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TMS320F280041C: Reg:clock frequency decreasing after power OFF and ON the controller.

Part Number: TMS320F280041C


I am using TMS320F280041C controller.

In this controller I have loaded code with clock configuration by using the single ended external oscillator. while running code in controller without power-off i have seen the xclkout through the pin it is working fine. After power OFF and ON again i am checking the xclkout on the pin it is getting very less frequency.

I have configured the Syspll clock for 100mhz with external oscillator(single ended).

Can i found any solution for this problem.

with regards,

Nithin kumar

  • Hi Nithin,

    Is your clock configuration coded loaded in Flash, and does it also include enabling SYSCLK to XCLKOUT?

    When you say power-on and power-off are you power cycling your board?

    Can you also dump the CLK_CFG_REGS, when the frequency is low?

    When you power-on again, are you connected to CCS?

    Please share more details on how you power cycled the device and also how are you executing your code.

    Best Regards,


  • Hi Nirav,

    I am confirming my code loaded in the flash or not by toggling the GPIO it is happening fine because of decreasing clock frequency it is occurring more delay in toggling.

    while checking we observed that default it is taking internal oscillator clk freq as system clock after power OFF and ON.

    After loading the code i am removing the power supply and again i am giving the power supply for checking the application then we observed current drop and XCLKOUT frequency is decreased.

    Can you also dump the CLK_CFG_REGS, when the frequency is low? (I didn't understand this question what is mean by this).

    NO iam not connecting the CCS again after power off and ON.

    with regards,


  • Hi Nithin,

    When you loaded the code, and were connected to the CCS, did you check GPIO toggling, and was it happening at SYSCLK frequency i.e. 100Mhz rate?

    Also, when you power back ON is your code executing from Flash correctly? Meaning are you sure it is locking the PLL and configuring SYSCLK to PLL Clock? By default SYSCLK=INTOSC, so if you want to use PLLCLK you need to configure PLL and use it as as system clock by PLLCLKEN=1 in your code.

    Best Regards,