MRF24XA_15 Datasheet, PDF (153/258 Pages) Microchip Technology – Low-Power, 2.4 GHz ISM-Band IEEE 802.15.4™ RF

MRF24XA
REGISTER 5-3:
R-0
r
bit 7
SECHDRINDX (SECURITY HEADER INDEX REGISTER)
R/W/HS-0000000
SECHDRINDX<6:0>
ADDRESS: 0x2B
bit 0
Legend: R = Readable bit W = Writable bit
-n = Value at POR
‘1’ = Bit is set
r = Reserved
HS = Hardware Set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7
bit 6-0
Reserved: Maintain as ‘0’
SECHDRINDX<6:0>: Security Header Index bits
This field defines the portion of the header which performs the authentication operations.
For MAC layer security, SECHDRINDX<6:0> is defined as the address offset of the MAC header from
the beginning of the frame, as stored in the buffer (0 = Length field, 1 = FrameCtrl field, and so on), and
is automatically loaded for both 802.15.4 and Proprietary frames.
For Network layer security, SECHDRINDX<6:0> is defined as the address offset of the Network Header
from the beginning of the MAC Payload, and the Host Controller loads it only for 802.15.4 frames. Note
that for Proprietary frames, the MAC automatically loads it⁽¹⁾.
Note 1: The setting DTSM in TX mode disables automatic computation of this field.
REGISTER 5-4:
R-0
r
bit 7
SECPAYINDX (SECURITY PAYLOAD INDEX REGISTER)
R/W/HS-0000000
SECPAYINDX<6:0>
ADDRESS: 0x2C
bit 0
Legend: R = Readable bit W = Writable bit
-n = Value at POR
‘1’ = Bit is set
r = Reserved
HS = Hardware Set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7
bit 6-0
Reserved: Maintain as ‘0’
SECPAYINDX<6:0>: Security Payload Index bits
This field defines the portion of the payload which performs the Encryption/Decryption operations.
For MAC layer security, SECPAYINDX<6:0> is defined as the address offset of the MAC Payload from
the beginning of the frame, as stored in the buffer (0 = Length field, 1 = FrameCtrl field, and so on), and
is automatically loaded for both 802.15.4 and Proprietary frames.
For Network layer security, SECPAYINDX<6:0> is defined as the address offset of the Network Header
from the beginning of the MAC Payload, and the Host Controller loads it only for 802.15.4 frames. Note
that for Proprietary frames, the MAC automatically loads it⁽¹⁾.
Note 1: The setting DTSM in TX mode disables automatic computation of this field.
 2015 Microchip Technology Inc.
Preliminary
DS70005023C-page 153