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c6657 main PLL Configuration

hi sirs,

I have configured the main PLL at 1000MHz using " evmc6657l.gel " below. but I got 0x02018003 when I check DEVSPEED register(0x026203f8).

C:\ti\mcsdk_2_01_02_06\tools\program_evm\gel

And then I got 0x02018003 whatever I configured the main PLL at.

Could you please let me know why this happen?

Thank you in advance.

bai

  • DEVSPEED is programmed at the factory.  It's not necessarily what you programmed the PLL to.  The BootROM for example will use this along with other latched values that tell it what the input clock speed is inorder to reprogram the PLL to a frequency that is defined by the DEVSPEED.

    In this case DEVSPEED (bits 31:23) is 0x000000100b = 1250MHz.

    If you want to verify the actual frequency you are getting, then you may wish to use an oscilloscope to probe the SYSCLKOUT pin, which operates at 1/6 of the SYSCLK.

    Best Regards,

    Chad