DP83867CR: “VTM_IDLE_CHECK_CNT_THR” resister

Michiaki Tanii

Expert 4610 points

Part Number: DP83867CR

Hi team,

Could you kindly give us for more detail on “VTM_IDLE_CHECK_CNT_THR” resister.

The background is that our customer has been struggling bad communication.

In the bad communication, customer observe the wrong preamble packet and error signal is asserted at RX_DV/RX_CTRL.

If customer configure the bit to “4” from “5” of default on “VTM_IDLE_CHECK_CNT_THR” resister, the above issues was removed.

To resolve the issue, customer has been considering to configure to the bit “4” but concerned about whether there are any degradation or not.

I would much appreciate if you could provide the detail on “VTM_IDLE_CHECK_CNT_THR” resister.

Thank you and best regards,

Michiaki

over 5 years ago

0 Vikram Sharma over 5 years ago

TI__Genius 16030 points

Hello Michiaki,

Is customer using IPG < 12?

Also I am checking with the design and will get back to you about the functionality of this counter threshold.

Regards,

Vikram

0 Michiaki Tanii over 5 years ago in reply to Vikram Sharma

TI__Expert 4610 points

Hi Vikram,

Customer configure IPG = 12 in the MAC of transmitter but looking at receiver, IPG value is sometimes changed between 8 and 13.

When customer saw the malfunction communication, IPG = 10 or 11 at receiver.

Thank you and best regards,

Michiaki

0 Michiaki Tanii over 5 years ago in reply to Michiaki Tanii

TI__Expert 4610 points

Hi Vikram,

Could you kindly share the latest situation ?

Thank you and best regards,

Michiaki

0 Michiaki Tanii over 5 years ago in reply to Michiaki Tanii

TI__Expert 4610 points

Hi Vikram,

When could we get your feedback ?

We need to explain the reason why we need time to answer the inquiry.

I know you are busy but I would much appreciate if you could understand our situation.

Thank you and best regards,

Michiaki

0 Vikram Sharma over 5 years ago in reply to Michiaki Tanii

TI__Genius 16030 points

Hello Michiaki,

Here is the information :

This determines, how many symbols to look for before declaring it as IDLE.We need to reduce this count to 4 for IPG<12. Also for IPG = 12 we can keep it as 4.

Regards,

Vikram

0 Michiaki Tanii over 5 years ago in reply to Vikram Sharma

TI__Expert 4610 points

Hi Vikram,

Could you advise the reason why the initial value is 5 ?

And are there any concern or degradation by changing to 4 from 5 ?

I would much appreciate if you advise the detail of relation between IPG and VTM_IDLE_CHECK_CNT_THR

Thank you and best regards,

Michiaki

0 Vikram Sharma over 5 years ago in reply to Michiaki Tanii

TI__Genius 16030 points

Hello Michiaki,

Standard IPG = 12 and if some one is using less than 12 then we may need to change the standard count value also. This is the counter to count the symbols : "idles" in between the packets. Lesser the IPG that small is the gap between packets more difficult it is for internal Viterbi decoder (Because of latency ) to count a particular number of Idles and resetting itself before next packet.

There is no disadvantage of making it 4.

Regards,

Vikram

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DP83867CR: “VTM_IDLE_CHECK_CNT_THR” resister