AT86RF232 Atmel Corporation, AT86RF232 Datasheet - Page 93

• Manufacturer Part Number: AT86RF232
• Manufacturer: Atmel Corporation

Specifications of AT86RF232

• Max. Operating Frequency: 0 MHz
• Crypto Engine: AES
• Operating Voltage (vcc): 1.8 to 3.6
• Frequency Band: 2.4 GHz
• Max Data Rate (mb/s): 0.25
• Antenna Diversity: Yes
• External Pa Control: Yes
• Power Output (dbm): 3
• Receiver Sensitivity (dbm): -100
• Receive Current Consumption (ma): 11.8
• Transmit Current Consumption (ma): 13.8
• Link Budget (dbm): 103

8.5 Clear Channel Assessment (CCA)
8.5.1 Overview
8.5.2 Configuration and Request
8321A–MCU Wireless–10/11
The main features of the Clear Channel Assessment (CCA) module are:
 All four modes are available as defined by IEEE 802.15.4-2006 in Section 6.9.9
 Adjustable threshold for energy detection algorithm
A CCA measurement is used to detect a clear channel. Four modes are specified by
IEEE 802.15.4-2006:
Table 8-10. CCA Mode Overview.
The CCA modes are configurable via register 0x08 (PHY_CC_CCA).
Using the Basic Operating Mode, a CCA request can be initiated manually by setting
CCA_REQUEST = 1 (register 0x08, PHY_CC_CCA), if the Atmel AT86RF232 is in any
RX state. The current channel status (CCA_STATUS) and the CCA completion status
(CCA_DONE) are accessible in register 0x01 (TRX_STATUS).
The CCA evaluation is done over eight symbol periods and the result is accessible
t
request), refer to
indicated by an interrupt IRQ_4 (CCA_ED_DONE).
The register bits CCA_ED_THRES of register 0x09 (CCA_THRES) defines the received
power threshold of the “Energy above threshold” algorithm. The threshold is calculated
by RSSI
interpreted as a busy channel.
CCA
Note:
CCA Mode
= 180µs (max.) (128µs measurement duration and processing delay) after the
0, 3
1
2
BASE_VAL
1.
It is not recommended to manually initiate a CCA measurement when using the
Extended Operating Mode.
Description
Energy above threshold.
CCA shall report a busy medium upon detecting any energy above the ED
threshold.
Carrier sense only.
CCA shall report a busy medium only upon the detection of a signal with the
modulation and spreading characteristics of an IEEE 802.15.4 compliant signal.
The signal strength may be above or below the ED threshold.
Carrier sense with energy above threshold.
CCA shall report a busy medium using a logical combination of
-
-
Where the logical operator may be configured as either OR (mode 0) or
AND (mode 3).
+ 2 x CCA_ED_THRES [dB]. Any received power above this level is
Detection of a signal with the modulation and spreading characteristics of
this standard and
Energy above the ED threshold.
Table
7-2. The end of a manually initiated CCA measurement is
AT86RF232
93