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DP83822I: RX_ER

Part Number: DP83822I

Hello,

I'd like to know what're the criterion of the RX_ER pin? When RX_ER is asserted high, what're the trigger points? Could you also offer an instant?

Very thanks.

Regards

Brian W

  • Hi Brian,

    RX_ER will assert high when an error symbol has been detected within a received packet. Basically, if there are any errors in a received packet, the pin will assert high.

    Regards,

    Adrian Kam

  • Thanks for reply. Software guys wondering to know the detailed criterions and conditions on how to judge the error symbol! and it should be related to the CRC check, Frame bit error...etc. The reason is that when end-product is doing EMC/Surge/EFT/ESD tests, the system would be error/alarm, and causing motor abnormal spin. So we'd like to know more details about the criterions of this pin function. Very thanks.    

    Regards

    Brian W

  • Hi Brian,

    When RX_ER is asserted high, it indicates there is an error with the received packet, but there is no way to determine the type of error. In order to determine the type of error, you are going to have to read from various registers to see if specific types of errors were detected.

    Regards,

    Adrian Kam

  • We're still wondering to know what's the exact criterion for this pin RX_ER function. This pin should be a necessary pin fort error signals in the EtherCAT application. Software Engineer would like to know the exact error type when received packet find something wrong possibly. How RX_ER is able to indicate the error? It's appreciate if you describe this more details. thanks.   

    Regards

    Brian W

  • Hi Brian,

    The RX_ER pin cannot indicate the type of error. There is no other pin that will indicate the type of error either. To find out the type of error, you will have to read from various registers to see if a specific type of error is detected.

    Regards,

    Adrian Kam

  • Hi Adrian,

    Thanks. The correct question is how to judge the packet error on the received packet? Are errors caused by the high latency, jitter increases, or higher loss rates? What exact factors are monitored by DP83822 PHY to indicate RX_ER pin High? Customer would like to know the details. Could you help on this! Very thanks.

    Regards

    Brian W

  • Hi Brian,

    In your example, high latency, jitter increases, and/or higher loss rates, can cause errors to the receiving packet, which will cause RX_ER to be high. However, the PHY cannot indicate which of the three caused the error. The DP83822 does not monitor any specific factors. As long as there is an error in the packet, which can be caused by a multitude of factors, the RX_ER will assert high.

    Regards,

    Adrian Kam 

  • To add to the previous reply, in order to figure out the exact cause of the error, you will have to use an oscilloscope and look at the signals directly.

  • Thanks. Customer would like to know further info. about criterions in the PHY.

    For example: How to judge if below has error or out of specifications?        

     

    high latency:

    jitter increases:

    higher loss rates:

     

    Regards

    Brian W

  • Hi Brian,

    The PHY cannot monitor/judge if the specifications you listed is out of specification. In order to determine if they are out of specification, that has to be done through user observation or a second peripheral device that focuses on monitoring those specifications.

    Regards,

    Adrian Kam

  • Here are following questions about RX_ER details.

     

    1. Does RX_ER only occur when abnormal data cannot be converted correctly when detecting 5B to 4B in the Link state?

     

    2. When the above behavior occurs (RX_ERR), how can the signal be synchronized back, or will another auto-negotiation process be required?

     

    Customer software guys still like to figure out in detail about RX_ER pin. Please describe more detail as much as possible. thanks.  

     

    Regards

    Brian W

     

     

     

  • Hi Brian,

    1. Yes, that is correct. However, only one RX_ER assertion will not drop the link. It usually takes multiple RX_ER assertions to drop link. If fast link drop is not enabled, it will take some time until link is dropped.
    2. That depends on the cause of the error. For example, if the problem is EM issues, once the EM issues go away, then resetting will help. However, if the problem is a wrong clock, then resetting will not do anything.

    Regards,

    Adrian Kam