IEEE1588 with QorIQ

[evgenyr]

Hello,

Does someone have experience with IEEE1588 on QorIQ platform, its P1010/P1011 RDB (refernce design board) or some different RDB ?

It should be a master ,what kind of accuracy is conceivable on this board?

Thanks

[evgenyr]

Besides exchanging the ptp messages which is keeping local network synchronised to 1588 master clock,

I need periodically to verify/synchronize the 1588 timer according the internal system clock (for example RTC)

which is getting the precise time from GPS.  

My question is if Reference design has some mechanism which is doing it ? How long it takes?

Can it affect the general accuracy?

Thanks in advance

Evgeny

[bpe]

You can adjust the on-chip dedicated timer based on any source of synchronization. The overall accuracy does not

directly depend on it.

As if the reference designs,  there are no dedicated interfaces to connect a GPS receiver. Some boards

have an connector that carries external clock inputs for the timer and external event timestamp trigger

inputs.

Have a great day,
Platon

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[lunminliang]

Hello Evgeny Raskin,

As pbe wrote, the accuracy highly dependent on the software implementation. And the overall accuracy also depends on input clock accuracy.

Purely software implementation has much lower accuracy. With hardware assist, the accuracy improves.The Ethernet controller in PowerQUICC and QorIQ devices contains dedicated hardware for registering time-stamps of both incoming and outgoing Ethernet packets, which enables nanoseconds synchronization of clocks.

There is an application note talks about this, AN3423 Support for IEEE 1588™ Protocol in PowerQUICC and QorIQ Processors, it's available from:

http://cache.freescale.com/files/32bit/doc/app_note/AN3423.pdf

Have a great day,
Lunmin

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[evgenyr]

Platon and Lunmin thank you very much for your detailed information and the link.

In some of the Freescale document mentioned the IEEE1588 IXXAT protocol stack.

My project is the time server for small local network and my question is if on PowerQUICC, QorIQ or i.MX6 platforms

the IEEE1588 IXXAT protocol stack or free linuxptpt protocol is in use?

Is there some advantage to use IXXAT protocol?

Thanks

[bpe]

Both IXXAT network clock implementation and ptpd are supported by

Freescale QorIQ SDK. As of the advantages of IXXAT, it is commercial

software, with all advantages and disadvantages coming from that fact:

you have to pay for it, but you receive support. Contact IXXAT directly

(www.ixxat.com) for more information about what they offer.

Have a great day,
Platon

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[evgenyr]

So, what is running on the Freescale's reference design, IXXAT or Linuxptp?

If there is a option to run some evaluation version of IXXAT?

Thanks

Evgeny

[bpe]

The hardware resolution is determined by the 1588 clock period used in

a design. For example, if TSEC1_TX_CLK is used as 1588 clock source

then resolution can't be better than it's period (25MHz -> 40ns).

The final resolution is determined by the 1588 software stack.

Our experience of implementation of IEEE 1588 on PowerQUICC II Pro

with IXXAT protocol stack provided RMS resolution ~ 6 clock periods

between two cards back-to-back. This should be the same for QorIQ

series processors as IEEE 1588 dedicated hardware in them is mostly

identical to PoweQUICC.

Have a great day,
Platon

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