The pps of Dp83640 disappear when there is a large negative change.

Kevin_KDP

Intellectual 260 points

Other Parts Discussed in Thread: DP83640

Hi,

I use dp83640 for ptp time adjust.

When there is a large negative change, the PPS is disappeared.

I see these words in Sofrware Development Guide 3.1.4.6

If a large adjustment to the PTP time is made, the PPS trigger may need to be rearmed to avoid a long
period of inactivity or a period of rapid pulsing. For a large positive change in time (greater than one
second), the trigger should be rearmed to trigger at a second boundary relative to the new time, prior to
making the time adjustment. For a large negative change, the trigger should be disabled prior to making
the time adjustment, and then rearmed after making the time adjustment.

When there is a large negative change, I diable the trigger by TRIG_DIS, but after adjustment, the pps is still disappeared when i rearmed the trigger.

Is there any advise?

Thank you,

Kevin

over 9 years ago

0 Kevin_KDP over 9 years ago

Intellectual 260 points

Hi,

I found that there is a error with my config of trigger config as follows:

sec = 2;
nsec = 0UL;
pwidth = 1 * 2000000000UL;
pwidth += 0;
pwidth /= 2;

/*load trigger*/
val |= TRIG_LOAD;

DP83640_WriteReg(PhyAddr, PAGE4, PTP_CTL, val);

DP83640_WriteReg(PhyAddr, PAGE4, PTP_TDR, nsec & 0xffff); /* ns[15:0] */

DP83640_WriteReg(PhyAddr, PAGE4, PTP_TDR, nsec >> 16); /* ns[31:16] */

...

I config the expireTimeSeconds as a fixed value .

How to confirm the expireTimeSeconds ?

Kevin

0 Kevin_KDP over 9 years ago in reply to Kevin_KDP

Intellectual 260 points

Hi,

Now I read the current tdr time(+2), for the expireTimeSeconds . I don't know if it's a good idea...

Kevin

0 Rob Rodrigues over 9 years ago in reply to Kevin_KDP

TI__Mastermind 19780 points

Hi Kevin,

Did your first suggested configuration fix the issue with the pps signal disappearing?

What is the status of your configuration problem now?

Best Regards,

0 Kevin_KDP over 9 years ago in reply to Rob Rodrigues

Intellectual 260 points

Hi Rob,

My problem is when there is a large negative adjustment to the PTP time is made, we should rearm the trigger. when we rearm the

trigger,what value should be config to expireTimeSeconds ? Is it must be a value bigger than current ptp time?

Best Regards,

Kevin

0 Rob Rodrigues over 9 years ago in reply to Kevin_KDP

TI__Mastermind 19780 points

Hi Kevin,

Yes, this is correct. For large negative jumps, greater than 1 second, you should disable trigger, correct the time, then rearm the trigger.

The trigger expire time should be bigger than current ptp time.

Best Regards,

Interface

Interface forum

The pps of Dp83640 disappear when there is a large negative change.