SD card interface

prasobhp · ‎2007-05-10

Posted on May 11, 2007 at 05:15

SD card interface

prasobhp · ‎2007-05-01

Posted on May 02, 2007 at 07:18

Hi ,

I am trying to interface an SD card with DV 710B (Embest) based on STR710FZ2 . I am using same circuitry& code provided by ST for its STR711 USB ARM DEVELOPMENT PROTOTYPE BOARD but I don’t get any response from the SD card in the initialization process (after reset command).Sd card is perfectly all right when connected to the PC. HOW can I adjust the frequency to the required 400KHZ is there any mistake in my circuit.I am attaching the circuit I used with this(only the SD card interface is same) . Any body who interfaced SD card with str71X please help me.

[ This message was edited by: prasobhp on 03-05-2007 13:33 ]

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Attachments :

str-p711-sch.gif : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HtAr&d=%2Fa%2F0X0000000aJw%2FQ_n6K49veJZoSQFcFF01QYMQuVFLKnIQfu3gvc.G7DU&asPdf=false

ben2 · ‎2007-05-04

Posted on May 04, 2007 at 09:01

Hi,

Just a few points, I could be wrong, however this is how I am doing it.

Firstly the SS pin on my board is pulled high and I drive the SD card CS via a GPIO pin.

I believe, but could be wrong, that the CS must be high in the initial init phase to get the SD card into SPI mode. Once in SPI mode the CS must be low for the duration of the command and any returned data.

Also the clock speed during initialisation is between 100Khz to 400Khz.

With CS high you need to clock out all ones

Once into SPI mode, you can then up the clock as fast as you can go. That will depend on your system clock. The minimum divisor for the SPI clock is 6 on the STR710 devices.

Regards

Ben

prasobhp · ‎2007-05-04

Posted on May 05, 2007 at 03:16

Thanks ben_fnr for your help I will definitely try this one can you send me the circuit diagram you used ?

prasobhp · ‎2007-05-08

Posted on May 09, 2007 at 05:28

hi,

I did try my luck with what ben_fnr mentioned still I am not geting any response from SD card.

I reduced frequency to 400k&200K but still the result is same.Can anybody send me a working circuit of SD card interface.

prasobhp · ‎2007-05-10

Posted on May 11, 2007 at 05:15

hi all,

Thanks to your response I was able to write in to the card but I cant read from it since start of the frame token is not received.Same is the case for reading the registers also.Instead of start token(0xFE)I get 0xFC and all zeros after that.Expecting the same cooperation from your side

prasobh