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The error occur when we boot c6678 through SPI

YUCHAO WANG
Expert 1265 points

Hi TI engineer:

         We have successfully boot c6678 through SPI(from nor flash),but some errors happen sometimes(about 1 time in 5 attempt).Errors are described following:

         1.SPICLK is 6.3MHz after power on(when OK,it's 20MHz).And it take much longer time than usual to finish the boot.When boot is completed,6678 begins to run and configure the PLL,we will find the PLLSTAT keep in GO operation, and PLLRST in PLLCTL reg keeps in asserted.It never happen during the JTAG debug.

          2.SPICLK stay in 500KHz in quite a short time after power on,then disappear soon.And none of the core is booted.

         We have checked the signal carefully and find nothing wrong.So we ask for some help.Could anyone give us some advice on how these errors happen?Thank you very much.

  • 0
    TI__Mastermind 42545 points

    It sounds like the PLL may not be initialized correctly. The C6678 has a SYSCLKOUT pin which represents the core clock frequency divided by 6. Can you measure the frequency on that pin in both the good case and the failing case?

  • 0 in reply to Bill Taboada
    Expert 1265 points

    Hello Bill:

             we just find some more information ,described as following:

             If we remove the pll_init code in the booted application code,then the whole boot process becomes ok.So it seems like we init PLL too much times.(RBL has initilized PLL once,isn't it?)

             Do you think we initialize the PLL for more than 1 time will make it run incorrectly?

             Regards,

             Yuchao.

             

          

  • 0 in reply to YUCHAO WANG
    TI__Mastermind 42545 points

    Hi Yuchao,

    If you are going to reinitialize the PLL, you need to follow specific steps to ensure that the device operates without problems. These steps are described in the PLL Users Guide. If you are not reinitializing the PLL correctly, the operation of the device can't be guaranteed. 

    Regards, Bill

  • 0 in reply to Bill Taboada
    Expert 1265 points

    Hi Taboada

           Sorry to reply so late.I have checked the data sheet,but I only find the procedure to init PLL from the power-on state,I never find any words about how to "re-init" it.Could you tell me which chart describe it?Or could you tell me the difference between init and re-init?

           Thank you very much.

            Regards,Yuchao