Rainbow Electronics AT86RF231 - Manual (Page 75)

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8111A–AVR–05/08
AT86RF231
length or structure of the auxiliary security header, so it is not possible to safely detect whether
the MAC command frame is actually a data request command or not.
• Bit 4 - AACK_ DIS_ACK
If this bit is set no acknowledgment frames are transmitted in RX_AACK Extended Operating
Mode, even if requested.
• Bit 3 - AACK_I_AM_COORD
This register bit has to be set if the node is a PAN coordinator. It is used for address filtering in
RX_AACK.
If AACK_I_AM_COORD = 1 and if only source addressing fields are included in a data or MAC
command frame, the frame shall be accepted only if the device is the PAN coordinator and the
source PAN identifier matches macPANId, for details refer to IEEE 802.15.4, section 7.5.6.2
(third-level filter rule 6).
• Bit [2:0] - CSMA_SEED_1
These register bits are the higher 3-bit of the CSMA_SEED, bits [10:8]. The lower part is in reg-
ister 0x2D (CSMA_SEED_0), see register CSMA_SEED_0 for details.
Register 0x2F (CSMA_BE):
• Bit [7:4] - MAX_BE
Register bits MAX_BE defines the maximum back-off exponent used in the CSMA-CA algorithm
to generate a pseudo random number for back off the CCA. For details refer to IEEE 802.15.4-
2006, Section 7.5.1.4.
Valid values are [4'd8, 4'd7, … , 4'd3].
• Bit [3:0] - MIN_BE
Register bits MIN_BE defines the minimum back-off exponent used in the CSMA-CA algorithm
to generate a pseudo random number for back off the CCA. For details refer to IEEE 802.15.4-
2006, Section 7.5.1.4.
Valid values are [MAX_BE, (MAX_BE - 1), … , 4'd0].
Note
• If MIN_BE = 0 and MAX_BE = 0 the CCA back off period is always set to 0.
Bit 7 6 5 4 3 2 1 0
+0x2F MAX_BE MIN_BE CSMA_BE
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Reset Value 0 1 0 1 0 0 1 1