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standalone SD card SDIO

Former Member

Hello,

I try to use the SD card of the Zedboard via the SDIO port. I use chans FatFs. First I implemented the diskio.c by my own, but then debugging it I found that there is an implementation in an example project, so now I use that one.
It can be found here:
XilinxSDK2014.2dataembeddedswlibsw_servicesxilffs_v2_1


Initialization works partly, but not fully:
.

XSdPs_SdCardInitialize
XSdPs_Change_ClkFreq(&SdInstance, SD_CLK_25_MHZ);
and XSdPs_Select_Card
.

work propperly, but XSdPs_Get_BusWidth does not anymore.
It seems like commands are accepted, but DMA transfers are not:
.
/*
* Send block write command
*/
Status = XSdPs_CmdTransfer(InstancePtr, CMD55,
tttInstancePtr->RelCardAddr, 0);
tif (Status != XST_SUCCESS) {
t....Status = XST_FAILURE;
t....goto RETURN_PATH;
t}

tBlkCnt = XSDPS_SCR_BLKCNT;
tBlkSize = XSDPS_SCR_BLKSIZE;

t/*
t * Set block size to the value passed
t */
tBlkSize &= XSDPS_BLK_SIZE_MASK;
tXSdPs_WriteReg16(InstancePtr->Config.BaseAddress,
tttXSDPS_BLK_SIZE_OFFSET, BlkSize);

tXSdPs_SetupADMA2DescTbl(InstancePtr, BlkCnt, SCR);

tXSdPs_WriteReg16(InstancePtr->Config.BaseAddress,
tttXSDPS_XFER_MODE_OFFSET,
tttXSDPS_TM_DAT_DIR_SEL_MASK | XSDPS_TM_DMA_EN_MASK);

tStatus = XSdPs_CmdTransfer(InstancePtr, ACMD51, 0, BlkCnt);
tif (Status != XST_SUCCESS) {
t....Status = XST_FAILURE;
t....goto RETURN_PATH;
t}
.
SdPs_CmdTransfer(InstancePtr, ACMD51, 0, BlkCnt) returns with 1.
.

Maybe I did something wrong in the hardware design. I added the SD 0 Peripheral and assigned CD to MIO 47, WP to MIO46.
Do I have to activate the DMA somehow?
.
There is one funny fact: when I let the example program run, a file is generated on the SD, but it cannot be neither read nor written by the zynq.
.
Best regards,
Yaro

Parents Reply
  • 0 in reply to Former Member

    Hi,
       Thanks for your help, I have tested your code on Microzed and Zedboard, here is what I found.
    1.10 SD cards from 4 different vendors(Sandisk, Lexar,ATP,Delkin), 7 of 10 passed the test, 3 failed with empty file.
    2. I have verified the card itself is good.
    3. 2 failed cards (ATP Brand),I can boot from them (read file is ok), the 3rd failed one(Lexar brand) , I even couldn't boot from it.

    Please share your experience if you have same issue.

    Thanks

Children
  • 0 in reply to Former Member

    Hello,

    make first sure, that the cards are formatted with fat32.
    SD-Cards are in general pretty moody, so a lot of things might cause the problem.
    Regarding the caches, please first make sure that your file buffers are 32-aligned.

    Maybe try to uncomment (in diskio.c)
    Status = XSdPs_Pullup(&SdInstance);
    tif (Status != XST_SUCCESS) {
    tts |= STA_NOINIT;
    ttreturn s;
    t}

    tif (SCR[1] & WIDTH_4_BIT_SUPPORT) {
    ttStatus = XSdPs_Change_BusWidth(&SdInstance);
    ttif (Status != XST_SUCCESS) {
    ttts |= STA_NOINIT;
    tttreturn s;
    tt}
    t}

    and

    if (SCR[1] & WIDTH_4_BIT_SUPPORT) {
    ttStatus = XSdPs_Change_BusWidth(&SdInstance);
    ttif (Status != XST_SUCCESS) {
    ttts |= STA_NOINIT;
    tttreturn s;
    tt}
    t}

    maybe even
    Status = XSdPs_Change_ClkFreq(&SdInstance, SD_CLK_25_MHZ);
    tif (Status != XST_SUCCESS) {
    tts |= STA_NOINIT;
    ttreturn s;
    t}

    Doing the experiments, do not boot from the sd-card, but from JTAG to avoit problems.
    Before every test, power-cycle the board (leave it off for >4 seconds).

    To figure out, whether this is a Xilinx driver problem or a lirary problem, one could use a bitbanging low level driver available at http://elm-chan.org/fsw/ff/00index_e.html with a customization to Zynqs GPIO.

  • 0 in reply to Former Member

    Hi Yaro123,

    Thanks a lot for sharing your Project. However I am unable to open up the zynq IP as it seems to be one version higher up and i'm still using 2014.2. (There's other concerns that I'll have to deal with if I upgrade).

    Can you answer a couple of questions.

    1) What was the clock frequency provided to the SD card? I understand that this goes through pin E14, however don't really know if it takes FCLK0.

    2) What is the max frequency that I can clock the SD card at with this specific bundle of example application?

    Thanks again for sharing this.

  • 0 in reply to Former Member

    Hi Yaro123,

    Thanks a lot for sharing your Project. However I am unable to open up the zynq IP as it seems to be one version higher up and i'm still using 2014.2. (There's other concerns that I'll have to deal with if I upgrade).

    Can you answer a couple of questions.

    1) What was the clock frequency provided to the SD card? I understand that this goes through pin E14, however don't really know if it takes FCLK0.

    2) What is the max frequency that I can clock the SD card at with this specific bundle of example application?

    Thanks again for sharing this.

  • 0 in reply to Former Member

    Hi Yaro,

    I realize this is quite some time after your post.

    Can you tell me how I find out what frequency the SD card is clocked at? Unfortunately I cannot open up your project as it is a later version of the IP. Also cannot upgrade for other reasons.

    I'm trying to figure out what is the fastest data rite speed I can get with that example project.

    Omkar

  • 0 in reply to Former Member

    Hi guys, we are trying to implement a way to read/write to an sd card using vivado system and a Zedboard. We are very noob about the argument. Can you give us an hand (send us some example and basic code) ?
    Thanks in advance for the help