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



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 :



mmc-> tran_speed = 2000000 ;


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

cat /sys/kernel/debug/mmc3/clock


Thanks & Best Regards,