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TMS570LS0714: Probability of erratum SSWF021#45 and workaround's applicability

Part Number: TMS570LS0714
Other Parts Discussed in Thread: TMS570LS1224

Hi BU experts, 

I am asking this question for my customer. It is shown in Errata notes of TMS570LS07xx that there may be PLL fails (SSWF021#45). My customer wants to know the probability of occurrence for this erratum in TMS570LS0714 and TMS570LS1224. 

On the other hand, they want to know if the SW workaround _errata_SSWF021_45_pll1() can detect the failure for PLL2 or not. And if the system only uses PLL1, _errata_SSWF021_45_pll1() is the only workaround should be implemented, right? 

Regards, 

Will 

  • My customer wants to know the probability of occurrence for this erratum in TMS570LS0714 and TMS570LS1224. 

    I don't have this kind of data.

    Hercules MCUs have PLL setup issue on very rare occasons. TI does screen devices before shipping the devices to users. This SW workaround may not be 100% effective, but  can significantly help to reduce the occurrence of failures

    SW workaround _errata_SSWF021_45_pll1()

    _errata_SSWF021_45_pll1() attempts to lock PLL1. This function is to be used on devices that have only one PLL, or in applications that do not use PLL2.

    _errata_SSWF021_45_pll2() is used for PLL2.

    And if the system only uses PLL1, _errata_SSWF021_45_pll1() is the only workaround should be implemented, right? 

    Yes, you are correct.

  • Hi QJ, 

    Please help check with internal team if they have this kind of data or not, thank you. 

    A further question, does PLL2 act as a backup for PLL1? Since customer said in their application PLL2 is not used, but the program/chip is stalling due to PLL2 is in failure (CSVSTAT.CLKSR6V field). So in this situation, workaround for PLL2 should be also implemented? Please help confirm. 

    Best Regards, 

    Will 

  • Please help check with internal team if they have this kind of data or not

    We don't have such data.

    does PLL2 act as a backup for PLL1?

    No, PLL2 is not the backup of PLL1. But you can use use either PLL1 or PLL2 as the clock source for HCLK, VCLK, etc.

    PLL2 is not implemented on TMS570LS0714.

    You can check whether a clock source is valid or not by checking the corresponding bit to be set in the Clock Source Valid Status (CSVSTAT) register. For example, you can check if bit 1 in CSVSTAT is set before using the output of PLL#1 as the source for any clock domain. The bit 6 is used for PLL2.

  • Thank you, QJ.