Atmega128rfa1 – Rainbow Electronics ATmega128RFA1 User Manual
Page 129
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8266A-MCU Wireless-12/09
ATmega128RFA1
9.12.46 CSMA_SEED_1 – Transceiver Acknowledgment Frame Control Register 2
Bit
7
6
NA ($16E)
AACK_FVN_MODE1
AACK_FVN_MODE0
CSMA_SEED_1
Read/Write
RW
RW
Initial Value
0
1
Bit
5
4
NA ($16E)
AACK_SET_PD
AACK_DIS_ACK
CSMA_SEED_1
Read/Write
RW
RW
Initial Value
0
0
Bit
3
2
NA ($16E)
AACK_I_AM_COORD
CSMA_SEED_12
CSMA_SEED_1
Read/Write
RW
RW
Initial Value
0
0
Bit
1
0
NA ($16E)
CSMA_SEED_11
CSMA_SEED_10
CSMA_SEED_1
Read/Write
RW
RW
Initial Value
1
0
This register is a control register for RX_AACK and contains a part of the CSMA_SEED
for the CSMA-CA algorithm.
•
Bit 7:6 – AACK_FVN_MODE1:0 - Acknowledgment Frame Filter Mode
The frame control field of the MAC header (MHR) contains a frame version subfield.
The setting of AACK_FVN_MODE specifies the frame filtering behavior of the radio
transceiver. According to the content of these register bits the radio transceiver passes
frames with a specific frame version number, number group or independent of the
frame version number. Thus the register bits AACK_FVN_MODE define the maximum
acceptable frame version. Received frames with a higher frame version number than
configured do not pass the address filter and are not acknowledged.
Table 9-69 AACK_FVN_MODE Register Bits
Register Bits
Value
Description
0
Acknowledge frames with version number 0
1
Acknowledge frames with version number 0
or 1
2
Acknowledge frames with version number 0
or 1 or 2
AACK_FVN_MODE1:0
3
Acknowledge frames independent of frame
version number
•
Bit 5 – AACK_SET_PD - Set Frame Pending Sub-field
The content of AACK_SET_PD bit is copied into the frame pending subfield of the
acknowledgment frame if the acknowledgment is the answer to a data request MAC
command frame. If in addition the bits AACK_FVN_MODE of this register are
configured to accept frames with a frame version other than 0 or 1, the content of
register bit AACK_SET_PD is also copied into the frame pending subfield of the
acknowledgment frame for any MAC command frame with a frame version of 2 or 3 that
have the security enabled subfield set to 1. This is done in the assumption that a future
version of the IEEE 802.15.4 standard might change the length or structure of the
auxiliary security header, so that it is not possible to safely detect whether the MAC
command frame is actually a data request command or not.