AT86RF233 Datasheet, PDF (45/196 Pages) ATMEL Corporation – Low Power, 2.4GHz Transceiver for ZigBee, RF4CE, IEEE 802.15.4, 6LoWPAN, and ISM Applications

AT86RF233
7.2 Extended Operating Mode
Extended Operating Mode makes up for a large set of automated functionality add-ons
which can be referred to as a hardware MAC accelerator. These add-ons go beyond
the basic radio transceiver functionality provided by the Basic Operating Mode.
Extended Operating Mode functions handle time critical MAC tasks, requested by the
IEEE 802.15.4 standard, in hardware, such as automatic acknowledgement, automatic
CSMA-CA, and retransmission. This results in a more efficient IEEE 802.15.4 software
MAC implementation, including reduced code size, and may allow use of a smaller
microcontroller or operation at low clock rates.
The Extended Operating Mode is designed to support IEEE 802.15.4-2006 and
IEEE 802.15.4-2011 compliant frames; the mode is backward compatible to
IEEE 802.15.4-2003 and supports non IEEE 802.15.4 compliant frames. This mode
comprises the following procedures:
Automatic acknowledgement (RX_AACK) divides into the tasks:
 Frame reception and automatic FCS check
 Configurable addressing fields check
 Interrupt indicating address match
 Interrupt indicating frame reception, if it passes address filtering and FCS check
 Automatic ACK frame transmission (if the received frame passed the address filter
and FCS check and if an ACK is required by the frame type and ACK request)
 Support of slotted acknowledgment using SLP_TR pin (used for beacon-enabled
operation)
Automatic CSMA-CA and Retransmission (TX_ARET) divides into the tasks:
 CSMA-CA, including automatic CCA retry and random backoff
 Frame transmission and automatic FCS field generation
 Reception of ACK frame (if an ACK was requested)
 Automatic retry of transmissions if ACK was expected but not received or accepted
 Interrupt signaling with transaction status
Automatic FCS check and generation, refer to Section 8.2, is used by the RX_AACK
and TX_ARET modes. In RX_AACK mode, an automatic FCS check is always
performed for incoming frames.
In TX_ARET mode, an ACK, received within the time required by IEEE 802.15.4, is
accepted if the FCS is valid, and if the sequence number of the ACK matches the
sequence number of the previously transmitted frame. Dependent on the value of the
frame pending subfield in the received acknowledgement frame the transaction status is
set, see TRAC_STATUS, Section 7.2.7.
An Atmel AT86RF233 state diagram, including the Extended Operating Mode states is
shown in Figure 7-11. Orange marked states represent the Basic Operating Mode; blue
marked states represent the Extended Operating Mode.
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