CC2510FX Datasheet, PDF (210/253 Pages) List of Unclassifed Manufacturers – True System-on-Chip with Low Power RF Transceiver and 8051 MCU

CC2510Fx / CC2511Fx
• Calibrate every fourth time when going
from either RX or TX to IDLE
The calibration takes a constant number of
XOSC cycles (see Table 66 for timing details).
When RX is activated, the chip will remain in
receive mode until the RX termination timer
expires (see section 15.12.3) or a packet has
been successfully received. 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 15.10. After a packet is
successfully received the radio controller will
then go to the state indicated by the
MCSM1.RXOFF_MODE setting. The possible
states are:
• IDLE
• 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.
The CPU can change the state from RX to TX
and vice versa by using the command strobes.
If the radio controller is currently in transmit
and the SRX strobe is written, 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 issued, the
“TX if clear channel” function will be used. If
the channel is not clear, the chip will remain in
RX. The MCSM1.CCA_MODE setting controls
the conditions for clear channel assessment.
See section 15.10.7 on page 206 for details.
The SIDLE command strobe can always be
issued to force the radio controller to go to the
IDLE state.
15.12.2 Timing
The radio controller controls most timing in
CC2510Fx/CC2511Fx, such as synthesizer
calibration, PLL lock and RT/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. Table 66 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 9.
Note that in a frequency hopping spread
spectrum or a multi-channel protocol the
calibration time can be reduced from 721 µs to
approximately 150 µs. This is explained in
section 15.18.2.
Description
Idle to RX, no calibration
Idle to RX, with calibration
Idle to TX/FSTXON, no calibration
Idle to TX/FSTXON, with calibration
TX to RX switch
RX to TX switch
RX or TX to IDLE, no calibration
RX or TX to IDLE, with calibration
Manual calibration
XOSC
periods
2298
~21037
2298
~21037
560
250
2
~18739
~18739
26MHz
crystal
88.4µs
809µs
88.4µs
809µs
21.5µs
9.6µs
0.1µs
721µs
721µs
Table 66: State transition timing
15.12.3 RX Termination Timer
CC2510Fx/CC2511Fx has optional functions for
automatic termination of RX after a
programmable time. The termination timer
starts when enabling the demodulator. The
timeout is programmable with the
MCSM2.RX_TIME setting. When the timer
expires, the radio controller will check the
condition for staying in RX; if the condition is
not met, RX will terminate. After the timeout,
the condition will be checked continuously.
The programmable conditions are:
• MCSM2.RX_TIME_QUAL=0:
Continue
receive if sync word has been found
• MCSM2.RX_TIME_QUAL=1:
Continue
receive if sync word has been found or
preamble quality is above threshold (PQT)
If the system can expect the transmission to
have started when enabling the receiver, the
MCSM2.RX_TIME_RSSI function can be used.
The radio controller will then terminate RX if
the first valid carrier sense sample indicates no
carrier (RSSI below threshold). See Section
CC2510Fx/CC2511Fx PRELIMINARY Data Sheet (Rev. 1.2) SWRS055A Page 210 of 252