MRF49XA Datasheet, PDF (60/102 Pages) Microchip Technology – ISM Band Sub-GHz RF Transceiver

MRF49XA
TABLE 3-2: DIGITAL RSSI THRESHOLD LEVELS
RSSI Threshold
DRSSIT2
Reserved
1
Reserved
1
-73
1
-79
1
-85
0
-91
0
-97
0
-103
0
DRSSIT1
1
1
0
0
1
1
0
0
FIGURE 3-11:
INPUT POWER VS. ANALOG RSSI VOLTAGE
-112
-102
-9 2
-82
-72
-62
-52
Input Power (dBm)
DRSSIT0
1
0
1
0
1
0
1
0
1.2
1
0.8
0.6
0.4
0.2
0
-42
3.13.1 RELATIONSHIP BETWEEN RSSI
AND CLOCK RECOVERY
The DIO signal response time setting is configured
through RXCREG and has the following modes of
operation:
• Normal Mode
• Slow Mode
• Medium Mode
• Fast Mode
These operation modes are configurable through
BBFCREG.
In Medium mode, the DIO signal is active when the
CR_LOCK and the DRSSI or the DQI signals are high.
The data indicator output goes low when either the
CR_LOCK turns inactive, or the DRSSI or DQI signals
go low. For more details on DQI, see Section 3.11
“Data Quality Indicator”.
3.13.2 RELATIONSHIP BETWEEN RSSI
AND AFC
The Keep Offset mode of automatic configuration of
AFC (i.e., AUTOMS1 = 1, AUTOMS0 = 1) is recom-
mended to be used when a receiver operates with only
one transmitter. After a complete measuring cycle, the
measured value is kept independent from the state of
the DIO signal. In this mode, the DRSSI limit should be
carefully selected to minimize the range hysteresis.
The registers associated with RSSI are:
• STSREG (see Register 2-1)
• GENCREG (see Register 2-2)
• RXCREG (see Register 2-7)
• PMCREG (see Register 2-13)
DS70590B-page 58
Preliminary
© 2009 Microchip Technology Inc.