W5300 vs W5300 connection link problem

i have 2 modules with W5300 chip in one rack, so they have equal power, reset timings and behavior.
Each W5300 chip is used in MACRAW mode.

I noticed no Link signal when they are directly connected after power on or system reset . This is a very often situation.
When connecting to switch or notebook Link is alway ok. Connecting them after other devices disconnection is also always ok.

I could solve this problem partly by applying a delay about 30 - 50 msec before hardware reset of w5300 chip on one of modules.

Each module must be equal with the same software.

How can i solve this problem?

Thank you!


I tested about your issue but all link has no problem.

Plz, attach your schematic in this post.

schematic in attachment.
There are Bourns TBU protectors in tx, rx cirquits between RG connector and transformer (~10 Ohm resistance).
I tested with removed protectors. No changes in behavior.

More W5300 schematic part in attachment.

I have made a few more researches.

After power on and reset when cable is unplugged on oscilloscope i can see autonegotiation Fast link pulses sequence 2 ms length with period of 16 ms. On tx and on rx pin (because of auto MDI/MDIX i think).

After this i connect second W5300 module with straight ethernet cable and after power on take an oscilloscope.
And now i can see second Fast link pulses sequence from the second W5300 module. Two sequences are synchronously
but shifted for ~1 msec so one sequense is partly covered by the other. And this shift is drifting until sequenses are not covered any more. This takes about 50 - 53 seconds. After this appears link signal.

What can you say about this problem?

The circuit is no big issues. Have you ever Power-on-Reset did apply?
If you do not correctly Reset, the link may fail to occur. Reset secure a lot of time.
And if the link is successful late, Ethernet PHY fixed setting and testing.
Another way, the Ethernet line protection circuitry is removed and tested.