Specifications

CC1101
SWRS061I Page 54 of 98
RCCTRL0 and RCCTRL1 respectively. If the
RC oscillator calibration is turned off, it will
have to be manually turned on again if
temperature and supply voltage changes.
Refer to Application Note AN047 [4] for further
details.
19.6 Timing
19.6.1 Overall State Transition Times
The main radio controller needs to wait in
certain states in order to make sure that the
internal analog/digital parts have settled down
and are ready to operate in the new states. A
number of factors are important for the state
transition times:
 The crystal oscillator frequency, f
xosc
 PA ramping enabled or not
 The data rate in cases where PA ramping
is enabled
 The value of the TEST0, TEST1, and
FSCAL3 registers
Table 34 shows timing in crystal clock cycles
for key state transitions.
Power on time and XOSC start-up times are
variable, but within the limits stated in Table
13.
Note that TX to IDLE and TX to RX transition
times are functions of data rate (f
baudrate
). When
PA ramping is enabled (i.e.
FREND0.PA_POWER≠000
b
), TX to IDLE and
TX to RX will require
(FREND0.PA_POWER)/8∙f
baudrate
longer times
than the times stated in Table 34.
Description
Transition Time
(no PA ramping)
Transition Time [µs]
IDLE to RX, no calibration
1953/f
xosc
75.1
IDLE to RX, with calibration
1953/f
xosc
+ FS calibration Time
799
IDLE to TX/FSTXON, no calibration
1954/f
xosc
75.2
IDLE to TX/FSTXON, with calibration
1953/f
xosc
+ FS calibration Time
799
TX to RX switch
782/f
xosc
+ 0.25/f
baudrate
31.1
RX to TX switch
782/f
xosc
30.1
TX to IDLE, no calibration
~0.25/f
baudrate
~1
TX to IDLE, with calibration
~0.25/f
baudrate
+ FS calibration Time
725
RX to IDLE, no calibration
2/f
xosc
~0.1
RX to IDLE, with calibration
2/f
xosc
+ FS calibration Time
724
Manual calibration
283/f
xosc
+ FS calibration Time
735
Table 34: Overall State Transition Times (Example for 26 MHz crystal oscillator, 250 kBaud data
rate, and TEST0 = 0x0B (maximum calibration time)).
19.6.2 Frequency Synthesizer Calibration
Time
Table 35 summarizes the frequency
synthesizer (FS) calibration times for possible
settings of TEST0 and
FSCAL3.CHP_CURR_CAL_EN. Setting
FSCAL3.CHP_CURR_CAL_EN to 00
b
disables
the charge pump calibration stage. TEST0 is
set to the values recommended by SmartRF
Studio software [5]. The possible values for
TEST0 when operating with different frequency
bands are 0x09 and 0x0B. SmartRF Studio
software [5] always sets
FSCAL3.CHP_CURR_CAL_EN to 10
b
.
Note that in a frequency hopping spread
spectrum or a multi-channel protocol the
calibration time can be reduced from 712/724
µs to 145/157 µs. This is explained in Section
28.2.