MRF24XA_15 Datasheet, PDF (159/258 Pages) Microchip Technology – Low-Power, 2.4 GHz ISM-Band IEEE 802.15.4™ RF

MRF24XA
5.6 Security Processing of Received
IEEE 802.15.4 Compliant Frames
Receive security is always performed when RXDEC is
set and awaits RXDECIF or RXTAGIF as it is not auto-
matically triggered . If both MAC and NWK layer secu-
rity are applied, then both must be processed in this
order when RXDEC is set for a second time after updat-
ing the security material correctly.
Figure 5-17 shows the security functions triggered by
RXDEC. The device automatically clears the
respective interrupts generated on completion and
RXDEC.
FIGURE 5-16:
SECURITY MATERIAL RETRIEVAL SUPPORT IN RECEIVE PROCESSING WHEN
FRMFMT = 0 (IEEE 802.15.4™ FORMAT)
Enter
MHR Parsed
0
SecEn
MAC Security
1
Parse AHR
Configure SECSUITE,
SECNONCE, SECHDRINDX,
SECPAYINDX, SECENDINDX.
For Beacon frames, the Configuration must be
overridden by SW.
Exit
After RXIF is asserted:
• SW always configures SECKEY.
• SW may need to configure SECSUITE, SECNONCE, SECHDRINDX, SECPAYINDX,
SECENDINDX.
Length is affected. MAC MAC/NWK.
Exception Handling:
FRMIF: Frame Format Error Interrupt Flag
The bit is set if the transmitter/receiver fails to parse the frame in the buffer (it is not as it must be or it is cor-
rupted in demodulation). For example, reserved values found in the MAC header fields.
 2015 Microchip Technology Inc.
Preliminary
DS70005023C-page 159