CC1110Fx / CC1111Fx
12.8 Sleep Timer
The Sleep Timer is used to control when the
CC1110Fx/CC1111Fx exits from PM{0 - 2} and
hence the Sleep Timer can be used to
implement a wake up functionality which
enables CC1110Fx/CC1111Fx to periodically wake
up to active mode and listen for incoming RF
packets.
given
by
WOREVT1.EVENT0
and
WOREVT0.EVENT0, and an exponent value set
by WORCTRL.WOR_RES. When using the low
power RC oscillator to clock the Sleep Timer,
tEvent0 is given by:
750
tEvent0
EVENT0 25WOR _ RES
fref
Note: The Sleep timer should not be used
in active mode
If the 32.768 kHz crystal oscillator is used to
clock the Sleep Timer, tEvent0 is calculated as
follows:
12.8.1
Sleep Timer Operation
1
tEvent0
EVENT0 25WOR _ RES
This section describes the operation of the
timer.
32768
The time from the CC1110Fx/CC1111Fx enters
PM2 until the next Event 0 is programmed to
appear (tSLEEPmin) should be larger than 11.08
ms when fref is 26 MHz and 12 ms when fref is
24 MHz (Sleep Timer clocked by the low
power RC oscillator).
Note: In this section of the document, fRef is
used to denote the reference frequency for
the synthesizer.
For CC1110Fx
and for
fref
fXOSC
fXOSC
CC1111Fx,
fref
2
750
tSLEEP
384
When referring to the low power RCOSC,
calibrated values are assumed
min
fref
When the Sleep Timer is clocked by the
The Sleep Timer consists of a 31-bit counter.
The appropriate bits of this counter are
selected according to a resolution setting
determined by the WORCTRL.WOR_RES
register bits. The Sleep Timer is either clocked
by the 32.768 kHz crystal oscillator or by the
low power RC oscillator (fref / 750). The timer
can only be used in PM0, PM1, and PM2.
32.768 kHz crystal oscillator, tSLEEP = 11.72
min
ms (384/32768).
12.8.2
Sleep Timer and Power Modes
Entering PM{0 - 2} and/or updating EVENT0
and has to be aligned to a positive edge on the
32 kHz clock source. The following code
examples should be used in order to update
EVENT0and/or entering PM{0 - 2} correctly:
The Sleep Timer has a programmable timing
event called Event 0. While in PM0, PM1, or
PM2, reaching Event
CC1110Fx/CC1111Fx enter active mode.
0
will make the
Please note that the update rate of the
WORTIME0 register will depend on the Sleep
The time between two consecutive Event 0’s
Timer
resolution,
configured
through
(tEvent0) is programmed with a mantissa value
WORCTRL.WOR_RES.
SWRS033H
Page 126 of 246
TI [ TEXAS INSTRUMENTS ]
