CC1111F16RSPR View Datasheet(PDF) - TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS
Part Name
Description
MFG CO.
CC1111F16RSPR
TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS
'CC1111F16RSPR' PDF : 240 Pages View PDF
CC1110Fx / CC1111Fx
• High speed RC oscillator (12 – 13.5
MHz for CC1110Fx and 12 MHz for
CC1111Fx)
The high speed crystal oscillator startup time
may be too long for some applications, and the
device can therefore run on the high speed
RCOSC until the crystal oscillator is stable.
The HS RCOSC consumes less power than
the crystal oscillator, but since it is not as
accurate as the crystal oscillator it can not be
used for RF transceiver operation.
The CLKCON.OSC bit selects the source of the
system clock (high speed crystal oscillator, HS
XOSC, or high speed RC oscillator, HS
RCOSC). The system clock will not change
clock source before the selected clock source
is stable (indicated by SLEEP.XOSC_STB and
SLEEP.HFRC_STB). It should be noted that
once the clock source change has been
initiated the clock source should not be
changed or updated until clock actually has
been set as source.
The oscillator not selected as the system clock
source, will be set in power-down mode by
setting SLEEP.OSC_PD to 1 (the default state).
Please note the minimum requirement on high
speed crystal oscillator powerdown time in all
modes of operation for CC1110Fx, see Table 11.
The HS RCOSC may be turned off when the
high speed crystal oscillator has been selected
as system clock source and vice versa. When
SLEEP.OSC_PD is 0, both oscillators are
powered up and running. Be aware that
SLEEP.OSC_PD is cleared if the CLKCON.OSC
bit is toggled.
When the high speed crystal oscillator is
selected as system clock source
(CLKCON.OSC is set to 0), the HS RCOSC will
be calibrated once. If SLEEP.OSC_PD=0, the
HS RCOSC will run on the calibrated value
once the calibration is completed (see Table
15 for initial calibration time). If
SLEEP.OSC_PD=1, the HS RCOSC will be
turned off after calibration, but the calibration
value will be stored and used when the HS
RCOSC is started again. In order to calibrate
the HS RCOSC regularly (if so found
necessary based on the drift parameters listed
in Table 15) one should switch between using
the HS RCOSC and the high speed crystal
oscillator as system clock source.
If CLKCON.OSC is set to 0 when entering
PM{1-3}, the HS RCOSC will be calibrated
once when returning to active mode.
13.1.5.2 System clock speed and radio
When the radio is to be used the system must
run on HS XOSC. The RF part will be
unaffected by the CLKCON.CLKSPD setting.
There is however parts of the RF core that
runs on the system clock affected by and this
will cause limitations in manageable data rates
in RF link. These limitations are summarized in
Table 49 below. Note that these numbers does
not apply for FEC usage. Using FEC requires
CLKCON.CLKSPD to be 000.
CLKCON.
CLKSPD
Maximum datarate, kBaud
MSK
GFSK,
OOK and
ASK
2FSK
000
500
250
500
001
500
250
500
010
500
250
500
011
500
250
500
100
400
250
400
101
200
200
200
110
100
100
100
111
50
50
50
Table 49: System clock speed VS data rate
13.1.5.3 Low Speed Oscillators (32 kHz clock
source)
Two low speed oscillators are present in the
device:
• Low speed crystal oscillator (32.768
kHz)
• Low power RC oscillator (32 – 36 kHz
for CC1110Fx and 32 kHz for CC1111Fx)
The low speed crystal oscillator is designed to
operate at 32.768 kHz and provide a stable
clock signal for systems requiring time
accuracy. The low power RC oscillator run at
fXOSC / 750 for CC1110Fx and fXOSC / 1500 for
CC1111Fx, when calibrated. The calibration can
only take place when the high speed crystal
oscillator is enabled and stable. The low power
RC oscillator should be used to reduce cost
and power consumption compared to the
32.768 kHz crystal oscillator solution. The two
low speed oscillators can not be operated
simultaneously.
By default, after a reset, the low power RC
oscillator is enabled and selected as the 32
kHz clock source. The RC oscillator consumes
less power, but is less accurate than the
32.768 kHz crystal oscillator. Refer to section
SWRS033E
Page 81 of 239
Share Link: 