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How to determine the Drive Strength Field values in u-boot for the custom hardware design ?

Question asked by Peter Amond on Jul 7, 2017
Latest reply on Jul 9, 2017 by Peter Amond

Hi All,


Here I'm referring to a custom hardware design related to imx6q processor and I have done the DDR calibration using stress test tool 2.6 version and using those calibrated values edited the following u-boot.imx files.





It is okay to edit read, write and DQS gating values according to the calibrations values. Then how should I determine the DSE values according to the my hardware design ?  (I mean following values)


DATA 4, MX6_IOM_DRAM_CAS, 0x00000030
DATA 4, MX6_IOM_DRAM_RAS, 0x00000030
DATA 4, MX6_IOM_GRP_ADDDS, 0x00000030

DATA 4, MX6_IOM_DRAM_RESET, 0x00000030
DATA 4, MX6_IOM_DRAM_SDBA2, 0x00000000
DATA 4, MX6_IOM_DRAM_SDODT0, 0x00000030
DATA 4, MX6_IOM_DRAM_SDODT1, 0x00000030
DATA 4, MX6_IOM_GRP_CTLDS, 0x00000030

DATA 4, MX6_IOM_DDRMODE_CTL, 0x00020000
DATA 4, MX6_IOM_DRAM_SDQS0, 0x00000028
DATA 4, MX6_IOM_DRAM_SDQS1, 0x00000028
DATA 4, MX6_IOM_DRAM_SDQS2, 0x00000028
DATA 4, MX6_IOM_DRAM_SDQS3, 0x00000028
DATA 4, MX6_IOM_DRAM_SDQS4, 0x00000028
DATA 4, MX6_IOM_DRAM_SDQS5, 0x00000028
DATA 4, MX6_IOM_DRAM_SDQS6, 0x00000028
DATA 4, MX6_IOM_DRAM_SDQS7, 0x00000028

DATA 4, MX6_IOM_GRP_DDRMODE, 0x00020000
DATA 4, MX6_IOM_GRP_B0DS, 0x00000028
DATA 4, MX6_IOM_GRP_B1DS, 0x00000028
DATA 4, MX6_IOM_GRP_B2DS, 0x00000028
DATA 4, MX6_IOM_GRP_B3DS, 0x00000028
DATA 4, MX6_IOM_GRP_B4DS, 0x00000028
DATA 4, MX6_IOM_GRP_B5DS, 0x00000028
DATA 4, MX6_IOM_GRP_B6DS, 0x00000028
DATA 4, MX6_IOM_GRP_B7DS, 0x00000028

DATA 4, MX6_IOM_DRAM_DQM0, 0x00000028
DATA 4, MX6_IOM_DRAM_DQM1, 0x00000028
DATA 4, MX6_IOM_DRAM_DQM2, 0x00000028
DATA 4, MX6_IOM_DRAM_DQM3, 0x00000028
DATA 4, MX6_IOM_DRAM_DQM4, 0x00000028
DATA 4, MX6_IOM_DRAM_DQM5, 0x00000028
DATA 4, MX6_IOM_DRAM_DQM6, 0x00000028
DATA 4, MX6_IOM_DRAM_DQM7, 0x00000028


Because when I run the stress test I could figure out some hardware errors and when I apply the values of the reference design(nitrogen6_max) for the above sections I could reduce the errors. So could you please tell me the affect of the above values for the stress test ? How can I figure out the correct DSE values for my design ? Is it like trial and error by changing many times determine the correct DSE value ?