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OMAP-L138 & Phy

ranchu
Guru 20755 points

Other Parts Discussed in Thread: OMAP-L138

Hello, In my custom board the Phy is connected to the OMAP-L138 processor through "enable switch", i.e. I can enable disbale the Phy by changing a known GPIO output in the OMAP. I see starnge thing: when I disable the Phy the OMAP, reset itself, as if It cannot work without Phy. I see it not only in u-boot, but also when configuring the OMAP in the CCS with the GEL file. Does the OMAP cannot work without Phy ? Best Regards, Ran
  • 0
    TI__Genius 14545 points

    Ran,

       Why PHY are you referring to? EMAC?

      The OMAP-L138 can work with various peripherals disabled.

     

  • 0 in reply to dabuan
    Guru 20755 points

    Hi Drew,

    I am refering to EMAC. if the peripheral is not disabled (while the component is missing or does not function), will it result in unexpected behaviour?I ask the question becuase it seems as if the OMAP reset itself, when I disable the Phy component(without disbaling the controllerin the OMAP). Same thing happens with the Serial controller too.

    Thank you for your time,

    Ran

  • 0 in reply to dabuan
    Guru 20755 points

     

    Hi Drew,

    I refer to RMII ETHERNET PHY.

    Is is possible that in case the Phy component is missing, the OMAP will reboot itself (or get into other unexpected behaviour) ? As I said I see the same thing happend also in the CCS , immediately after "turning off" the component (I am able to do it using GPIO from the OMAP). I suspect that maybe I have to disable the controller (LPSC) in order to prevent this behaviour, but still it seems strange that the OMAP will act this way becuase of external PHY.

    Ran

  • 0 in reply to ranchu
    TI__Genius 14545 points

    Ran,

       From a strictly silicon point of view,  don't know of a reason why the OMAP-L138 cannot run fine without the EMAC.

    What is your hardware platform? What software package (if any) are you running on the OMAP-L138.

    I think it would be worth while to look into the settings of the Interrupt Controllers to both the ARM  and the C674x DSP to see if there are any EMAC events that are kicking off some reboot sequence.

  • 0 in reply to dabuan
    Guru 20755 points
    Hi Drew, I am using PSP 3.20.00.11, and custom board with OMAP-L138 , and SMSC RMII LAN 8F20A. The Phy is connected to the OMAP with GPIO8_11 used as output for the Phy Power. OMAP Phy GP8_11 -------> Power Pin PHY_PINS Phy Pins I have checked the interrupts, but and it seems that all interrupts are disabled (in u-boot & when using OMAP-L138 EVM GEL file of LogicPD). Also when The PSC of EMAC is disabled the same GP8_11 on/off makes the CCS lose connection and the OMAP reboots itself. It is hard to know what comes first: Is it really interrupt that cause the reboot, or maybe power consumption of the Phy component, which maybe is causing a kind of power consumption problem to the OMAP. Also interesting to NOTE that in the GEL file, the EMAC pinmux is not set at all (there is not such script actually). Anyway, I Still didn't find where is the problem... Best Regards, Ran
  • 0 in reply to ranchu
    TI__Genius 14545 points

    Ran

    ran shalit said:
    The Phy is connected to the OMAP with GPIO8_11 used as output for the Phy Power. OMAP Phy GP8_11 -------> Power Pin

    Are you using GPIO8_11 to supply power to the EVM PHY? If so, this cannot be done. If not, can you please clarify your connections, possibly with a block diagram?

  • 0 in reply to dabuan
    Guru 20755 points

    Hi Drew,

    Yes, I'm using GPIO8_11 to supply power to the PHY, but it is not EVM board , but a custom board. 

    I do not have a block diagram at hand right now, I will give more information when I have it, but Is there any problem in using this GPIO in a custom board ?

    Best Regards,

    Ran

  • 0 in reply to ranchu
    TI__Genius 14545 points

    Ran,

        GPIO's cannot be used to source current to the Power Pins of PHYs. GPIO's have limited current sourcing/sinking abilities and were not designed to power other devices devices. Please reconnect the PHY power pin to a supply on your board.