Failed to boot i.mx6ul from usdhc2

[dhvanil_patel1]

Hi,

We are developing produce based on i.MX6UL. We are facing an issue while booting the board from uSDHC2 port. We are using below mention pinmux for uSCHD2. We have set the boot config register to boot device from uSDHC2 port along with boot mode setting to internal boot. When we power up the device, The i.MX6UL Boot ROM is not generate any clock on usdhc2.CLK (LCD_DATA19) pin to boot from uSDHC2

#	Name	Default	ALT0	ALT8
A13	LCD_DATA18	gpio3.IO[23]	lcdif.DATA[18]	usdhc2.CMD
D14	LCD_DATA19	gpio3.IO[24]	lcdif.DATA[19]	usdhc2.CLK
C14	LCD_DATA20	gpio3.IO[25]	lcdif.DATA[20]	usdhc2.DATA0
B14	LCD_DATA21	gpio3.IO[26]	lcdif.DATA[21]	usdhc2.DATA1
A14	LCD_DATA22	gpio3.IO[27]	lcdif.DATA[22]	usdhc2.DATA2
B16	LCD_DATA23	gpio3.IO[28]	lcdif.DATA[23]	usdhc2.DATA3

During debugging, we found,The i.MX6UL boot ROM generates clock on "NAND_RE_B" pin.

Is there any way available to  set Boot ROM to generate CLK on "usdhc2.CLK (LCD_DATA19)"  and boot from uSDHC2 port with above mentioned pin settings?

-

Dhvanil Patel

[igorpadykov]

one can first boot from spi-nor or other media, then from uSDHC2 port.

Similar approach is given in attached AN4691.

~igor

[durmus]

Hi,

From reference manual section 8.5.3.4 IOMUX Configuration for SD/MMC;

It seems that for USDHC boot you can only use specific pads and not other alternatives.

For your case, booting from USDHC2 seems to be only supported through NAND_... pads.