PRU SYNC0 output

David Cemin

Other Parts Discussed in Thread: SYSBIOS

Hi,

When using the PRU for PTP applications, sync0 provides a 1Hz-1KHz clock synchronized to PTP. Would it be possible to have this output on Sync1 instead?

Thank you

David

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Please post what processor and what software you are asking about.

0 David Cemin over 9 years ago in reply to Biser Gatchev-XID

Intellectual 400 points

Sitara processors

For instance AM3558 or AM572x.

Reference: processors.wiki.ti.com/.../ICSS_PTP_1588_Developer_Guide

0 Biser Gatchev-XID over 9 years ago in reply to David Cemin

TI__Guru**** 393215 points

Thanks. The PRU experts have been notified. They will respond here, but please note that a delay is possible due to holidays in the USA.

0 Garrett Ding over 9 years ago in reply to Biser Gatchev-XID

TI__Mastermind 43296 points

David,

1PPS output can only come out of Sync0 at the moment. It’s hard-coded in the firmware.

Regards, Garrett

0 David Cemin over 9 years ago in reply to Garrett Ding

Intellectual 400 points

Hi Garret,

I understand that it is hardcoded in the firmware, but the question is: Can I change this hardcoded value to go to sync1 (since Beaglebone Black is only outputing sync1 instead of sync0) ? If yes, can you point me to the directions on how to recompile this and load it to the PRU ?

Thank you

regards,

David

0 Garrett Ding over 9 years ago in reply to David Cemin

TI__Mastermind 43296 points

David,

There is no source code of PRU for industrial SDK released. Only the binaries of the PRU are provided as header files in the Industrial SDK package. Therefore, you really can't change the hardcoded signal from sync0 to sync1. Also, industrial SDK software is only supported on ICE board for AM335x.

Regards, Garrett

0 David Cemin over 9 years ago in reply to Garrett Ding

Intellectual 400 points

Thank you Garret,

how is the support for this on the AM572x board (www.ti.com/.../TMDSEVM572X) ?

regards ,

David

0 Garrett Ding over 9 years ago in reply to David Cemin

TI__Mastermind 43296 points

David,

Industrial SDK (PRU SYNC0) is supported on AM572x IDK board: .

Regards,

Garrett

0 David Cemin over 9 years ago in reply to Garrett Ding

Intellectual 400 points

Thank you Garret,

I think I just have one more question: Can I change the frequency of the sync0 output to higher values than 1kHz? If yes, how high this frequency can go ?

Thank you

David

0 Garrett Ding over 9 years ago in reply to David Cemin

TI__Mastermind 43296 points

David

1PPS signal is generated by Sync unit inside the IEP which is based on Compare1 event. The sync interval can be from 1ms to 1s, i.e., 1Hz to 1KHz by design. You can experiment the sync0 output (PTP_SYNC0_CYCLE_COUNT) with the following code snippet:

C:\ti\sysbios_ind_sdk_02.01.02.02\sdk\protocols\ptp\include\icss_ptp_time.h
   #define PTP_SYNC0_CYCLE_COUNT       1000000

C:\ti\sysbios_ind_sdk_02.01.02.02\sdk\protocols\ptp\drivers\icss_ptp_time.c
    /*Program compare 1 event value*/
    ptpObjPtr->pulseInterval = PTP_ONE_SEC_NS_COUNT;
    iep_reg_val = PTP_SYNC0_CYCLE_COUNT;
    HWREG(emacBaseAddr->prussIepRegs + HW_ICSS_IEP_CMP1) = iep_reg_val;

Regards,
Garrett

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PRU SYNC0 output