DP83849i TDR Cable diagnostic

Mario Campeau

Other Parts Discussed in Thread: DP83849I

I have an issue with the Send TDR Pulse bit (bit 11 of TDR_CTL register) that doesn't clear. What are the conditions can provides the capture to be completed?

Here's what I do:

Write 0xC000 in register 16 to enable TDR in 100 Mb

Write 0x01FF in register 17 for start and stop window

Write 0xC900 in register 16 to send TDR pulse at 8 ns width

wait for Send TDR pulse to clear

Read results in registers 18 and 19

Thanks

over 11 years ago

0 Mario Campeau over 11 years ago

Prodigy 185 points

Another point: I only use the DP83849I for TDR. I do not do any other ethernet activity. In this case, is there any setup or initilisation needed?

I can write and read to any registers using MII serial interface.

0 Patrick OFarrell over 11 years ago in reply to Mario Campeau

TI__Mastermind 31600 points

What length and type of cable are you using? Is the cable unterminated on the far end?

Patrick

0 Mario Campeau over 11 years ago in reply to Patrick OFarrell

Prodigy 185 points

Got it figured out. Some registers were not initialized properly (i.e. VAR_CTRL & EDCR). Now it works fine.

Interface

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DP83849i TDR Cable diagnostic