DP83TC814S-Q1: Serial Management Timing Issue

Jingkun Wang

Intellectual 295 points

Part Number: DP83TC814S-Q1

Tool/software:

Hello TI Team,

Below is DP83TC814S-Q1's SMI Timing SPEC:

Below is MAC's SMI Timing SPEC:

When MAC reads, from the PHY MDIO output timing can't match MAC requirement.

PHY MDIO changes the data after the MDC rising.

MAC requires the MDIO change data after the MDC falling.

Now, its hold time is too short and setup time is long.

Can PHY change the output timing?

Best Regards!

over 1 year ago

0 Melissa Chang over 1 year ago

TI__Genius 14006 points

Hi Jingkun,

The data should be sampled after MDC rising. This is defined by the IEEE802.3 Standard, in the section '22.3.4 MDIO timing relationship to MDC'. Unfortunately, I don't believe we can change this on the PHY side.

What is the part number of the MCU? Have you been able to confirm with MCU vendor that they cannot sample on the rising edge? It is a bit odd if they are not following the spec.

Best regards,

Melissa