how to modify HS400 or HS200 at imx-iotcore driver usdhc in Windows 10 IOT Core on IMX8mq evk

[tom_shen]

Hello Experts,

    I want to modify HS400 or HS200 eMMC speed at imx-iotcore driver usdhc in Windows 10 IOT Core on IMX8mq evk, but I can’t modify it correctly. Can you tell me how to modify it?

By the way,

Is it that the eMMC bus width cannot be automatically judged and always used 8 bits bus width?

thanks

[igorpadykov]

Hi Shen

emms driver performs HS400 or HS200 selection automatically, no code modification is needed.

Procedure is described in emmc JESD84-B50 specification  https://www.jedec.org/sites/default/files/docs/JESD84-B50.pdf

In HS400 mode only 8-bit bus width is supported.  Bus width is defined by Extend CSD register

BUS_WIDTH [183]. It is set to ‘0’ (1 bit data bus) after power up and can be changed by a SWITCH command. After host initializes the emmc device, it verify that the device supports the HS200/400

mode by reading the DEVICE_TYPE field in the Extended CSD register.

Best regards
igor

[tom_shen]

Hi igorpadykov

I agree that emmc driver performs HS400 or HS200 selection automatically for the linux driver,
but the driver in the Windows iot core does not seem to be HS400 or HS200 selection automaticallyat least from the existing code base (from W1809_1_1_0_imx-iotcore.zip)

imx-iotcore\driver\sd\imxusdhc\usdhc.cpp

Could you suggest how to modify it in windows10 IoT core? (because I modify capabilitiesPtr->Supported.HS200 = 1 and capabilitiesPtr->Supported.HS400 = 1, this modification would result in fail to boot up)

thanks

[igorpadykov]

one can look at linux driver described in sect.3.3 MMC/SD/SDIO Host  i.MX Linux Reference Manual​

and try to port it.

Best regards
igor

[tom_shen]

Will NXP still release a new version of BSP and firmeware source code for Win10 IoT core?

https://www.nxp.com/design/software/embedded-software/i-mx-software/windows-10-iot-core-for-i-mx-app...

[igorpadykov]

for future release plans please apply to local marketing office.

Best regards
igor