Hi, I use i.mx6ull and Yocto Morty.
Actually I noticed that fsl,soc-operating-points (VDD_SOC_CAP) is 1.175V at 900MHz in my device tree.
(refer to https://github.com/varigit/linux-imx/commit/c27010d99a3d91703ea2d1a3f9630a9dedc3f86f)
my device tree
cpu0: cpu@0 { compatible = "arm,cortex-a7"; device_type = "cpu"; reg = <0>; clock-latency = <61036>; /* two CLK32 periods */ operating-points = < /* kHz uV */ 900000 1275000 792000 1225000 528000 1175000 396000 1025000 198000 950000 >; fsl,soc-operating-points = < /* KHz uV */ 900000 1175000 792000 1175000 528000 1175000 396000 1175000 198000 1175000 >;
datasheet (old)
(See attached i.mx6ull_datasheet_old.png)
However I found that fsl,soc-operating-points (VDD_SOC_CAP) should be 1.25V because 1.175V is old datasheet value and was updated in the latest kernel. (refer to https://github.com/varigit/linux-imx/commit/c3e4be705852c6d973d3b1f2b8b024fdea7303af)
dts (should be updated to this)
fsl,soc-operating-points = < /* KHz uV */ 900000 1250000 792000 1175000 528000 1175000 396000 1175000 198000 1175000 >;
new datasheet
(See attached i.mx6ull_datasheet_new.png)
https://www.nxp.com/docs/en/data-sheet/IMX6ULLCEC.pdf
history
(See attached history.png)
It seems that VDD_SOC_CAP is for L1/L2 caches voltage.
(See attached vdd_soc_cap.png)
In my understanding, read/write from ROM/RAM will sometimes fail depending on a board.
However the circuit is not open and I am not sure what will occur.
What will occur if I set VDD_SOC_CAP 1.175V at 900MHz and why?
Why did you update the voltage at 900MHz?
Best regards,
解決済! 解決策の投稿を見る。
Hi shaot
>What will occur when setting i.mx6ull VDD_SOC_CAP at 900MHz 1.175V (Old datasheet value)?
this may lead to upredictable processor behaviour, exceptions or hanging. Datasheet was updated after
more factory testing and new datasheet parameters should be followed.
Best regards
igor
Hi shaot
>What will occur when setting i.mx6ull VDD_SOC_CAP at 900MHz 1.175V (Old datasheet value)?
this may lead to upredictable processor behaviour, exceptions or hanging. Datasheet was updated after
more factory testing and new datasheet parameters should be followed.
Best regards
igor
Thank you! I am sorry for late reply.