MC13224V Datasheet, PDF (12/48 Pages) Freescale Semiconductor, Inc – Advanced ZigBee™- Compliant Platform-in-Package (PiP) for the 2.4 GHz IEEE® 802.15.4 Standard

delimiter). During receive, the modem will recognize preamble and SFD, then the MACA will begin
receiving the packet with the first bit of frame length, and finally, will check the FCS.
Sequencer
Timers
Control
Registers
To
Transceiver
Modem
TX Packet
Buffer
RX Packet
Buffer
FCS Generator/
Checker
DMA
MACA
To
MCU
Bus
Figure 5. MAC Accelerator Simplified Block Diagram
NOTE
The radio can receive packets of either mode without prior indication of the
incoming packet mode.
2.7.1.1 MACA Features
In order to reduce CPU load, the MACA module has embedded features for controlling parts of the IEEE
802.15.4 PHY and MAC layer requirements. The MACA core features include:
• Sequence Manager sequences / auto sequences
— RX only
— TX only
— Automatic acknowledgment frame reception on transmitted packets
— Automatic acknowledgment frame transmission on received packets
— Auto-RX for continuous reception as coordinator
— Auto sequence for transmitted MAC data.request
— Assist for efficient response to MAC data.request
— Embedded channel assessment in sequence
— Support for sequences with slotted mode access
— Timer triggered and immediately executed actions
— Support for extended RX for reception in random backoff and battery life extension
— Support for promiscuous mode
• Programmable auto sequence timing - Each CCA, RX, or TX event is an independent operation.
The radio gets through a power-up or “warm-up” sequence for each operation (including VCO),
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