AnsweredAssumed Answered

Change freqency of mmc on imx6dl

Question asked by Pham Van Dong on Aug 10, 2017
Latest reply on Aug 18, 2017 by Pham Van Dong

Hi,

 


I am using IMX6DL and linux kernel 4.1.15 , uboot 2015.04.

I understand that imx6 support eMMC 4.x with HS200 and default speed of mmc is 52Mhz.

 

I have 2 questions :

- How can I know that eMMC is working with SDR or DDR?

- How can we change speed of mmc for eMMC? which speeds will it support?

Can we set clock of mmc < 26Mhz ? I want to reduce it for EMC product testing.

 

In Uboot, I tried to change speed to difference value as below :

drivers/mmc/mmc.c

.........

mmc-> tran_speed = 2000000 ;

 

but after boot, I alway got 52Mhz from command :

cat /sys/kernel/debug/mmc3/clock
52000000

 

Thanks & Best Regards,

Dong

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