CC1110Fx / CC1111Fx
When RX is activated, the chip will remain in
receive mode until a packet is successfully
received or the RX termination timer expires
(see Section 14.12.3). Note: the probability
that a false sync word is detected can be
reduced by using PQT, CS, maximum sync
word length, and sync word qualifier mode as
describe in Section 14.10.1. After a packet is
successfully received the radio controller will
then go to the state indicated by the
MCSM1.RXOFF_MODE setting. The possible
destinations are:
function the register TEST1 on page 222
should be set to 0x31. If the channel is not
clear, the chip will remain in RX. For more
details on clear channel assessment see
Section 14.10.7 on page 198 for details.
The SIDLE command strobe can always be
used to force the radio controller to go to the
IDLE state.
14.12.2 Timing
The radio controller controls most timing in
CC1110Fx/CC1111Fx,
such
as
synthesizer
• IDLE
calibration, PLL lock time and RX/TX
turnaround times. Timing from IDLE to RX and
IDLE to TX is constant, dependent on the auto
calibration setting. RX/TX and TX/RX
turnaround times are constant. The calibration
time is constant 18739 clock periods (fRef).
Table 72 shows the timing for key state
transitions.
• FSTXON: Frequency synthesizer on and
ready at the TX frequency. Activate TX
with STX.
• TX: Start sending preambles
• RX: Start search for a new packet
Similarly, when TX is active the chip will
remain in the TX state until the current packet
has been successfully transmitted. Then the
state will change as indicated by the
MCSM1.TXOFF_MODE setting. The possible
destinations are the same as for RX.
Power on time and XOSC start-up times are
variable, but within the limits stated in Table 11
and Table 12
Note that in a frequency hopping spread
spectrum or a multi-channel protocol it is
possible to reduce the calibration time from
721 µs to approximately 150 µs. This is
explained in Section 14.18.2.
It is possible to change the state from RX to
TX and vice versa by using the command
strobes. If the radio controller is currently in
transmit and an SRX strobe is written to the
RFST register, the current transmission will be
ended and the transition to RX will be done.
If the radio controller is in RX when the STX or
SFSTXON command strobes are used and
MCSM1.CCA_MODE
≠
00, the TX-if-CCA
function will be used. Note that for TX-if-CCA
Transition Time
Description
fRef Periods
2298
fRef = 26 MHz fRef = 24 MHz
Idle to RX, no calibration
Idle to RX, with calibration
88.4 µs
809 µs
88.4 µs
95.8 µs
876.5 µs
95.8 µs
~21037
2298
Idle to TX/FSTXON, no
calibration
Idle to TX/FSTXON, with
calibration
~21037
809 µs
876.5 µs
TX to RX switch
560
250
2
21.5 µs
9.6 µs
0.1 µs
721 µs
721 µs
23.3 µs
10.4 µs
0.1 µs
RX to TX switch
RX or TX to IDLE, no calibration
RX or TX to IDLE, with calibration ~18739
Manual calibration ~18739
780.8 µs
780.8 µs
Table 72: State Transition Timing
SWRS033E
Page 202 of 239
TAOS [ TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS ]
