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How to increase clock speed?

Rohini Srinivas
Intellectual 385 points

Hi,

I am using DM814x evaluation board. The current speed is about 600+MHz. But the processor support given in docs is 1GHz..

Please could I know how we could increase the speed of the processor?

Regards,
Rohini

  • 0
    TI__Guru**** 393215 points
    Hi Rohini,
     
    First of all you must make sure that your EVM processor supports 1GHz. The processor should be marked with CYE1 or CYE2. CYE and CYE0 do not support 1GHz. Then you have to modify both frequency (1.) and core voltage (2.) to achieve 1GHz speed:
     
    1. MODENA_M parameter is located in ti-ezsdk_dm814x-evm_5_xx_xx_xx/board-support/u-boot-2010.06-pspxx.xx.xx/arch/arm/include/asm/arch-ti81xx/clocks_ti814x.h file:

    #define MODENA_M   0x64 //0x3C
     
    After you made this modification, you need to rebuild the u-boot (1st stage and 2nd stage) and boot the device with this new u-boot.
     
    2. When booting with the new u-boot, you need to interrupt the countdown to enter in the 2nd stage u-boot command line, where you switch to the higher voltage:
     
    TI8148_EVM#i2c mw 0x2D 0x22 0x3C
     
    After that you just need to boot the Linux kernel with the boot command:
     
    TI8148_EVM#boot
     
    And this is all.
     
    Best Regards
    Biser
  • 0 in reply to Biser Gatchev-XID
    Intellectual 385 points

    Hi Biser,

    Thanks for your quick reply. I have checked the processor on our board here. I saw CYE in two places.Not sure which I should consider.

    I have attached a snap shot of the processor. Please could you confirm if it supports 1GHz.

    Regards,

    Rohini

  • 0 in reply to Rohini Srinivas
    TI__Guru**** 393215 points
    Hi Rohini,
     
    If this is on your EVM, it could very well be a pre-production part, so no telling really. We had the same issue with another client recently, and their EVM (very similar marking) worked at 1GHz. I've attached a picture of that for you to compare. Perhaps you could try and see what happens. Just keep checking the processor temperature, to make sure it doesn't overheat.
     
    BR
    Biser
     
  • 0 in reply to Biser Gatchev-XID
    Prodigy 200 points

    Hi,

    I am trying to use a CYE2 DM8148 too, and found your answer useful. However, reading the DM8148 data-sheet page 186, I find many frequencies can be increased. Most of them may be found in clock.h, except for the "media controller" frequency. I assume it is the PLL clocking the cortex M3 co-processors. Could you tell us which file to modify in order to increase this PLL frequency?

    Regards.

  • 0 in reply to Gilles Chanteperdrix
    TI__Guru**** 170625 points

    Hi Gilles,

    According to the DM814X TRM, the Media Controller frequency is controlled from the DPLL_ISS. You need to modify DPLL_ISS parameters (which are in the clocks_ti814x.h file).

    Best Regards,

    Pavel

  • 0 in reply to Pavel Botev
    Prodigy 200 points

    Ah, thanks, there is a fixed "divide-by-2" and the same PLL is used for the two table columns ISS and Media ctrl. then?

  • 0 in reply to Gilles Chanteperdrix
    TI__Guru**** 170625 points

    Yes, this is correct.

    Best Regards,

    Pavel

  • 0 in reply to Pavel Botev
    Intellectual 510 points

    Hi Pavel/Biser

    Currently, our custom board uses CYE0 devices. We are exploring the option of using OPP166 for our next proto version since the processing speed of the CYE0 device(ARM:720 Mhz & DSP:600MHz) seems to insufficient for our application.

    Hence, we would like to BGA rework one of our existing proto board and replace the CYE0 device with CYE1/CYE2 device before doing our next PCB spin. Biser's earlier post (#2) in this thread gives details on changes the uboot to achieve higher operating speed by configuring both frequency of DM8148 and PMIC Output Voltage settings. Is it sufficient or do we need to make any other hardware changes to our existing board apart from the BGA rework?

    Thanks as always!

    Regards,

    Padmanabhan

  • 0 in reply to Padmanabhan KS
    Intellectual 510 points

    Another question is if we use the currently CYE0 chip and make the changes in uboot as mentioned by Biser, would the chip be still functional? I understand that CYE1/CYE2 devices need to be used for OPP166 but just for sake of understanding, is overclocking allowed?

    Regards,

    Padmanabhan

  • 0 in reply to Padmanabhan KS
    TI__Guru**** 170625 points

    Padmanabhan,

    Padmanabhan KS said:
    Is it sufficient or do we need to make any other hardware changes to our existing board apart from the BGA rework?

    From the HW side, I think no other HW changes are needed, as these devices are compatible.

    From SW side, you should consider the silicon revision of the device (1.x, 2.x, 3.x).

    Best regards,
    Pavel

  • 0 in reply to Padmanabhan KS
    TI__Guru**** 170625 points

    Padmanabhan,

    Padmanabhan KS said:
    Another question is if we use the currently CYE0 chip and make the changes in uboot as mentioned by Biser, would the chip be still functional?

    No, the changes are for ARM A8 at 1GHz, while CYE0 ARM A8 supports max 720MHz.

    Padmanabhan KS said:
    I understand that CYE1/CYE2 devices need to be used for OPP166 but just for sake of understanding, is overclocking allowed?

    CYE0 Cortex-A8 ARM can be overclocked from 600MHz to 720MHz.

    Regards,
    Pavel

  • 0 in reply to Pavel Botev
    Intellectual 510 points

    Thanks, Pavel.

    Apart from the above mentioned steps for ARM speedup, please confirm if the below is the only thing which is needed for speeding up the DSP as mentioned in another thread:

    To increase the DSP frequency from 500MHz (OPP100/1.2V) to 750MHz (OPP166/1.35V), you need to perform two steps:

    1. Modify the DSP PLL parameters (DSPPLL registers)

    2. Change the core voltage from 1.2V to 1.35V

    Regards,

    Padmanabhan

  • 0 in reply to Padmanabhan KS
    TI__Guru**** 170625 points

    Padmanabhan,

    Padmanabhan KS said:

    please confirm if the below is the only thing which is needed for speeding up the DSP as mentioned in another thread:

    To increase the DSP frequency from 500MHz (OPP100/1.2V) to 750MHz (OPP166/1.35V), you need to perform two steps:

    1. Modify the DSP PLL parameters (DSPPLL registers)

    2. Change the core voltage from 1.2V to 1.35V

    I confirm.

    See also the below e2e thread:

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/327038.aspx

    Regards,
    Pavel