Atmega128rfa1 – Rainbow Electronics ATmega128RFA1 User Manual
Page 52
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8266A-MCU Wireless-12/09
ATmega128RFA1
Register Name
Register Bits
Description
AACK_FVN_MODE
7:6
Controls the ACK behavior, depends on FCF frame
version number
0x00
: acknowledges only frames with version
number 0, i.e. according to IEEE 802.15.4-2003
frames
0x01
: acknowledges only frames with version
number 0 or 1, i.e. frames according to
IEEE 802.15.4-2006
0x10
: acknowledges only frames with version
number 0 or 1 or 2
0x11
: acknowledges all frames, independent of the
FCF frame version number
Second level of filtering according to IEEE 802.15.4-2006, section 7.5.6.2, is applied to
a received frame if the radio transceiver is in promiscuous mode. However, a
TRX24_RX_END interrupt is issued even if the FCS is invalid. Thus it is necessary to
read bit RX_CRC_VALID of register PHY_RSSI after the TRX24_RX_END interrupt in
order to verify the reception of a frame with a valid FCS.
If a device, operating in promiscuous mode, receives a frame with a valid FCS which in
addition passed the third level filtering according to IEEE 802.15.4-2006, section
7.5.6.2, an acknowledgement frame would be transmitted. According to the definition of
the promiscuous mode a received frame shall not be acknowledged even if it is
requested. Thus bit AACK_DIS_ACK of register CSMA_SEED_1 has to be set to 1.
In all receive modes a TRX24_AMI interrupt is issued, when the received frame
matches the node’s address according to the filter rules described in section
Alternatively, in RX_ON state of the Basic Operating Mode when a valid PHR is
detected a TRX24_RX_START interrupt is generated and the frame is received. The
end of the frame reception is signalized with a TRX24_RX_END interrupt. At the same
time the bit RX_CRC_VALID of register PHY_RSSI is updated with the result of the
FCS check (see
).
The RX_CRC_VALID bit must be checked in
order to dismiss corrupted frames according to the definition of the promiscuous mode.
9.4.2.3.3 Configuration of non IEEE 802.15.4 Compliant Scenarios
Sniffer
shows a RX_AACK configuration to setup a sniffer device. Other
RX_AACK configuration bits should be set to their reset values (see
49). All frames received are indicated by a TRX24_RX_START and TRX24_RX_END
interrupt. Bit RX_CRC_VALID of register PHY_RSSI is updated after frame reception
with the result of the FCS check (see
).
The RX_CRC_VALID bit
needs to be checked in order to dismiss corrupted frames.
Table 9-9. Configuration of a Sniffer Device
Register Name
Register Bits
Description
AACK_PROM_MODE
1
1
: Enable promiscuous mode
AACK_DIS_ACK
4
1
: Disable generation of acknowledgment
This operating mode is similar to the promiscuous mode.