PIC24FJ64GA705 Datasheet, PDF (269/412 Pages) –

PIC24FJ256GA705 FAMILY
FIGURE 21-2:
ALARM MASK SETTINGS
Alarm Mask Setting
(AMASK<3:0>)
0000 - Every half second
0001 - Every second
Day of
the
Week Month
Day
0010 - Every 10 seconds
0011 - Every minute
0100 - Every 10 minutes
0101 - Every hour
0110 - Every day
0111 - Every week
d
1000 - Every month
dd
1001 - Every year⁽¹⁾
mm
dd
Note 1: Annually, except when configured for February 29.
Hours Minutes Seconds
s
ss
m
ss
mm
ss
hh
mm
ss
hh
mm
ss
hh
mm
ss
hh
mm
ss
21.6 Power Control
The RTCC includes a power control feature that allows
the device to periodically wake-up an external device,
wait for the device to be stable before sampling wake-up
events from that device and then shut down the external
device. This can be done completely autonomously by
the RTCC, without the need to wake-up from the current
lower power mode.
To use this feature:
1. Enable the RTCC (RTCEN = 1).
2. Set the PWCEN bit (RTCCON1L<10>).
3. Configure the RTCC pin to drive the PWC control
signal (RTCOE = 1 and OUTSEL<2:0> = 011).
The polarity of the PWC control signal may be chosen
using the PWCPOL bit (RTCCON1L<9>). An active-
low or active-high signal may be used with the
appropriate external switch to turn on or off the power
to one or more external devices. The active-low setting
may also be used in conjunction with an open-drain
setting on the RTCC pin, in order to drive the ground
pin(s) of the external device directly (with the appropri-
ate external VDD pull-up device), without the need for
external switches. Finally, the CHIME bit should be set
to enable the PWC periodicity.
Once the RTCC and PWC are enabled and running, the
PWC logic will generate a control output and a sample
gate output. The control output is driven out on the
RTCC pin (when RTCOE = 1 and OUTSEL<2:0> = 011)
and is used to power up or down the device, as
described above.
Once the control output is asserted, the stability win-
dow begins, in which the external device is given
enough time to power up and provide a stable output.
Once the output is stable, the RTCC provides a sample
gate during the sample window. The use of this sample
gate depends on the external device being used, but
typically, it is used to mask out one or more wake-up
signals from the external device.
Finally, both the stability and the sample windows close
after the expiration of the sample window and the
external device is powered down.
 2016 Microchip Technology Inc.
DS30010118B-page 269