SD Card mystery
Don M
Posts: 1,653
I purchased 10 2GB uSD cards off Ebay recently. I received them Friday and went ahead testing them with my PropBOE board using Kye's test program included in his Fat 16 object in the OBEX. I also was using Duane Degn's simple test routine that he posted recently.
I have not tested all of them yet but of the 4 that I did test I found that 50% of those would not work with the test routines or they might mount but then quit. These are all Sandisk brand cards and look to have never been used as the gold fingers are clean of scratches.
I tried re-formatting them both with Windows and the formatter found on the sdcard.org website. Formatting made no difference. What is puzzling is that these cards work fine with the PC. I can save programs, read programs and see the directory. Using checkdisk on the PC all show no problems and the correct amount of available sectors, etc. available.
I also have a 2GB Sandisk card that I bought locally at a store. It works fine with the Prop test programs and comparing the info from that card with the other cards does not show any difference. I bought 2 cards from the Walmart website which are a Wintech brand card. They too work fine with the Prop test programs that use Kye's fat engine.
For the heck of it I thought I'd try the FSRW object and tried some sample code from OBC's gadget gansters tutorial. To my surprise ALL the cards work ok. I have a project that I am working on that will use the uSD cards for data logging and I am using FSRW and it seems to work OK with all the cards.
So I know that you may question the Ebay purchase and the quality of those cards but it seems puzzling that one driver will work but not the other. The cards look as new but how would you know if they were rejects? How is one able to reliably purchase / test cards? Does the fact that they won't work with Kye's driver make them bad?
Are there any more stringent tests available that someone has written using FSRW that I could use?
Here are the cards I bought: http://www.ebay.com/itm/250987330642?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_4075wt_1143 They were on sale when I bought mine for $1.99 each. Comes with SD card adaptor.
Thanks for any help.
Don
I have not tested all of them yet but of the 4 that I did test I found that 50% of those would not work with the test routines or they might mount but then quit. These are all Sandisk brand cards and look to have never been used as the gold fingers are clean of scratches.
I tried re-formatting them both with Windows and the formatter found on the sdcard.org website. Formatting made no difference. What is puzzling is that these cards work fine with the PC. I can save programs, read programs and see the directory. Using checkdisk on the PC all show no problems and the correct amount of available sectors, etc. available.
I also have a 2GB Sandisk card that I bought locally at a store. It works fine with the Prop test programs and comparing the info from that card with the other cards does not show any difference. I bought 2 cards from the Walmart website which are a Wintech brand card. They too work fine with the Prop test programs that use Kye's fat engine.
For the heck of it I thought I'd try the FSRW object and tried some sample code from OBC's gadget gansters tutorial. To my surprise ALL the cards work ok. I have a project that I am working on that will use the uSD cards for data logging and I am using FSRW and it seems to work OK with all the cards.
So I know that you may question the Ebay purchase and the quality of those cards but it seems puzzling that one driver will work but not the other. The cards look as new but how would you know if they were rejects? How is one able to reliably purchase / test cards? Does the fact that they won't work with Kye's driver make them bad?
Are there any more stringent tests available that someone has written using FSRW that I could use?
Here are the cards I bought: http://www.ebay.com/itm/250987330642?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_4075wt_1143 They were on sale when I bought mine for $1.99 each. Comes with SD card adaptor.
Thanks for any help.
Don
Comments
My driver can reject cards for all sorts of reasons. It doesn't mean that they are bad. If reformatting the SD card using a "non-quick" format does not make a difference then my driver is incompatible with the SD card.
If FSRW works go with it. If you want to know what problem my driver has with the sd card then print out the error string returned by the file system method call. If you get "Disk IO Error" then my file system driver has some problem with the SD card itself and reformatting will not fix the issue.
FSRW is more tolerant of out of spec SD card behavior...
Thanks,