About IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE_RGMII in i.MX6DQ.

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About IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE_RGMII in i.MX6DQ.

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keitanagashima
Senior Contributor I

Dear All,

Hello.

Refer to DDR_SEL in IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE_RGMII in IMX6DQRM(Rev.3).

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10 1P2V_IO— 1.2V I/O interfaces including USB HSIC and MIPI_HSI. Provides calibrated drive

strengths for signals ranging from 1.0V up to 1.3V.

11 1P5V_IO— 1.5V I/O interfaces including ENET. Provides calibrated drive strengths for signals

ranging from 1.3V to 2.5V.

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SABRE-SD uses the RGMII with 1.5V IO.

But, the register was set "10 1P2V_IO" in SABRE-SD with NXP Linux BSP (L3.14.28, L3.10.17, L3.0,35...).

On the other hand, there was below description in Hardware Design Guide.

Regardless of the voltage level, he ddr_sel of IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE_RGMII should always be set to ‘11’.

[Questions]

Q1. Is there any problem when selecting DDR_SEL=10(1.2V_IO) for 1.5V IO RGMII?

Q2. May we use as DDR_SEL=10(1.2V_IO) for final product?

Best Regards,

Keita

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Yuri
NXP Employee
NXP Employee

Hello,

  Basically DDR_SEL (say, in IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE_RGMII register)
is intended to adjust drive strength, which is mainly configured via the DSE field. This may
affect signal quality. Customers can try both cases (10: 1P2V_IO and 11: 1P5V_IO) to check

which is better.


Have a great day,
Yuri

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441 Views
Yuri
NXP Employee
NXP Employee

Hello,

  Basically DDR_SEL (say, in IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE_RGMII register)
is intended to adjust drive strength, which is mainly configured via the DSE field. This may
affect signal quality. Customers can try both cases (10: 1P2V_IO and 11: 1P5V_IO) to check

which is better.


Have a great day,
Yuri

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

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