i.MX7D USDHC BOOT/VSELECT and Ethernet2/ELCDIF Pin questions

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i.MX7D USDHC BOOT/VSELECT and Ethernet2/ELCDIF Pin questions

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demoniacmilk
Contributor IV

Hello all,

I am planning to use all 3 uSDHC interfaces for a new i.MX7D Design.

They will be used for: eMMC, WiFi Module, SD Card.

Is there a possible setup that allows booting from SD card if inserted and from eMMC else? (Without additional ICs) Maybe this could be done in uboot?

Also, what is the purpose of the VSELECT pin? Would it be used to control e.g. the PF3000 PMIC VCC_SD Pin? Is it only used as a flag? What may happen if i decide to ignore this pin?

Having the 24 Bit LCD Interface and double ethernet available would be awesome as well.
Unfortunately, LCD_RD_E and RGMII_TX_CTL are muxed to the same pin, with no alternatives. TX_CTL is used in RMII and RGMII modes, so there is no way to not use it. Is it impossible to use both at the same time? I have found an MX7 Module that provides 2x Gigabit Ethernet and the LCD interface, it uses a DSI<->LVDS converter

Regards,
Lars

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igorpadykov
NXP TechSupport
NXP TechSupport

Hi Lars

VSELECT is described in sect.10.3.8.28 Vendor Specific Register (uSDHCx_VEND_SPEC)

i.MX7D Reference Manual

http://cache.nxp.com/files/32bit/doc/ref_manual/IMX7DRM.pdf

"Change the value of output signal VSELECT, to control the voltage on pads for external card. There must
be a control circuit out of uSDHC to change the voltage on pads."

Example of usage can be found in i.MX7D Sabre SD schematic, using pmic SD_VSEL:

"Input from i.MX processor to select VCC_SD regulator voltage",

described in pmic datasheet

https://www.nxp.com/docs/en/data-sheet/PF3000.pdf 

>Is there a possible setup that allows booting from SD card if inserted and from eMMC else? 

please check sect.6.6.12 SD/MMC Manufacture Mode i.MX7D Reference Manual

http://cache.nxp.com/files/32bit/doc/ref_manual/IMX7DRM.pdf

For checking feasibility both LCD Interface and double ethernet one can use Pin Tool:

Pins Tool for i.MX Application Processors|NXP 

Best regards
igor
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igorpadykov
NXP TechSupport
NXP TechSupport

Hi Lars

VSELECT is described in sect.10.3.8.28 Vendor Specific Register (uSDHCx_VEND_SPEC)

i.MX7D Reference Manual

http://cache.nxp.com/files/32bit/doc/ref_manual/IMX7DRM.pdf

"Change the value of output signal VSELECT, to control the voltage on pads for external card. There must
be a control circuit out of uSDHC to change the voltage on pads."

Example of usage can be found in i.MX7D Sabre SD schematic, using pmic SD_VSEL:

"Input from i.MX processor to select VCC_SD regulator voltage",

described in pmic datasheet

https://www.nxp.com/docs/en/data-sheet/PF3000.pdf 

>Is there a possible setup that allows booting from SD card if inserted and from eMMC else? 

please check sect.6.6.12 SD/MMC Manufacture Mode i.MX7D Reference Manual

http://cache.nxp.com/files/32bit/doc/ref_manual/IMX7DRM.pdf

For checking feasibility both LCD Interface and double ethernet one can use Pin Tool:

Pins Tool for i.MX Application Processors|NXP 

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

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