RGMII interface - Rx - Ok, Tx - ?

Hi, I am using a board with RGMII interface and facing some problems w.r.t reception(Rx) and transmission(Tx) of packets. I am trying to diagnose the problem.

Is it possible that a port of a RGMII interface can work properly only for Rx(Receiving data) and not for Tx(Transmitting data).

That is, whenever there is a problem/damage in a RGMII interface, will it stop doing both reception and transmission ? Any ideas ?

Thx in advans, Karthik Balaguru

Reply to
karthikbalaguru
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Yes. Especially if TxC is bad.

Damage? Odd choice of words. But anything is possible; you need to understand the software too.

Get the data sheet, a logic analyzer, a good software debugger and a packet sniffer.

Reply to
LittleAlex

The same software is working fine in another board with RGMII interface. The problematic board is able to receivethe packets but it is not transmitting any packets. Initially suspected some setup configurations and software, but it does not look like it. ARP entries, the MAC addresses and IP addresses etc look fine.

Using Wireshark(Ethereal) analyzer to log the packets & to track the request-response flows. Need to check if there is any specific register available with RGMII interface that would convey if it is really sending (transmitting) the packets out before deciding on this.

Lemme know if you have any tricks/ideas.

Thx in advans, Karthik Balaguru

Reply to
karthikbalaguru

Be sure that you are transmitting a good (valid) packet. I was using Wireshark for a very similar test and if the packet is not value, the interface receiving it will throw it away without passing it up to Wireshark.

I also had problems with a network switch not delivering the data to the connection that the Wireshark machine was on, so the data was going onto the network, but Wireshark didn't get it.

Also check the the tx_en and tx_er signals are good. The MAC might be transmitting without the PHY sending on the data.

Scott

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Reply to
Not Really Me

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I did not find tx_en and tx_er. Can you pls confirm the specification that you are referring to. I got

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As per the above specification, I think, i need to check the TXC, TXD and TX_CTL . Are you referring to GMII_TX_ER and GMII_TX_EN ?

Thx in advans, Kartik Balaguru

Reply to
karthikbalaguru

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