CC2420 Chipcon AS, CC2420 Datasheet - Page 63

• Manufacturer Part Number: CC2420
• Description: 2.4 GHz RF Transceiver for IEEE 802.15.4 and ZigBee
• Manufacturer: Chipcon AS

MDMCTRL1 (0x12)– Modem Control Register 1
15:11
10:6
5
4
3:2
1:0
RSSI (0x13) - RSSI and CCA Status and Control Register
15:8
7:0
Chipcon AS SmartRF ® CC2420 Preliminary Datasheet (rev 1.0), 2003-11-17
Bit
Bit
Field Name
-
CORR_THR[4:0]
DEMOD_AVG_MODE
MODULATION_MODE
TX_MODE[1:0]
RX_MODE[1:0]
Field Name
CCA_THR[7:0]
RSSI_VAL[7:0]
Reset
0
0
0
0
0
0
Reset
-32
-128
R/W
W0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
SmartRF
Description
Reserved, write as 0.
Demodulator correlator threshold value, required before SFD
search. Should always be set to 20.
Frequency offset average filter behaviour.
0 : Lock frequency offset filter after preamble match
1 : Continuously update frequency offset filter.
Set one of two RF modulation modes for RX / TX
0 : IEEE 802.15.4 compliant mode
1 : Reversed phase, non-IEEE compliant (could be used to set
up a system which will not receive 802.15.4 packets)
Set test modes for TX
0 : Buffered mode, use TXFIFO (normal operation)
1 : Serial mode, use transmit data on serial interface, infinite
transmission. For lab testing only.
2 : TXFIFO looping ignore underflow in TXFIFO and read cyclic,
infinite transmission. For lab testing only.
3 : Send random data from CRC, infinite transmission. For lab
testing only.
Set test mode of RX
0 : Buffered mode, use RXFIFO (normal operation)
1 : Receive serial mode, output received data on pins. Infinite
RX. For lab testing only.
2 : RXFIFO looping ignore overflow in RXFIFO and write cyclic,
infinite reception. For lab testing only.
3 : Reserved
Description
Clear Channel Assessment threshold value, signed number on
2’s complement for comparison with the RSSI.
The unit is 1 dB, offset is the same as for RSSI_VAL . The CCA
signal goes high when the received signal is below this value.
The CCA signal is available on the CCA pin.
The reset value is approximately -77 dBm.
RSSI estimate on a logarithmic scale, signed number on 2’s
complement.
Unit is 1 dB, offset is described in the RSSI / Energy Detection
section on page 45.
The RSSI_VAL value is averaged over 8 symbol periods. The
RSSI_VALID status bit may be checked to verify that the
receiver has been enabled for at least 8 symbol periods.
The reset value of –128 also indicates that the RSSI_VAL value
is invalid.
®
CC2420
Page 63 of 85