ZQ Calibration of i.MX6

[宗標廖]

Hello Community

In page 11 of AN4467(i.MX 6 Series DDR Calibration) , there is description  as bellow.

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ZQ calibration is a process that tunes the DRAM and MMDC I/O Pad output drivers (drive strength) and
ODT values across changes in process, voltage, and temperature.

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After ZQ calibration, we can read ZQ_HW_PD_RES and ZQ_HW_PU_RES fields of the MPZQHWCTRL register.

How does ZQ_HW_PD_RES and ZQ_HW_PU_RES relate to DSE field of IOMUX control register and DDR ODT?

That is how should I set DSE filed and MMDC_MPODTCTRL register according to the ZQ result.

Thank you!

ZongbiaoLiao

[igorpadykov]

Hi ZongbiaoLiao

unfortunately this is misprint, calibration process

does not tweak and relate to DSE field of IOMUX control register.

Best regards
igor
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[宗標廖]

Hi, igor 

Thank you for you reply!

How to use ZQ_HW_PD_RES and ZQ_HW_PU_RES after ZQ calibration finished.

Thank you!

[igorpadykov]

Hi ZongbiaoLiao

please check sect.44.11.2.1.1 ZQ automatic Pull-up calibration,
44.11.2.1.2 ZQ automatic Pull-down calibration
i.MX6DQ Reference Manual
http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6DQRM.pdf

Best regards
igor

[宗標廖]

Hi igor

Please help me!

Thanks.

[igorpadykov]

Hi ZongbiaoLiao

please check sect.44.12.32 MMDC PHY ZQ SW control register (MMDCx_MPZQSWCTRL) :

MMDCx_MPZQSWCTRL[USE_ZQ_SW_VAL ] - this bit selects whether ZQ SW value or ZQ
HW value will be driven to the I/O pads resistor controls.

Best regards
igor

[宗標廖]

Hi Igor

ZQ automatic Pull-up calibration and ZQ automatic Pull-down calibration are just the two parts of ZQ calibration.

After ZQ calibration finished, who should refer to the results(ZQ_HW_PD_RES and ZQ_HW_PU_RES)?

Thank you!