MRF24J40-I/ML Microchip Technology, MRF24J40-I/ML Datasheet - Page 93

• Manufacturer Part Number: MRF24J40-I/ML
• Description: IC TXRX IEEE/ZIGBEE 2.4GHZ 40QFN
• Manufacturer: Microchip Technology

Specifications of MRF24J40-I/ML

• Package / Case: 40-QFN
• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: 802.15.4
• Applications: ISM, ZigBee™
• Power - Output: 0dBm
• Sensitivity: -95dBm
• Voltage - Supply: 2.4 V ~ 3.6 V
• Current - Receiving: 18mA
• Current - Transmitting: 18mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Number Of Receivers: 1
• Number Of Transmitters: 1
• Wireless Frequency: 2.4 GHz
• Interface Type: 4 Wire SPI
• Noise Figure: 8 dB
• Output Power: + 0 dBm
• Operating Supply Voltage: 2.5 V, 3.3 V
• Maximum Operating Temperature: 85 C
• Mounting Style: SMD/SMT
• Maximum Supply Current: 22 mA
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

3.5
The CCA signal is an indication to the MAC layer from
the PHY layer as to whether the medium is busy or idle.
The MRF24J40 provides three methods of performing
CCA.
Section 6.7.9 “CCA”.
3.5.1
CCA reports a busy medium upon detecting energy
above the Energy Detection (ED) threshold.
1.
2.
3.5.2
CCA reports a busy medium only upon detection of a
signal with the modulation and spreading characteris-
tics of IEEE 802.15.4. This signal may or may not be
above the ED threshold.
1.
2.
TABLE 3-6:
© 2010 Microchip Technology Inc.
Addr.
0x3A BBREG2
0x3F CCAEDTH CCAEDTH7 CCAEDTH6 CCAEDTH5 CCAEDTH4 CCAEDTH3 CCAEDTH2 CCAEDTH1 CCAEDTH0
Program CCAMODE 0x3A<7:6> to the value, ‘10’.
Program CCAEDTH 0x3F<7:0> with CCA ED
threshold value (RSSI value).
The 8-bit CCAEDTH threshold can be mapped
to a power level according to RSSI. Refer
to Section 3.6 “Received Signal Strength
Indicator (RSSI)/Energy Detection (ED)”.
Program CCAMODE 0x3A<7:6> to the value, ‘01’.
Program CCACSTH 0x3A<5:2> with the CCA
carrier sense threshold (units).
Refer
Clear Channel Assessment (CCA)
Name
CCA MODE 1: ENERGY ABOVE
THRESHOLD
CCA MODE 2: CARRIER SENSE
ONLY
to
REGISTERS ASSOCIATED WITH CCA
CCAMODE1 CCAMODE0 CCACSTH3 CCACSTH2 CCACSTH1 CCACSTH0
IEEE
Bit 7
802.15.4-2003
Bit 6
Standard,
Bit 5
Preliminary
Bit 4
3.5.3
CCA reports a busy medium only upon detection of a
signal with modulation or spreading characteristics of
IEEE 802.15.4 with energy above the ED threshold.
1.
2.
3.
Program CCAMODE 0x3A<7:6> to the value,
‘11’.
Program CCACSTH 0x3A<5:2> with the CCA
carrier sense threshold.
Program CCAEDTH 0x3F<7:0> with the CCA
ED threshold (RSSI value).
The 8-bit CCAEDTH threshold can be mapped
to a power level according to RSSI. Refer
to Section 3.6 “Received Signal Strength
Indicator (RSSI)/Energy Detection (ED)”.
Bit 3
CCA MODE 3: CARRIER SENSE
WITH ENERGY ABOVE
THRESHOLD
Bit 2
MRF24J40
Bit 1
r
DS39776C-page 93
Bit 0
r