Rainbow Electronics AT86RF230 - Manual (Page 16)

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AT86RF230
5131A-ZIGB-06/14/06
5. Extended Operating Modes
The AT86RF230 transceiver implements address filtering, automatic acknowledgement frame generation and
automatic frame retransmission for peer-to-peer networks in compliance with the IEEE 802.15.4 standard.
Automatic modes help to achieve low power consumption and low peak current: TX-ARET (transmit/auto-retry) and
RX-AACK (receive/auto-acknowledge).
A TX-ARET transaction consists of:
• CSMA/CA
• Frame transmission (if the channel is available) and automatic CRC generation
• Reception of ACK frame (if required by frame type and ACK request)
• Retry of CSMA/CA if the channel is busy or an ACK is expected but not received
• Interrupt signaling at the end of the transaction, with exit code (success, channel busy, no ACK)
A RX-AACK frame reception consists of:
• Frame reception and automatic CRC check
• Address filtering
• Interrupt signaling that the frame was received (if it passes address filtering)
• Automatic ACK frame transmission (if the received frame passed the address filter and if an ACK is
required by the frame type and ACK request)
A state diagram including these extended operating modes is shown in Figure 5-1.
5.1. Peer-to-peer Network Support
The automatic modes of the AT86RF230 are designed for peer-to-peer networks and non-slotted operation, as
defined in the IEEE 802.15.4 standard.
Note that automatic CRC generation can only be applied in conjunction with the TX-ARET mode, and automatic
CRC check will only be applied in RX-AACK mode.
In RX-AACK mode, an ACK frame will always be sent with the data-pending bit set to zero. In TX-ARET mode, an
ACK is considered to be valid if the CRC is valid, and if the sequence number of the ACK corresponds to the
previously transmitted frame. The value of the “data-pending” bit is ignored.
Important Note: ACK frames will not be automatically generated for frames with either the broadcast PAN ID
(0xFFFF) or a broadcast address.