Subject: Re: [PATCH v3 3/3] ptp: Added a clock that uses the eTSEC found on the MPC85xx.

From: Scott Wood <[email-masked]>
Date: Tue, 18 May 2010 11:23:38 -0500

On 05/18/2010 01:36 AM, Richard Cochran wrote:
> On Mon, May 17, 2010 at 01:05:54PM -0500, Scott Wood wrote:
>>>>>> +  - tmr_fiper1   Fixed interval period pulse generator.
>>>>>> +  - tmr_fiper2   Fixed interval period pulse generator.
>>>>
>>
>> MPC8572 and P2020 have fiper3 as well.
>
> I doubt they really have a third fiper.
>
> First of all, this signal is not routed anywhere on the boards.

OK, but that's a separate issue from whether it exists on the chip and 
could be used on a different board.

> Also, according to the documentation, it has no bit in the TMR_CTRL or the
> TMR_TEMASK registers.

It does seem inconsistent -- but could just be bad docs.

> Unless there is a bit in TMR_TEMASK, you cannot
> get an interrupt from it.
>
> If you cannot use the signal externally (in the "real" world) and you
> cannot get an interrupt, what good is it to have such a periodic
> signal? Polling the bit in the TMR_TEVENT to see when a pulse occurs
> seems pointless.
>
> Scott, you have connections, right? Can you clarify this for me?

I'll ask around.

-Scott