MRF24XA_15 Datasheet, PDF (136/258 Pages) Microchip Technology – Low-Power, 2.4 GHz ISM-Band IEEE 802.15.4™ RF

MRF24XA
FIGURE 5-4:
EXAMPLE: PACKET MODE WITH NKW-LAYER SECURITY
Legend:
Data Flow direction
Initiator
Event or Control Flow
Responder
Sending Node
Receiving Node
TX Host
MCU
SPI, INT
TX
Device
Medium
Construct
1 frame
Unprocessed Frame (FR)
TXBUFEMPTY=0
2
TX Configuration
RX
Device
SPI, INT
RX Host
MCU
RX Configuration
1
Key, Nonce, Indices
3
4
5
Check PRFR-optional
6
7
Set TXENC
TXENCIF=1, TXENC=0
Read TX buffer
TX security processing
Processed Frame (PRFR)
Set TXST
TXSFDIF=1
TXIF=1, TXBUFEMPTY=1
Frame Sending
Frame Started on Air
SHR (SFD) finished
Buffer is written to if no RXOVFIF
Frame Complete
RX Frame Filter
If RXBUFFULL=1 when
RXSFDIF=1 then
RXOVFIF=1 and drops packet
RXSFDIF=1
2
RXFLTIF=1 or RXIF=1
Read RX buffer
Key, Nonce, Indices
Set RXDEC
3
4
Check PRFR
Retrieve Key,...
4
5
RX security processing
RXDECIF=1 or
RXTAGIF=1
6
Read RX buffer
Check FR
DS70005023C-page 136
Preliminary
 2015 Microchip Technology Inc.