DP83TC814S-Q1: RGMII Input Timing Issue

Hi Wang, 

Jingkun Wang said:

Does it can increase the time of one packet?

The number of bytes per packet can be changed through register 0x61A, which may help with increasing the time. The IPG can also be increased through register 0x61B. 

Jingkun Wang said:

MAC manufacturer wants to know what test pattern is sent exactly with the setting (0x624=0x5552; 0x619=0x1005)?

In the current 0x624 = 0x5552 setting, the PHY is sending fixed data as 01010101b. This can be changed to incremental data, or random data using bits 7-6 of register 0x624. These can be adjusted to match what the MAC is expecting for the data to be coming in. 

Best,

Vivaan

Hi Vivaan,

We set the registers as below:

0x0624 = 0x00BA

0x0619 = 0x1007

The MAC registers can record the number of receiving packets.

But it cannot send a specific number of packets.

in the PRBS mode, how to set to send specific number of packets?

Best Regards!

Wang Jingkun

Hi Wang,

In PRBS, the last 3 bits, [2:0] control the number of packets being sent. Right now, you have them configured as 0x1007, which means it sends continuous packets. This value can be changed to allow a specific number of packets

Best,

Vivaan

Hi Vivaan，

The specific number of packets is in the register 0x624.

It is set in 0x00BA.

Could you have a check?

Best Regards!

Wang

Hi Wang,

You are correct, that was an oversight on my part. This configuration should be sending out 100 packets. Is this not what is recorded on the MAC side? What is the behaviour observed on the MAC? Does it read continuous packets?

Best,

Vivaan

Hi Vivaan,

The number of packets still increase in the register on the MAC.

It seems that the PHY sends the continuous packets.

Best Regards!

Wang Jingkun

Hi Wang, 

I think the register configuration of 0x619 is the cause of this behaviour.

When changing 0x619 from 0x1005 to 0x1007, you are enabling bit 1, which enables continuous PRBS packets 

Reverting back to 0x619 = 0x1005 should enable the PHY to only transfer 100 packets

Best,

Vivaan

Hi Vivaan,

When using below setting,  the MAC register can't record any packets.

phytool.sh write 0x0624 0x00BA
phytool.sh write 0x0619 0x1005

When using below setting,  the MAC register records the number of packets. But the number of packets still increase in the register on the MAC.

phytool.sh write 0x0624 0x00BA
phytool.sh write 0x0619 0x1007

Could you have a try on your EVB board.

Best Regards!

Wang Jinkgun

Hi Wang, 

I have verified the packet generation functionality on the EVM and it looks to be working as expected. I tested for 100, 1000, and 100000 packets which all worked as expected.

Is it possible for you to probe the RX lines after setting the registers as the following? I want to verify that the PHY is indeed sending packets. 

0x0624 0x00BE
0x0619 0x1005

This should enable the PHY to send 100000 packets and we can verify that the RX line is in fact active.

Best,

Vivaan