CC2400_07 Datasheet, PDF (35/83 Pages) Texas Instruments – 2.4 GHz Low-Power RF Transceiver

CC2400
RX=TX=1
SXOSCOFF
OFF
[0]
SXOSCON &
Osc. settled
IDLE
[1]
SRX | STX | SFSON
RX=TX=0 |
RX=TX=1
PIN
RXTX_CAL
[8]
All calib done &
fs in lock
RX=0
PIN
FS_ON
[9]
TX=0
RX=TX=0
RX=TX=0 |
RX=TX=1
STROBE
RXTX_CAL
[14]
All calib done &
fs in lock
SFSON
STROBE
FS_ON
[15]
SFSON | packet done
STX
SRX
PIN
PIN
TX
RX
[12]
[10]
TX=0 |
RX=1 | packet done
TX=1 |
RX=0 | packet done
PIN
TX_OFF
[13]
PIN
RX_OFF
[11]
STROBE
TX
[17]
SRFOFF|
SFSON | packet
done
STROBE
TX_OFF
[18]
Immediately
STROBE
RX
[16]
BEFORE_IDLE
[24]
SRFOFF
Figure 15. Radio control state diagram (FSMSTATE.FSM_CUR_STATE[4:0] value in
brackets)
Figure 15 shows a state transition diagram
for the radio control state machine. This
figure shows the possibilities that exist for
changing between states. Note for
example that it is not possible to go from
IDLE mode back to OFF. This diagram
can be very useful for debugging what is
happening within the CC2400 by reading
FSMSTATE.FSM_CUR_STATE[4:0].
If invalid parameters are used during
development or testing, the PLL may not
lock after calibration. If this happens, the
CC2400 will get stuck in the
STROBE_RXTX_CAL state. The chip
must then be reset to exit this state. This
should never happen in an actual
application as long as recommended
register settings are used.
Also note that the frequency register
FSDIV should only be modified when the
CC2400 is in IDLE mode, otherwise the
PLL may go out of lock since calibration is
only performed when exiting the IDLE
state
SWRS042A
Page 35 of 83