AnsweredAssumed Answered

RGMII KSZ9031 TX_CLK not coming

Question asked by Priya Prasad on Apr 24, 2018
Latest reply on Apr 25, 2018 by igorpadykov

Hi there,

 

I have tried to substitute KSZ9021 to KSZ9031 chip in my imx6q based design. As per migration guideline document, we have changed the ISET resistor and our connector is also compatible as per KSZ9031 magnetics requirement (centre tap connected to ground). 

 

As KSZ9021-RN and KSZ9031 are pin to pin compatible, so we have just replaced the former with the later one.

Our test set up is a Linux PC, imx6q based card, both connected to a DHCP switch capable of 100-base T.

 

The observations are

 

1. There is no RGMII_TXC coming from processor to PHY , it is showing simply a high output.

2. Auto negotiation is completed and Link is up.(100-Base T)

3. RGMII_RXC is coming as 25MHZ from PHY, ENET_REF_CLK  is also 25MHZ, coming from PHY

4. We are not able to ping, since DHCP is not completed.

5. Status of PHY registers for KSZ9031

 

ubuntu@nitrogen:~$ sudo mii-tool eth0
eth0: negotiated 1000baseT-FD flow-control, link ok
ubuntu@nitrogen:~$ sudo mii-tool eth0 -v -v
Using SIOCGMIIPHY=0x8947
eth0: negotiated 1000baseT-FD flow-control, link ok
registers for MII PHY 6:
1000 796d 0022 1622 05e1 cde1 000d 2001
4006 0200 7800 0000 0000 4002 03ff 3000
0000 00f4 0000 ff7e 5cfe 0000 0000 0200
0000 0000 0000 052b 0000 0000 0000 034d
product info: vendor 00:08:85, model 34 rev 2
basic mode: autonegotiation enabled
basic status: autonegotiation complete, link ok
capabilities: 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
advertising: 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD fll
link partner: 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD fll

 

 

Any idea what could cause this kind of behavior ?

 

Regards

Priya

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