DP83826I: Collisions in full-duplex.

Hi Lin,

Thank you for your reply.
I have some questions.

1 : COL Full-Duplex appears to be used in full duplex.
     When would you use this feature in full-duplex?
 

2 : LED2 is flashed when LED2 is set to the collision setting.
     What does this mean?

BR.
Kengo.

Hi Kengo,

May I ask why did you need collision setting in full duplex?

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Regards,

Hillman Lin

Hi Lin,

I am doing this as an experiment.
Could you answer my question as it can be set up in full duplex?

BR.
Kengo.

Hi Kengo,

We will discuss with the team and provide you a response later this week.

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Regards,

Hillman Lin

Hi Lin,

How about it?
I'll wait for your reply.

BR,
Kengo.

Hi Kengo,

Sorry for the late reply I was in the vacation. I am currently still waiting for the answer internally. I will let you know about the reason as soon as possible.

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Sincerely,

Hillman Lin

Hi Kengo,

I double check with the team. Collision function only work with half duplex. We will fix this in the updated datasheet.

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Sincerely,

Hillman Lin

Hi Lin,

Thank you for your double check.
I understood about collision.

However, LED2 is flashed when LED2 is set to the collision setting.
Do you have any ideas why it flashed?

BR,
Kengo.

Hi Lin,

Thank you for your reply.

I have some questions about LED2.
1 : You said always flash. 
     However, my customer's checks show that it is not always flashing.
     Please let me know under what conditions it flashes, the cycle, etc.

2 : If led2 is set to the collision setting, are there any other operational problems besides the flashing?

Sincerely.
Kengo.

Hi Kengo,

LED2 flush when there is an TX_RX event.

We don't recommend setting LED2 to collision mode. Are you able to change LED2 functionality to other mode through register 0x0305?

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Thank you,

Hillman Lin

Hi Lin,

>LED2 flush when there is an TX_RX event.
 Could you tell me more detail about an TX_RX event?

>We don't recommend setting LED2 to collision mode. 
 Now it is difficult to change the setting.
 There is no mention in the datasheet that it is not recommended.
 Customers are concerned about what kind of problems they might experience.

BR,
Kengo,

Hi Kengo,

Could you read register 0x0305 to see what is the functionality LED2 is current acting?

Could you also read the register 0x467 and see what is the initial strapping on your board?

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Regards,

Hillman Lin

Hi Lin,

I'll check with my customer.
0x0305 ; 08h
 0x467 ; check

And, could you tell me additional questions?

I choose Auto-negotiation.
How can I configure the settings to check for collisions when half-duplex communication is used?

Can I check the datasheet for collisions for half-duplex communication?

BR.
Kengo.

Hi Kengo,

• TX_RX activity will make LED blink is when there are activity on the MDI lines.
• you can configure it in half duplex by setting register 0x0004 bit 6 and bit 8 to 0 and program a soft reset and/or unplug and re-plug the cable.

May I ask are you facing any functionality issue other than LED2 status?

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Regards,

Hillman Lin

Hi Lin,

Thank you for your support.

>May I ask are you facing any functionality issue other than LED2 status?
 -> No, we do not have some issue.
      Just flash LED2 status.

My customer are set to 100Base-T full duplex with the auto-negotiation feature.
However, they would like to check the occurrence of collision with LEDs when the half-duplex setting is used.
What is the recommended LED2 setting?

And, you said
"Collision function only work with half duplex. We will fix this in the updated datasheet." before on this E2E.

Am I correct in assuming that this means to remove the item of collision in full duplex?
In half-duplex, we can see the collision in LED2, right?

BR,
Kengo.

Hi Kengo,

• We recommend using LED2 functionality instead of COL functionality
• Yes, you are correct. in half-duplex, you can see the collision in LED2

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Regards,

Hillman Lin

Hi Lin,

Thank you for your reply.

In the case of auto-negotiation, when should I set the collision setting for LED2?
This is because full duplex and half duplex require a different setting for LED2.

BR.
Kengo.

Hi Kengo,

If your system is running in full duplex. We would recommend configure LED2 into LED configuraiton.

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Regards,

Hillman Lin

Hi Lin,

When either running half-duplex or full-duplex, could you give me detailed register settings on LED2 when and how to set them up?
I'm confusing LED2 in full duplex and half duplex.

BR.
Kengo.

Hi Kengo,

COL is only used for when customer is running half duplex, so LED2 pin is recommended to configure in COL status if customer concern about collision in half duplex

When customer is running full duplex condition, there will be no collision occur in full duplex. LED2 normally recommended to configure in general LED status.

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Regards,

Hillman lin

Hi Lin,

Should I change the LED2 setting after the half-duplex communication setting has been determined?

BR.
Kengo.