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MPC8315E - PCIe interface

Question asked by Ane Irazusta on May 7, 2019
Latest reply on May 7, 2019 by Bulat Karymov

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Hello,

I was wondering how I should disable/enable the SerDes PCIe interface of the MPC8315E via SW. Would be enough to configure SDPD bit of SRDSCR0 register to '1' (Block power down) for disable it?

And should I also make any change in HW? For example, following the application note AN3438, it says that SD_IMP_CAL_TX signal has to be connected to GND using a 100R precision resistor when the interface is used, but when not used it has to be connected to 1V. If I disable the PCIe interface via SW, can SD_IMP_CAL_TX signal still be connected to the 100R resistor?

Thanks in advance!

Regards,

Ane

Bulat Karymov

May 7, 2019 6:45 PM

Correct Answer

I believe it will be ok. Side effect is that grounded resistors could cause additional unnecessary power consumption.

Regards,

Bulat

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Bulat Karymov

May 7, 2019 4:12 AM

Yes, setting of SRDSCR0[24] bit is enough for powering down (disabling) entire SERDES from SW point of view.

Yes, if SERDES is not used, you can connect both SD_IMP_CAL_TX (and SD_IMP_CAL_RX) to 1V via 100 Ohm resistors.

Regards,

Bulat

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Ane Irazusta @ Bulat Karymov on May 7, 2019 5:13 AM

Thank you for answering Bulat!

And would it be ok if I leave both calibration signals connected to GND via 100 Ohm (or 200 Ohm) resistor when I power down the SERDES?

Regards,

Ane

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Bulat Karymov

@ Ane Irazusta on May 7, 2019 6:45 PM

I believe it will be ok. Side effect is that grounded resistors could cause additional unnecessary power consumption.

Regards,

Bulat

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Bulat Karymov May 7, 2019 4:12 AM
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Yes, setting of SRDSCR0[24] bit is enough for powering down (disabling) entire SERDES from SW point of view.
Yes, if SERDES is not used, you can connect both SD_IMP_CAL_TX (and SD_IMP_CAL_RX) to 1V via 100 Ohm resistors.

Regards,
Bulat
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- Ane Irazusta @ Bulat Karymov on May 7, 2019 5:13 AM
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  Thank you for answering Bulat!
  
  And would it be ok if I leave both calibration signals connected to GND via 100 Ohm (or 200 Ohm) resistor when I power down the SERDES?
  
  Regards,
  Ane
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  - Bulat Karymov @ Ane Irazusta on May 7, 2019 6:45 PM
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    Correct Answer
    I believe it will be ok. Side effect is that grounded resistors could cause additional unnecessary power consumption.
    
    Regards,
    Bulat
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MPC8315E - PCIe interface

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