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RTOS/AM4376: Changing MPU frequency

Marcio Borges
Expert 1950 points

Part Number: AM4376
Other Parts Discussed in Thread: AM4372

Tool/software: TI-RTOS


Does TI provides an example on how to change the AM437x MPU frequency?

I want to change the MPU frequency to 800MHz or 1000MHz. It could be in the secondary boot or when the application calls Board_init().

The BIOS.cpuFreq.lo statement on the system configuration file doesn't change any PLL setting.

For the AM437x evem boards, the Board_PLLInit() function in skAM437x.c is empty. It is not empty for other SOCs, like AM571x.

GetInputClockFrequency() function in AM43xx_PLLconfig.gel, sets the MPU frequency to 600MHz, despite that only the AM4372 operates in this frequency (www.ti.com/.../AM4379).

Thanks,
Marcio.

  • 0
    TI__Guru**** 393215 points
    The RTOS team have been notified. They will respond here.
  • 0
    TI__Guru** 116780 points
    Marcio,

    Your observation is correct the Board_PLLinit() function in the Board library is empty for AM437x and AM335x platforms. On these platforms, we expect the GEL file to set the PLL in debug environment and the bootloader to set it up in the production environment.

    You can access the GEL file which runs when you connect to the ARM core in the CCS EMU package located at :
    ccsv7\ccs_base\emulation\boards\evmam437x\gel

    And in the bootloader code, the setting for PLL is at :
    <PDK_INSTALL_PATH>\packages\ti\starterware\bootloader\src\am43xx

    Note that OPP_NOM (600 Mhz ) MPU PLL Lon this device is the default EVM power configuration used with the PMIC. If you need to change the PLL to 800 (OPP_Turbo) and 1GHz (OPP_Nitro) then you need to increase the PMIC voltage setting as described in the data sheet so the SOC can operate at those performance points.

    In software this can be done using PM LLD driver that we provide in the Processor SDK RTOS . PM LLD send s I2C commands to change the PMIC voltage settings. Refer to the pmrtos_measurement application and clock and divider settings is provided in the spreadsheet AM437x_ClockRate_SetConfig_Generator.xlsm at the location :
    <PDK_INSTALL_PATH>\packages\ti\drv\pm\src\pmlib\prcm\V4

    Hope this information helps.

    Regards,
    Rahul
  • 0 in reply to Rahul Prabhu
    Expert 1950 points

    Hi Rahul,

    Thank you for your response. Gave me a good idea where to start.