LMK05318B: DPLL is taking SECREF as active instead of going to Holdover mode

MURALI PT

Part Number: LMK05318B

Hi,

I am using LMK device, I am feeding only PRIREF to this device. SECREF input is unconnected.

If I disable PRIREF input then I expect the device to go to hold-over mode, But instead I see it is switching to SECREF. How I can resolve this problem?

over 2 years ago

0 MURALI PT over 2 years ago

Prodigy 70 points

Attached Image showing, DPLL is locked to SECREF instead of Hold-over

0 vicente flores prado over 2 years ago in reply to MURALI PT

TI__Mastermind 29132 points

Hi Murali,
To better assist you can you share your .tcs configuration with us?

Regards,

Vicente

0 MURALI PT over 2 years ago in reply to vicente flores prado

Prodigy 70 points

Hi, I have attached the tcs file.

Gamora_PFE_LMK05318B_GEN2_PTP_rev3.tcs

0 Jennifer Bernal over 2 years ago

TI__Genius 16545 points

Hi Murali,

Are you using the LMK05318BEVM? If not, please send your schematics.

Regards,

Jennifer

+1 Jennifer Bernal over 2 years ago in reply to Jennifer Bernal

TI__Genius 16545 points

Since you are using PRIREF only, please try with the following settings instead:

DPLL_REF_MAN_SEL, R251[5] = 0x00, manually select DPLL reference by register
DPLL_REF_MAN_REG_SEL, R251[4] = 0x00, manually select PRIREF
DPLL_SWITCH_MODE, R251[1:0] = 0x03, set to manual holdover

DPLL switching mode descriptions:

0 Jennifer Bernal over 2 years ago in reply to Jennifer Bernal

TI__Genius 16545 points

Hi Murali,

Were you able to resolve your issue?

Regards,
Jennifer

0 MURALI PT over 2 years ago in reply to Jennifer Bernal

Prodigy 70 points

Hi Jennifer,

We were able to resolve that issue with that setting. But one changes we have done. We selected DPLL_REF_MAN_SEL = 0x1 Hardware pin REFSEL. REFSEL strapping is pulled-low for PRIREF_SEL. Is this good to go with?

0 Jennifer Bernal over 2 years ago in reply to MURALI PT

TI__Genius 16545 points

Yes, you can also do that method. Instead of using the register setting to select the reference, you can use the hardware pin (REFSEL). If the REFSEL pin is pulled LOW, then PRIREF will always be selected.

Regards,

Jennifer

0 MURALI PT over 2 years ago in reply to Jennifer Bernal

Prodigy 70 points

Thank you.

Clock & timing

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LMK05318B: DPLL is taking SECREF as active instead of going to Holdover mode