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LMK03318: LMK03318 does not ouput clock after register setting

JH Shin
Guru 11270 points
Part Number: LMK03318


Hello,

My customer encounts an issue that the LMK03318 does not output the clock signals even though the registers are set normally after power on.

  - On-chip EEPROM is not used and the registers are set with I2C after power on.

  - The symptome occurs about 1 to 4 times in 60 power-on resets.

  - the register setting values are attached.as a file.

   - When this issue occurs, reset to RESETN_SW(R12) would output the clock normally.

1. Please let us know what caused this issue and how to fix it.

2. Can the software reset after setting the registers cause problems with the device normal operation?

0121.LMK03318_Register.xlsx

Thanks in advance.

Best Regards,

JH

  • 0
    TI__Genius 11900 points

    Hello JH,

    A software reset is actually encouraged to ensure all the internal state machines start from a good point.

    Thanks,

    Vibhu

  • 0 in reply to Vibhu Vanjari
    Guru 11270 points

    Hi Vibhu,

    Thank you for your reply.

    Could you please advise what caused  the issue ?

    When there was no clock output, LOL and LOS status were normal. Are there any alarms to detect that there is no clock output?

    Thank you.

    Regards,

    JH

  • 0 in reply to JH Shin
    TI__Genius 11900 points

    Hello JH,

    It could be something to do with the internal state machine. The device might have been stuck in an unknown state after the PLL settings were changed.

    Every time the PLL settings are changed it is recommended to do a soft reset.

    When you say LOL and LOS were normal, do you mean the device indicated lock?

    Thanks,

    Vibhu

  • 0 in reply to Vibhu Vanjari
    Guru 11270 points

    Hello Vibhu,

    Yes, There were no alarms in register R13.

    Best Regards,

    JH

  • 0 in reply to JH Shin
    TI__Genius 11900 points

    Hello JH,

    These are not sticky bits, these bits indicate the current status of the register. It may be beneficial to use one of the STATUS pins to indicate LOL for debug purposes, that way you can see the LED turn on or off.

    Thanks,

    Vibhu

  • 0 in reply to Vibhu Vanjari
    Guru 11270 points

    Hello Vibhu,

    Please explain in more detail.

    What does it mean that LOL and LOS of R13 indicate the current status of the register? Doesn't it indicate PLL status at the moment of reading?

    What STATUS pin setting should be selected for the LED turn on or off ? Does it keep updating the current PLL's lock status? or does it remain changed once?

    Thanks a lot.

    JH

  • 0 in reply to JH Shin
    TI__Genius 11900 points

    Hello JH,

    Yes, the LOL and LOS in R13 indicate the current status, status at the moment of reading.

    INT_FLAG register R16 can be used to see if the device ever flags LOS or LOL. INT_FLAG register is used along with INT_FLAG_POL (R15), INTCTL (R17) and INT_MASK (R14). Please read the descriptions of these in the register maps if they are of interest.

    For example, if the device loses lock and regains lock, R13 will indicate lock, while R16 will indicate the device has lost lock in the past until cleared.

    The STATUS pins are similar to  the INT_LIVE registers, however, if you are looking at the LMK03318EVM board you will be able to see the LEDs turn on/off.

    R27 and R28 can be configured to indicate different signals on STATUS0 and STATUS1 pins.

    Thanks,

    Vibhu

  • 0 in reply to Vibhu Vanjari
    Guru 11270 points

    Hello Vibhu,

    As you said, if R13 shows the lock staus of the PLL in real time, I can't detect that there is no clock output even if I use the STATUS pin.

    How to monitor only the output of the LMK03318?

    Thank you.

    JH

  • 0 in reply to JH Shin
    TI__Genius 11900 points

    Hello JH,

    I am not sure if I understand your question correctly.

    JH Shin said:

    How to monitor only the output of the LMK03318?

    You can monitor the STATUS0 or STATUS1 pins on a scope and trigger on changing an edge or you can look at the LEDs. Additionally you can use the interrupt registers.

    Thanks,

    Vibhu