topic Re: Issues About LPDDR4 on iMX8 Frequency setting in i.MX Processors

Issues About LPDDR4 on iMX8 Frequency setting

shangregister — Tue, 10 Sep 2019 09:41:44 GMT

Hi All,

Help!

I downloaded the Msacle Tools for mx8m EVB and i saw the setting about the LPDDR4 Freq is 1600Mhz.

i see the default setting in RPA excel had a value is :1600,800,334,200Mhz.

and i find the Formula in RPA below:

# Formula is DDR_freq = [REF/DIVR1*2*DIVF1/DIVR2*DIVF2*2/2/DIVQ] x 2

so how can i set the freq to another value : e.g.1333,1200Mhz??

and what is the meaning in Formula variable (REF,DIVR1,DIVQ........) any doc can find??

HansonD

Re: Issues About LPDDR4 on iMX8 Frequency setting

igorpadykov — Wed, 11 Sep 2019 00:04:58 GMT

Hi Hanson

I am afraid there is no additional documentation for usage RPA excel tool.

In general for additional info one can check documentation included in

i.MX8 MSCALE SERIES DDR Tool Release (V2.10)

and linux documentation, sect.2.5.4 Dynamic Bus Frequency

Linux L4.14.98_2.0.0 Documentation

Best regards
igor
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Re: Issues About LPDDR4 on iMX8 Frequency setting

shangregister — Wed, 11 Sep 2019 01:17:52 GMT

hi igor

Thank!

i find some detail "ini.MX 8M Dual/8M QuadLite/8M Quad
Applications Processors Reference
Manual" about HW_DRAM_PLL_CFG2_ADDR with that Formula .

and one more is

when i using the DDR tools to gen code for uboot.

Is it actually follow the uboot setting in linux kernel run??

because i seen some soc uboot ddr freq and kernel freq is difference.

is it need to modify u-boot and kernel for linux?

if yes, where is the kernel setting file?

Best regards

Hanson

Re: Issues About LPDDR4 on iMX8 Frequency setting

igorpadykov — Wed, 11 Sep 2019 07:33:14 GMT

Hi Hanson

please check comments on below link describing how change ddr frequency:

i.MX8 MSCALE SERIES DDR Tool Release (V2.10)

Best regards
igor