• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 98 subscribers
  • Views 2320 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Configure CPU Frequency of the AM335x

Wajdi
Intellectual 1375 points
Other Parts Discussed in Thread: SYSBIOS, AM3359

Hi,

I am trying to implement some Benchmarks for my customer Schneider Industry in germany. I am using for this the IDK (AM3359). My Code is based on sysbios and the intialization is done using the gel files of am335x_sysbios_ind_sdk_1.0.0.3. My customer needs the Benchmarks for different CPU-Clock frequencies, since they are planning to use a device with 275MHz.

First issue i had is that the OPP50 of the Gel File deosn't work. Second even if i change the function ARM_OPP100_Config( MPU_PLL_Config( CLKIN, 23, 550 to 275, 1), I get the same benchmark results in term of CPU cycles.(This is can not be correct because i have a lot of memorz access and this will results in a higher cycles counts for a higher CPU frequency)

 

So my question is: Is there any possiblity to change the CPU Frequency to 275MHz and to check wether it is changed or not. Is there any Gel File with an operating OPP50 initialization?

 

regards,

Wajdi

  • 0
    Guru 10085 points


    Hi, Wajdi.
    I also need to know how to change the CPU Frequency to 275MHz.
    Did you find out the solution?

    Regards,
    Kanae

  • 0 in reply to Kanae
    TI__Intellectual 1375 points

    Hi Kanae,

    yes you can change the CPU Frequency using the GEl file: you can simply change the ferequency to 275 in the following file ARM_OPP100_Config( MPU_PLL_Config( CLKIN, 23, 550 to 275, 1),

    the second possibility is to use the functions in the Starterware(Change or reuse the boatloader functions): in File bl_am335x in C:\ti\AM335X_StarterWare_02_00_00_05\bootloader\src. you can find the functions MPUPLLInit, Corepllinit etc. These function are normally used to set the frequency at boot time. In the file AM335X_15x15.h you can define the OPPs you want to use via macros.

    I hope this helps :)

     

    regards,

    Wajdi

  • 0 in reply to Wajdi
    Guru 10085 points

    Hi Wajdi,
    Thank you for your reply.
    I could check the workig properly.
    So what you meant that OPP50 should be set like this.

    - Operating Performance Points after changing in GEL
    //OPP          VDD             ARM (A8)         DDR2          L3/L4
    //OPP50     0.95V+/-5%   275 MHz          200 MHz      200/100 MHz


    - Operating Performance Points before changing in GEL
    //OPP          VDD             ARM (A8)         DDR2          L3/L4
    //OPP50     0.95V+/-5%   275 MHz          125 MHz      100/50 MHz


    Is my understanding correct?

    Regards,
    Kanae

  • 0 in reply to Kanae
    TI__Intellectual 1375 points

    Kanae,

    you only need to chage the arguments of the function you call for PLL initialization in order to chage the CPU frequency at initialization time.

    In the Gel file you will only find the OPP50, OPP100, OPP120, and Turbo configurations. You can use these functions or write your own to configure the PLL as you want.

    Regards,

    Wajdi

  • 0 in reply to Wajdi
    Guru 10085 points

    Hi Wajdi,
    Thank you for your reply.
    I got it.

    Regards,
    Kanae