DP83822IF: RX Error count(Receive Error Count Register (RECR))

Hirotaka Matsumoto

Part Number: DP83822IF

Hi all

Would you mind if we ask DP83822?

<Question1>
When RD+ and RD are inserted invalid data, will RX Error count( Receive Error Count Register (RECR)) increase?
Or, does RX Error Count mean that there is error between PHY and CPU(MAC I/F)?

<Question2>
In relation to <Question1>, depending on an incorrect action of TXD0, does Link loss occur?
About Link loss detection, isn't TXD0 relation to Link loss?

Kind regards,

Hirotaka Matsumoto

over 7 years ago

0 Rob Rodrigues over 7 years ago

TI__Mastermind 19780 points

Hi Hirotaka-san,

<Question 1>
RX_ER occurs when the DP83822 receives an invalid symbol on the line from the connected PHY across RJ45. RX_ER does not mean communication between DP83822 and MAC had an error. This is most usually caused by high jitter on one of the PHYs in the link. It could be the transmitting PHY and it could be the receiving PHY.

<Question 2>
TX_D0 is a data bit. If there is an error on TX_D0, DP83822 will not indicate a problem, but will transmit the incorrect bit as commanded by the MAC. The PHY is not intended to provide data integrity. The MAC and higher layers are used for that function.

The PHY can be blamed for data corruption only IF the MAC transmits the proper data to the PHY, and the receiving PHY across the RJ45 indicates a RX_ER or the receiving MAC has a problem with data. Then you must start to debug which PHY is causing problems.

Best Regards,

0 Hirotaka Matsumoto over 7 years ago in reply to Rob Rodrigues

Guru 27585 points

Rob san

Thank you so much for your coopreation always!

We have some additional questions as follows;

<Question1>
There is the description as follows on the datasheet P43,
"RX Error Count - when a predefined number of 32 RX_ERs occur in a 10μs window, the link will be dropped."
Do these RX_ERs mean "Table 35. 0x0015 Receive Error Count Register (RECR)"?
When Receive Error Count Register is 0x14, Link down occurs.
When bit 01000 = RX Errors of address 0x000F：Fast Link Down Status Register (FLDS) is high, it seems that Link down occurs.

<Question2>
And then, just in case, could you let us know how much Rbias voltage normal value?
1.0V～1.2V??

We appreciate your help always.

Kind regards,

Hirotaka Matsumoto

0 Hirotaka Matsumoto over 7 years ago in reply to Hirotaka Matsumoto

Guru 27585 points

Rob san

We are sorry to rush you, could you give us the reply about <Question2>?

Kind regards,

Hirotaka Matsumoto

0 Ross Pimentel over 7 years ago in reply to Hirotaka Matsumoto

TI__Mastermind 23675 points

Hi Matsumoto-san,

RX_ER counter is in register 0x15h. This is the register that is referred to in the FLD section.

RBIAS should be in the range of 1.0V - 1.3V.
However, the key is to have RBIAS resistor as 4.87kohm.

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DP83822IF: RX Error count(Receive Error Count Register (RECR))