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CC112X/CC1175
SWRU295C
Page 35 of 108
be asserted from the first RSSI update.
is available on a GPIO by setting
(13) or
can be read from the
Carrier Sense (CS) indication will also be affected by the setting of
After the RSSI is valid it will be continuously compared to the CS threshold set in the
register, but since the RSSI update rate is given by the
practice limit the CS update rate as well. The exception is when the CS threshold is changed while in
RX mode. The
signal will then be updated immediately (if needed). For more info
on CS, see Section 5.8.1. Figure 13 shows when CS is updated with respect to the RSSI.
Signal Strength
Time
RSSI Update
CS Threshold
RSSI
CARRIER_SENSE
Figure 13: CS vs. RSSI_UPDATE
Figure 14 shows an example of the behavior of RSSI specific signals given two different values for the
IDLE
IDLE
W
M
M
W
M
M
M
M
M
M
M
M
M
M
M
M
M
M
#8
#7
#6
#5
#4
#3
#14
#13
#12
#11
#10
#9
#15
#2
#1
#0
RX
G_MAX
G_1 < G_MAX
-128
00b
-128
10b
Carrier Sense Response Time
T0
T1
T1
T2
T2
T2
T2
T2
MARCSTATE
ACG Gain
Frontend Gain
AGC_UPDATE
Internal RSSI Estimate
AGC_STABLE_GAIN
AGC_HOLD
RSSI_VALID_CNT
RSSI[11:0]
RSSI_UPDATE
CARRIER_SENSE
CARRIER_SENSE_VALID
RSSI_VALID_CNT
RSSI[11:0]
RSSI_UPDATE
CARRIER_SENSE
CARRIER_SENSE_VALID
Time Intervals
Time
T2
Figure 14: RSSI/CS Timing Diagram
T0:
Start-up delay before RSSI measurements can begin. This delay is dependent on demodulator
settings and can be found using Table 20, Table 21, and Equation 15.