using GPIO_16 pin as reference clock in RGMII

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using GPIO_16 pin as reference clock in RGMII

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JHY
Contributor IV


 

I found a below sentance

 

  "In RGMII Mode, only the pin "ENET_REF_CLK" could used as 125M reference clock input."

 

 

In RGMII Mode, I would like to use GPIO_16 pin as 125M reference clock input supplied from external device.

is it possible or impossible ?


 

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Yuri
NXP Employee
NXP Employee

GPIO_16 is intended for RMII reference clock; ENET_REF_CLK is intended for

RGMII reference clock. Next, ENET_REF_CLK is input clock, that is - an external

source should be applied. The problem  if internal clocks may be used for the

RGMII were discussed in community threads below, and as a resume :

"i.mx6 requires a Reference clock externally on ENET_REF_CLK pad and without

that it could not work / generate the TX CLK."

https://community.freescale.com/message/308970#308970

https://community.freescale.com/message/306197#306197

Have a great day,
Yuri

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Yuri
NXP Employee
NXP Employee

GPIO_16 is intended for RMII reference clock; ENET_REF_CLK is intended for

RGMII reference clock. Next, ENET_REF_CLK is input clock, that is - an external

source should be applied. The problem  if internal clocks may be used for the

RGMII were discussed in community threads below, and as a resume :

"i.mx6 requires a Reference clock externally on ENET_REF_CLK pad and without

that it could not work / generate the TX CLK."

https://community.freescale.com/message/308970#308970

https://community.freescale.com/message/306197#306197

Have a great day,
Yuri

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

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