DP83640: IEEE1588v2PTP ; time synchronization message.

Hi Alon,

Thank you for your reply.
I will post answers to your questions here after I confirm them with my customer.
Your continued support will be greatly appreciated.

Best regards,
Kanae

Hi Alon,

Regarding Q2, I confirmed the details with the customer as follows.

What I wanted to ask was, in order to perform time synchronization with PTP,
I send and receive time synchronization messages at regular intervals between master and slave,
but is it possible to send other data in addition to these messages?
Is it possible to send and receive other data in addition to the time synchronization messages?

In addition, please let us know if there are any documents that can be used as references or
if there are any details that can be understood regarding the following.

1. Regarding time synchronization messages, how much time occupancy should we estimate?
　I think it depends on the setting, but I would like to have some data for reference.

2. How much does sending data other than time messages affect the synchronization accuracy?

3. How much data other than synchronization messages can be transferred by the combination of AM6548 and DP83640?

The following is my understanding of "time synchronization messages".

(1) In SNLA098A (AN-1728 IEEE 1588 Precision Time Protocol Time Synchronization Performance),
there is a table of Test Conditions, where IEEE 1588 PTP Synchronization Interval: 1 second.
　I assume that a time synchronization message ( packets of IEEE 1588) is sent and received
between the master and the slave every 1 second.

(2) For the time synchronization messages, see Figure 1, Basic PTP Timing Diagram in SNLA116A (AN-1963 IEEE 1588 Synchronization Over Standard Networks Using the DP83640).
Timing Diagram, I think that Sync and Delay_Req, etc. occur every second between the master and
the slave when IEEE 1588 PTP Synchronization Interval: 1 second is set in (1).
　
These "packets" such as Sync and Delay_Req are called "time synchronization messages"
are called "time synchronization messages".

If you need other details, please let me know.

Best regards,
Kanae

Hi Alon,

Thank you for your reply.

I am sorry that the question is not clear.

The following Renesas microcontrollers: RX64M, etc., support the IEEE1588 function for Ethernet communication,
which can be used to generate the 51.2KHz, 102.4KHz, 204.8KHz, 409.6KHz, and 819.2KHz signals required for sensor control.

My customer would like to confirm whether this functionality can be realized with the AM6548 and DP83640.

Sensor Synchronization
As shown in the figure below, the above signals can be synchronously output using PLD in a daisy chain configuration
with one grandmaster (GM) at each end, one slave (SO) at the other end, and two boundary clocks (BC) in the middle.

Each microcontroller is connected to each other via 100 Mbps Ethernet, so sensor control data and sensing data can be transferred.
The PC control shown in the figure above can be used to collect and analyze the highly accurate time-synchronized sensing data
collected by each microcontroller on the PC.
The daisy chain configuration is expected to be applied to various sensor networks.

When using DP83640, the signals at 51.2KHz, 102.4KHz, 204.8KHz, 409.6KHz, and 819.2KHz
are supposed to be changed to PPS (Pulse-Per-Second).

As shown in the figure below, it we would be like synchronizing the main units (1) to (4) with PTP
while also communicating data between the main units (1) to (4).

Question:
Is it possible to send other data other than synchronization messages (packets) with AM6548 and DP83640?

Please let us know if there are any unclear points.

Bets regards,
Kanae

Hi Alon,

Thank you for your reply and I shared it with my customer.

From the reply we received, my customer wants to use the time synchronization packets only to synchronize the nodes
and to send and receive data packets separately from the time synchronization packets.
In other words, customer is of the opinion that data packets are different from time synchronization packets and
therefore do not need to be synchronized.

My customer thinks that the IEEE1588v2 function can be used to synchronize the clocks of each device
while communicating between devices (data transfer over a LAN), and that this is achieved by the previous explanation
I posted about the function of Renesas microcontrollers: RX64M and other microcontrollers.

Is it not possible to realize the above functionality that the customer is considering using a combination of AM6548 and DP83640?
If not, customer will look for another method or another company's product, if you have any idea to realize it with TI products, please suggest.

Note that Dante (YAMAHA) for audio can also be synchronized with PTP and data communication (audio signals) can also be executed,
so as a customer, it is hoped that there is some way to achieve this.

Best regards,
Kanae

Hi Alon,

Thank you for your reply.
I will share it with the customer that it is the nodes that are synchronized, not all packets,
but if two nodes synchronize their clocks, it is possible to have PTP on all packets.

Alon said:
It is possible. With this combination, it should not matter if 1588V2 is enabled or not."

Please allow me to confirm your answer.
The "the above functionality" that I mentioned in the above post refers to the configuration shown in the figure below, which I posted earlier.

As shown in the figure below, it we would be like synchronizing the main units (1) to (4) with PTP
while also communicating data between the main units (1) to (4).

Since the customer wants to use the high-precision system synchronization function of IEEE-1588 Precision Time Protocol (PTP) to achieve this,
I do not understand the intent of your answer (there should be no problem even if 1588V2 is not enabled).

How do you actually realize the high precision system synchronization function of PTP with the combination of AM6548 and DP83640
without 1588V2 enabled?

Best regards,
Kanae

Hi Alon,

Thank you for your reply.

I will simplify my question.
Is it correct to understand that the combination of AM6548 and DP83640 can be used to realize
the high precision system synchronization function of PTP by enabling IEEE1588v2 (PTP)
on each device, since the datasheet states as below?

AM6548:.
- One Gigabit Ethernet (CPSW) interface supporting
- RMII (10/100) or RGMII (10/100/1000)
- IEEE1588 (2008 Annex D, Annex E, Annex F)
with 802.1AS PTP

DP83640:
- IEEE 1588 V1 and V2 Supported

Best regards,
Kanae

Hi Alon,

Thank you for your reply.
I understand that on the Ethernet side, it is possible to achieve this with DP83640.
As for AM6548, I will check with the MCU team on the Processor forum.

Best regards,
Kanae