Re: MPC555 RTC Question

The USIU manual states:

The RTCAL is a 32-bit read/write register. When the value of the RTC is 
equal to the
value programmed in the alarm register, a maskable interrupt is generated.

What do you initialize it to? Also, do you clear SEC before enabling the 
RTC?

trailrunner23 wrote:

>Wondering if anyone can explain something a little odd about the RTC.
>I've got the RTC and PIT initialized to generate interrupts once per
>second, and the DEC to generate interrupts once per millisecond. The
>first RTC interrupt occurs as soon as I enable interrupts, but the
>first PIT interrupt occurs very close to one second later. It doesn't
>help if I explicitly acknowledge a (possibly pending) RTC interrupt
>before enabling the interrupt. Anybody understand this? I want to
>think of the RTC as the number of seconds that have elapsed since
>boot, but it's always ahead by one second.
>
>Thanks,
>
>Joe
>
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-- 
David Wybo                    mailto:[email protected]
RealTime Consultants, Inc.    Phone: 248.345.6160
www.realtimeconsultantsinc.com





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