am335x sd card can not boot

Hi,

To which AM335X pins is your SD card connected? What are your SYSBOOT pin settings?

Thank you for your replies.

SDcard pins        cpu pins

  D0      ---------------G16(MMC0_DATA0)

   D1     ---------------G15(MMC0_DATA1)

  D2      ---------------F18(MMC0_DATA2)

 D3       ---------------F17(MMC0_DATA3)

  CMD  ---------------G18(MMC0_CMD)

  CLK  ---------------G17(MMC0_CLK)

   CD    -------------  A16(SPI0_CS0)

SYSBOOT settings:

AM335X_LCD_DATA[15.0]   0100XXXXXXXX110111b  MMC0, SPI0, UART0, USB0

By the way, I am not every time boot failed ,just occasionally.

The pins are correct. The Card Detect signal is on a different pin, but this should not prevent booting. There must be some signal integrity issue on your board if this happens occasionally. Do you have external pullups  on DATA and CMD lines, and a serial resistor on the CLK line?

Thank you for your replies.

Yes, I do. The DATA CMD CD lines have pullups of 10Kohm, and also clk line has a serial resistor close to cpu.

If you will, I can email to you my sch and pcb and please help me to check.

Thank you.

Best Regards,

Liu

Have you tried if this happens with other cards?

No,I have only sandisk cards. But I have tested different capacity(4GB 8GB 16GB) and  got the same results.

Dose TI have the reports about sdcard's compatibility for am335x?

Would you please give me your email address? I can send my sch and pcb to you and please help me to analyze

if there are some signal integrity issue on my board.

My email address is liusq1980@163.com.

Thank you very much.

Best Regards

liu

There is no such report.

If you require a schematic/layout review you will have to contact your nearest TI representative. We cannot accept review requests through the forum.

Thank you ,Biser.

I resolve my problem. And another question:  I want change my tf socket(push push type now) to hinge type.

But the hinge type tf card there is not CD pin that connected to CPU's AM335X_SPI0_CS1.

My question is CD pin is necessary for AM335x?

if it's not necessary,need I to change uboot linux source code to fit it ?

My hinge type tf card socket is MOLEX's 0472192001(part number).

Thank you very much.

Best Regards,

liu

If you don't have anything else attached to AM335X_SPI0_CS1 you can simply turn on the internal pulldown on this pin and it will emulate CD. Otherwise you may need to find where it's polled in the MMC driver and modify it, but I'm not a Linux expert and cannot give you precise directions how to do it. What I do know is that it's polled as a GPIO.

Ok, I see.

Thank you very much.

Best Regards,

Liu

If I remember correctly, the Beagebones do not use the CD pin and they work fine.

You probably have to change your kernel. If you are using a 3.2 kernel, you modify arch/arm/mach-omap2/board-am335xevm.c and change the gpio used to -EINVAL. If you are using a 3.12 kernel I think you would modify arch/arm/boot/dts/am335x-bone-common.c, but I'm not sure.

Steve K.