DP83TC812R-Q1: DP83TC812R-Q1

sanjone tu

Tool/software:

question:The reading of PHY id is 0xFFFFFFFF, and the values of VDD are ok. May I ask what other hardware circuits may cause that the phy id cannot be read ? Or other reasons？

The hardware schematic diagram is as follows：

over 1 year ago

0 David Creger over 1 year ago

TI__Mastermind 27952 points

Hi Sanjone,

There are a number of reasons why MDC/MDIO access may be failing. We have available DP83TC812 troubleshooting guide, please see section 4 and perform the recommended checks. Let me know which checks you are able to successfully complete.

Thanks,

David

0 sanjone tu over 1 year ago in reply to David Creger

Prodigy 20 points

HI David:

The test results are as follows:

VDDMAC=2.5V ,

VDDA=3.3v.

VSLEEP=2.5v,(this is not in conformity with requirements)

RESET_N and INH all high;

CLKOUT no signal;

0 David Creger over 1 year ago in reply to sanjone tu

TI__Mastermind 27952 points

Hi Sanjone,

You are correct, VSLEEP requirement is not met. This pin should be supplied with 3.3V always on supply. Additionally the WAKE pin should be connected to 3.3V. I also see that 1.0V is supplied to pins 9 and 21 which should not be the case. It looks like this design was copied over from a different PHY design. Please have a look at the DP83TC812 Schematic Checklist.

Thanks,

David

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DP83TC812R-Q1: DP83TC812R-Q1