LMK04828: SYSREF CLK out error

JH Shin

Guru 11750 points

Part Number: LMK04828

Hello,

My customer is using the LMK04828 with the following configurations.

slim giro_sub_code.txt

slim giro_sub_code_mac.zip

They confirmed that 75MHz was output with DC selection in SDCLKout13 below. However, when they changed to SR selection, the expected 10MHz output was not obtained.

Please tell us the root cause and solution for the SYSREF output not working properly.

Thank you.

3 months ago

0 Michael Srinivasan 3 months ago

TI__Genius 12490 points

Hi JH,

Have you triggered a SYNC event? The SYSREF outputs will only generate outputs following a SYNC event.

See section 9.3.1 of the datasheet for more information.

Thanks,

Michael

0 JH Shin 3 months ago in reply to Michael Srinivasan

Guru 11750 points

Hi Michael,

Thank you for your reply.

They said that they changed the settings as below based on the information you provided, but the SYSREF output failed.

Please advise on how to resolve SYSREF output error.

Thanks,

0 vicente flores prado 3 months ago in reply to JH Shin

TI__Mastermind 30692 points

Hi JH,
I see you're using a very old software that is now longer supported.
Can you try utilizing the most up to date version of TICSpro? |
First ensure you have the most up to date version and then follow Michael's suggestion of reverting to section 9.3.1 of DS for example on generating SYSREF outputs.

Best regards,

Vicente

0 JH Shin 3 months ago in reply to vicente flores prado

Guru 11750 points

Hello experts,

The customer tried to enable SYSREF output in continuous mode, but failed.

Could you provide an example setup similar to the one below where SYSREF output works properly?

Thanks,

0 Michael Srinivasan 3 months ago in reply to JH Shin

TI__Genius 12490 points

Hi JH,

I would be happy to do - as a matter of fact, I would be able to create your entire configuration and share it with you. Can you please share screenshots of your PLLs (both 1 and 2)? That way, I can ensure that the file will be right for you, and will be able to generate continuous SYSREF signals.

Thanks,

Michael

0 JH Shin 3 months ago in reply to Michael Srinivasan

Guru 11750 points

Hi Michael,

Thank you for your supports.

Here are the captured images.

Regards,

0 Michael Srinivasan 3 months ago in reply to JH Shin

TI__Genius 12490 points

Hi JH,

Attached is the configuration I made. My suggestion would be to trigger a SYNC event (all you need is a rising edge to the SYNC pin), as the SYSREF outputs will not be generated until you do so.

lmk04828_config.tcs

Thanks,

Michael

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LMK04828: SYSREF CLK out error