DP83848Q-Q1: How to disable the CLK_Out

Johannes Konert

Part Number: DP83848Q-Q1

Hi Team

for EMC tests our Customer wants to disable the CLK_OUT of the DP83848Q-Q1 as descirbed in the Elect. Characterisation Table

Pleas provide a detailed describtion how to do this!

Kind Regards

Johannes

13 days ago

0 Gerome Cacho 13 days ago

TI__Mastermind 44955 points

Johannes,

Please refer to this FAQ for disabling CLKOUT.

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1452956/faq-dp83848q-q1-how-to-disable-25mhz-clkout-output?tisearch=e2e-sitesearch&keymatch=DP83848#

Sincerely,
Gerome

0 Johannes Konert 12 days ago in reply to Gerome Cacho

TI__Prodigy 60 points

Hi Gerome,

thanks for the LINK, but within the FAQ it says "If the CLKOUT output is not used on DP83848, it may be disabled using the below register writes.

0x13[0] = 1
0x15[14] = 1

Please confirm that writing to those registers does turn off the CLK_OUT, because our customer tested it already without any success!

Kind Regards

Johannes

0 Gerome Cacho 12 days ago in reply to Johannes Konert

TI__Mastermind 44955 points

Hi Johannes,

I believe these are the proper settings to disable CLKOUT, and this has been verified by other customers. If your customer is failing to accomplish CLKOUT disable, we might need to take a deeper look into the SMI.

Can you please confirm they have good SMI functionality by requesting a readback of Reg 0x2 and 0x3? These are read-only registers which have specific value.

Afterwards, can they alter Reg 0x0 by disabling auto-negotiation and then read that value back to confirm write and read-back capabilities?

Sincerely,

Gerome

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DP83848Q-Q1: How to disable the CLK_Out