also be backed up onto the serial Flash.

    I think if we could walk into a store and buy 2GB cards then perhaps we should consider support for these, but it has been many many years since that was even possible and now I find that the smallest card I can find in a store is 16GB.
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