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PCIe Enumeration of C6678L after Linux host boot.

Hi,

We're working on a project involving a C6678L connected to a linux Host over PCIe.

We would like to be able to power the DSP independatntly of the Linux Host, so that we can bring the DSP up while the host is already fully booted, use it, and then power it down while the host is still running.

currently the DSP will only enumerate on the Linux host if it is powered up first.

We are testing using a linux workstation and a TMDXEVM6678L.

Is it possible to bring the host up first then power up and enumerate the DSP later?

Regards,

Steve

3 Replies

  • Steve,

    I assume you used a AMC to PCIE adaptor card to plug the 6678L EVM into a PCIE slot of the Linux workstation. In this case, the DSP gets the power supply from PCIE slot of workstation. How do you "so that we can bring the DSP up while the host is already fully booted, use it, and then power it down while the host is still running"?

    Also, the PCIE enumeration process only happened when Host is booting up. If the Linux machine is always powered on, and you have a way to seperatedly power on/off the DSP card, the PCIE will not get enumerated.

    Why you want to power cycle DSP after enumeration? you want to do some reset?

    Regards, Eric

     

     

  • In reply to lding:

    Eric,

    We are powing the DSP card from an external supply.

    Our main goal is to save as much power as possible when we don't need to use the DSP, It could be that we don't use the DSP at all for a long stretch of time but then need to have it up and running again at short notice (a few seconds). Ideally we would turn the DSP off between these events and so have it draw no power at all.

    If it is not possible to power down the card without breaking the PCIE connection, could we send it into a deep sleep of some form without breaking the PCIE?

    Regards,

    Steve

  • In reply to Steve Tickle:

    Steve,

    You can check PSC user guide http://www.ti.com/litv/pdf/sprugv4b to turn off some power domain and clock domain modules unused (PCIE module always ON).

    Regards, Eric