We use i.mx6ull.
There is a description that "memory arrays domain voltage level should be kept equal to the rest of the core logic domains (Main, ARM)" in reference manual.
1. Does this description mean VDD_ARM_CAP and VDD_SOC_CAP should be equal ?
Reference manual p.366
Reference manual p.377
2. The typical value of VDD_ARM_CAP is 1.275. Is the typical value of VDD_SOC_CAP 1.275 too?
datasheet p.24
There is a regulation for the set voltage difference between VDD_SOC_IN and VDD_ARM_CAP (according to the following selected description), but there is no regulation for the voltage difference between VDD_ARM_CAP and VDD_SOC_CAP.
datasheet p.24
3. Is there a regulation for the allowable voltage difference between VDD_ARM_CAP and VDD_SOC_CAP?
We think that if 1. is correct, following set value is not correct.
(e.g. The difference between VDD_ARM_CAP and VDD_SOC_CAP at 900MHz is 25000uV. not 0uV)
4. Would you tell me what is correct ?
imx6ull.dtsi
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 1250000 792000 1175000 528000 1175000 396000 1175000 198000 1175000 >;
https://github.com/varigit/linux-imx/commit/c3e4be705852c6d973d3b1f2b8b024fdea7303af
Would you answer 1. to 4. ?
Reference:
- Datasheet: "i.MX 6ULL Applications Processors for Consumer Products (REV 1.3)"
- Reference Manual: "i.MX 6ULL Applications Processor Reference Manual (REV 1) "
https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/i-mx-applications-proces...
This question is related to https://community.nxp.com/t5/i-MX-Processors/What-will-occur-when-setting-i-mx6ull-VDD-SOC-CAP-at-90...
Best regards
Solved! Go to Solution.
Hi shaot
> 1. Does this description mean VDD_ARM_CAP and VDD_SOC_CAP should be equal ?
no.
That description is general description for arm power distribution system. i.MX6ULL has
not "ARM Memory array" subsystem.
>2. The typical value of VDD_ARM_CAP is 1.275. Is the typical value of VDD_SOC_CAP 1.275 too?
not.
Please refer to imx6ull.dtsi file it shows typical values.
>3. Is there a regulation for the allowable voltage difference between VDD_ARM_CAP and VDD_SOC_CAP?
no
>4. Would you tell me what is correct ? [..We think that if 1. is correct, following set value is not correct...]
a) referenced "imx6ull.dtsi" is correct
b) "1." is incorrect.
Best regards
igor
Hi shaot
> 1. Does this description mean VDD_ARM_CAP and VDD_SOC_CAP should be equal ?
no.
That description is general description for arm power distribution system. i.MX6ULL has
not "ARM Memory array" subsystem.
>2. The typical value of VDD_ARM_CAP is 1.275. Is the typical value of VDD_SOC_CAP 1.275 too?
not.
Please refer to imx6ull.dtsi file it shows typical values.
>3. Is there a regulation for the allowable voltage difference between VDD_ARM_CAP and VDD_SOC_CAP?
no
>4. Would you tell me what is correct ? [..We think that if 1. is correct, following set value is not correct...]
a) referenced "imx6ull.dtsi" is correct
b) "1." is incorrect.
Best regards
igor
Thank you.
About the sentence "memory arrays domain voltage level should be kept equal to the rest of the core logic domains (Main, ARM)".
Would you tell me what voltage should be equal in Power Tree (Refrence manual p.360)?
>what voltage should be equal in Power Tree (Refrence manual p.360)?
there are no such voltages, according to Table 10. Operating Ranges
i.MX 6ULL Applications Processors for Consumer Products
Reference Manual gives just generic desription, one needs to
follow particular datasheet description which prevails over Reference Manual.
Best regards
igor
Thank you for the information.