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AM3351: Best way to increase CPU clock frequency

Randhir Kalsi
Expert 4545 points
Part Number: AM3351

Hello team,

Hope you are well.

A customer is using AM3351BZCE60 part and have noticed that the ROM code sets up the PLL for 300Mhz operation.

How can the customer increase the CPU clock frequency as the spec suggests that this device could go up to 600Mhz.

  • 0
    TI__Guru** 116170 points

    Randhir,

    Can you please specify which boot mode is the device booting in and what is the input clock used to the SOC. also how is the customer measuring the PLL is at 300 Mhz. 

    Is the device configured to OPP120 to  operate at 600Mhz? Also specify if the customer is using RTOS or Linux software so that we can provide guidance accordingly.

    The device clocks are usually setup using PLLCTL registers. Has the customer looked at these registers. If possible please provide the CLKIN and PLL register dumps.

    Regards,
    Rahul

  • 0 in reply to Rahul Prabhu
    Prodigy 190 points

    Hi Rahul,

    Thanks for the reply. I'm not sure what you mean by boot mode, could you clarify?

    Input clock is from a 24Mhz source.
    Speed is 'measured' by checking BogoMIPS, as cpufreq is not present on the system (more on that in the thread linked below)
    Using Linux, the 03.00.00.04 SDK.
    The device should be at OPP100, but if you have a suggestion on where to check that I'd be happy to confirm.
    Could you let me know what address you'd like dumps of?

    EDIT: We are using the AM3351BZCE60, which should be capable of 600Mhz? 

    I'd previously started a thread here:

    e2e.ti.com/.../2091826

    It might be best to consolidate discussion to one thread.

  • 0 in reply to Tim Elmore
    Prodigy 190 points
    So I pulled the CM_CLKSEL_DPLL_MPU register (0x44E0042c)

    and it yielded:

    0x00012C17

    Which is a multiplier of 300 and a divisor of 24, and the input clock is 24, so that’s a clock speed of 300Mhz.