Rainbow Electronics ATmega128RFA1 - Manual (Page 54)

54
8266A-MCU Wireless-12/09
ATmega128RFA1
If AACK_FLT_RES_FT = 1 any frame with a reserved frame type is filtered by the
address filter similar to a data frame as described in the standard. Consequently, a
TRX24_AMI interrupt is generated upon address match. A TRX24_RX_END
interrupt is only generated if the address matched and the frame was not
corrupted. An acknowledgment is only send, when the ACK request subfield was
set in the received frame and a TRX24_RX_END interrupt occurred.
Note that It is not allowed to set AACK_FLTR_RES_FT = 1 and have register bit
AACK_FLTR_RES_FT set to 0.
Short Acknowledgment Frame (ACK) Start Timing
The bit AACK_ACK_TIME of register XAH_CTRL_1 defines the symbol time between
frame reception and transmission of an acknowledgment frame.
Table 9-11. Overview of RX_AACK Configuration Bits
Register Name Register Bit Description
AACK_ACK_TIME 2 0 : Standard compliant acknowledgement timing of 12
symbol periods. In slotted acknowledgement operation
mode, the acknowledgment frame transmission can be
triggered 6 symbol periods after reception of the frame
earliest.
1
: Reduced acknowledgment timing of 2 symbol periods
(32 µs).
Note that this feature can be used in all scenarios, independent of other configurations.
However, shorter acknowledgment timing is especially useful when using High Data
Rate Modes to increase battery lifetime and to improve the overall data throughput; see
"High Data Rate Modes" on page 86 for details.
9.4.2.4 Frame Filtering
Frame Filtering is an evaluation whether or not a received frame is dedicated for this
node. To accept a received frame and to generate an address match interrupt
(TRX24_AMI) a filtering procedure as described in IEEE 802.15.4-2006 chapter 7.5.6.2.
(Third level of filtering) is applied to the frame. The radio transceiver’s RX_AACK mode
accepts only frames that satisfy all of the following requirements (quote from
IEEE 802.15.4-2006, 7.5.6.2):
1. The Frame Type subfield shall not contain a reserved frame type.
2. The Frame Version subfield shall not contain a reserved value.
3. If a destination PAN identifier is included in the frame, it shall match macPANId or
shall be the broadcast PAN identifier (0xFFFF).
4. If a short destination address is included in the frame, it shall match either
macShortAddress or the broadcast address (0xFFFF). Otherwise, if an extended
destination address is included in the frame, it shall match aExtendedAddress.
5. If the frame type indicates that the frame is a beacon frame, the source PAN
identifier shall match macPANId unless macPANId is equal to 0xFFFF, in which
case the beacon frame shall be accepted regardless of the source PAN identifier.
6. 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.
The radio transceiver requires two additional rules:
1. The frame type indicates that the frame is not an ACK frame (refer to Table 9-6 on
page 50).