Rainbow Electronics AT86RF231 User Manual
Page 98
98
8111A–AVR–05/08
AT86RF231
r e g i s t e r b i t i s a u t o m a t i c a l l y c l e a r e d a f t e r r e q u e s t i n g a C C A m e a s u r e m e n t w i t h
CCA_REQUEST = 1.
• Bit [6:5] - CCA_MODE
The CCA mode can be selected using register bits CCA_MODE.
Note that IEEE 802.15.4-2006 CCA Mode 3 defines the logical combination of CCA Mode 1 and
2 with the logical operators AND or OR. This can be selected with:
• Bit [4:0] - CHANNEL
Section 9.7 “Frequency Synthesizer (PLL)” on page 121
Register 0x09 (CCA_THRES):
This register sets the ED threshold level for CCA.
• Bit [7:5] - Reserved
• Bit [4:0] - CCA_ED_THRES
The CCA Mode 1 request indicates a busy channel if the measured received power is above
RSSI_BASE_VAL + 2 * CCA_ED_THRES [dBm]. CCA Modes 0 and 3 are logical related to this
result.
Table 8-12.
CCA Status Result
Register Bit
Value
State Description
CCA_MODE
0
Mode 3a, Carrier sense OR energy above threshold
1
Mode 1, Energy above threshold
2
Mode 2, Carrier sense only
3
Mode 3b, Carrier sense AND energy above threshold
• CCA_MODE = 0
for logical operation OR, and
• CCA_MODE = 3
for logical operation AND.
Bit
7
6
5
4
3
2
1
0
+0x09
Reserved
CCA_ED_THRES
CCA_THRES
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
1
1
0
0
0
1
1
1