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Power domain, PCIe c6678

Delared Delared
Expert 1945 points

Hi,

In C:\Program Files\Texas Instruments\pdk_C6678_1_0_0_17\packages\ti\drv\pcie\example\sample, a function is used to introduce delay (line 137, 165)!

cycleDelay(10000);

1-      Its main role is to insure stabilization of power and clock before beginning, right???

2-      The count value is always 10 000 or I can change it ??

  • 0
    TI__Intellectual 2180 points

    The cycleDelay() function waits that number of core cycles (which are approximately ns).  This this is a 10us sleep.

    It comes from: L lock. "Driven high asynchronously between 2048-3071 refclkp/n cycles after the PLL has locked".

    Instead, one could poll the LOCK bit of PCIE_SERDES_STS.

  • 0 in reply to John Dowdal
    Expert 1945 points

    Dowdal,

    In PCIe userguide I found: “The LOCK bit of PCIE_SERDES_STS register will be driven high by the digital lock detector. We can sample this bit during the PLL initialization to indicate the refclkp/n are stable”.

    So we can simply test The LOCK bit of PCIE_SERDES_STS! I’ll have always the same result???  However, what is the solution more performed???

    Also i have a question about : CSL_BootCfgUnlockKicker() and CSL_BootCfgLockKicker() in line 155 and 162.

    it is mentionned that are used to Lock/unlock the kicker mechanism!!  what does it mean??? I need more explanations please..


  • 0 in reply to Delared Delared
    TI__Intellectual 2180 points

    Delared Delared said:
    So we can simply test The LOCK bit of PCIE_SERDES_STS! I’ll have always the same result???

    Yes, except it could exit after a variable amount of time, but the PLL will always be locked (else it will wait forever).

    Delared Delared said:
     However, what is the solution more performed???

    I don't understand the question.

    Delared Delared said:

    Also i have a question about : CSL_BootCfgUnlockKicker() and CSL_BootCfgLockKicker() in line 155 and 162.

    it is mentionned that are used to Lock/unlock the kicker mechanism!!  what does it mean??? I need more explanations please..

    Usage note 4 in http://www.ti.com/lit/er/sprz334e/sprz334e.pdf indicates that you should not use the kicker.  You should just unlock it once and leave it unlocked.  The example is single core (so the multicore issue doesn't apply) and predates the usage note.