Author Topic: Type of micro SD cards  (Read 4851 times)

Offline neil

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Type of micro SD cards
« on: April 01, 2015, 12:03:30 PM »
Hi Mark,
  We are using micro SD cards with our system, and works well. We have a client that purchased 3 8GB Sandisk HC1 (I attached a snapshot of it) cards.  When they format them in windows is says approx 8GB, but when they put it in the board it says 4GB approx .  Sometimes (cant remember if straight format from windows, or after the board does a format) it doesnt read the card correctly, it says 0GB.   

I know version 2 of the cards are required , but when a client asks what type of micro SD card (HC etc), and max capacity, what is the best thing to tell them?

Regards
Neil
« Last Edit: April 01, 2015, 12:47:15 PM by neil »

Offline mark

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Re: Type of micro SD cards
« Reply #1 on: April 01, 2015, 09:45:43 PM »
Neil

At the moment I don't have any information about cards that cause problems. I also have 8G SanDisk HC cards with a (4) [in a different place].

Is it possible to see a directory listing from one and also the "info" data read? Afer formatting with Windows and after a re-format? I can compare with the outputs that I get from the same sized card and this may give some indication as to what may be the difference.

Regards

Mark

Offline neil

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Re: Type of micro SD cards
« Reply #2 on: April 01, 2015, 11:15:48 PM »
Hi Mark
   unfortunately my customer is in Australia so it might be a while till I get the card.

Regarding what type of sd micro card they can purchase (not the brand , but just types) along with max capacity , what are the different types that are comparable with uFat (spi)?  I see there are many different types out there

regards
neil

Offline mark

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Re: Type of micro SD cards
« Reply #3 on: April 02, 2015, 05:57:44 PM »
Hi Neil

I understand that there may be some new, high speed cards that no longer support SPI mode of operation but I haven't encoutered one myself yet. However, as long as the SPI mode is operational there are no further restrictions as compared to working in SDHC mode - it is only the FAT operation that may restrict since the largest single file possible is 4G.

This means that up to 4G there are no restrictions and above there is the maximum single file limit for FAT32 but not restricted to any interface type

Therefore I would suggest that there should be no problems that are SD card size related and also not due to the interface, assuming that the manufaturer hasn't dropped the SPI mode support (unlikely).

I did (some time ago) buy a very high speed 32G, top of the range card hoping that I could test a card that had dropped the SPI mode but it still worked...

Regards

Mark