DP83848M: DP83848M: DUT test mode entering method

Roy Lin1

Part Number: DP83848M

Hi support team,

Our customer has some questions.
Could you provide the 10 / 100 BaseT test mode SOP for DP83848?
It means that the console command to let the PHY send the continuous pattern for 10/100 BaseT, and let scope test the compliance test.

From this tool, they want to force the continuous waveform pattern transmits to scope.

over 4 years ago

0 Justin Lazaruk over 4 years ago

TI__Expert 7040 points

Hello Roy,

I've found some helpful past e2e threads that describe the register configuration needed to perform IEEE compliance testing on the DP83848.

100Base-TX: https://e2e.ti.com/support/interface/f/138/t/491013

10Base-T: https://e2e.ti.com/support/interface/f/138/t/606335

Furthermore, if you need additional information regarding the compliance test-suite and usb2mdio software to access the required registers, the app note below describes how to bring up TI devices for compliance testing.

http://www.ti.com/lit/an/snla239a/snla239a.pdf

Regards,
Justin

0 Roy Lin1 over 4 years ago in reply to Justin Lazaruk

TI__Intellectual 1080 points

Hi Justin,
Thanks for your suggestions.
Did you have the document describe the waveform of TD+/TD- and RD+/RD- during Negotiate?
We want use scope to check why in auto-Negotiate mode the DP83848 cannot fixed at 100MHz.

0 Justin Lazaruk over 4 years ago in reply to Roy Lin1

TI__Expert 7040 points

Hi Roy,

The DP83848 Figure 5-20, Auto-Negotiation Fast Link Pulse (FLP) Timing, shows the expected timing diagram of auto-negotiation pulses. I am unsure what you mean in the question about fixed 100MHz in auto-negotiate mode.

Regards,
Justin

0 Roy Lin1 over 4 years ago in reply to Justin Lazaruk

TI__Intellectual 1080 points

Hi Justin

Our customer connects DP83848 to some Wi-Fi AP or Notebook Lan port, beginning the speed of Lan is 100MHz, but after 3 minutes will decrease to 10MHz. They will record the register of DP83848 at 100MHz mode and 10MHz.
Could you help us to find out the root cause?

Thanks.

0 Justin Lazaruk over 4 years ago in reply to Roy Lin1

TI__Expert 7040 points

Hi Roy,

Is the linked dropped after 3 minutes and re-established at the lower speed? Can you also describe the settings of the PHY, is it enabled for Auto-negotiation? Are there register initializations after power-up?

Regards,
Justin

0 Roy Lin1 over 4 years ago in reply to Justin Lazaruk

TI__Intellectual 1080 points

Because in some link partner ,their device just could run in the 10Mbps communication , so we force the DP83848 to

down speed by programming the flash preventing the delay of long time try up and down.

They that it’s better for them getting back to discuss the issue why in some link partners the DP83848 could not run

in full speed after the auto-negotiation, here they still have some questions

What is the consequence after they forward the register value ?
Why DP83848 pick up the device just can run in 10Mbps ?
What’s the root-cause DP83848 forced to run in 10Mbps ?
Why the LED_0 (link led) is still constantly bright after unplug ?
Could you provide them with the API for easily entering the test mode ?

Thanks

0 Gerome Cacho over 4 years ago in reply to Roy Lin1

TI__Mastermind 39855 points

Hello Roy,

Justin is currently on vacation. We expect to have a response by next week. Thank you for your understanding.

Sincerely,
Gerome

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DP83848M: DP83848M: DUT test mode entering method