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Trouble with SD Card going idle

Created Sat, 29 Jun 2013 03:58:40 +0000 by micronut


Sat, 29 Jun 2013 03:58:40 +0000

I have an Uno32 and with the SeeedStudio V3 SD Card Shield I have no problem reading a SD card. When I wire Parallax's Micro SD Card Adapter [url][/url] to the Uno32 instead I get an initialization error which indicates that CMD0 did not get an idle response and timed out with the same SD card.

The difference I see in the two boards other than a voltage translation IC is that the Parallax board has pull up resistors (value not listed but I'm sure it is between 3.7K-10K) on all lines going to the SD socket and the SeeedStudio board does not. Can these pull up resistors keep the CS line high for some reason?


Sun, 30 Jun 2013 16:33:36 +0000

Looking at the boards, you are correct the pullups on the parallax board are 10k (it says R1-R8 are 10k), but another difference is the seedstudio board is using a voltage divider on the CS, DI, and CLK pins.

I wouldn't think that the pullups would hurt the communications though. Do you have a diagram of how you are wiring it? Is it possible you have the DI and DO crossed?


The SeedStudio also has much better filtering on the power lines. You may need a capacitor between you VCC and VSS rails.