CC2420 Datasheet, PDF (32/87 Pages) List of Unclassifed Manufacturers – 2.4 GHz IEEE 802.15.4 / ZigBee-ready RF Transceiver

SmartRF ^® CC2420
SFLUSHRX command strobe should be
issued twice to ensure that the SFD pin
goes back to its idle state.
For security enabled frames, the MAC
layer must read the source address of the
received frame before it can decide which
key to use to decrypt or authenticate. This
data must therefore not be overwritten
even if it has been read out of the RXFIFO
by the microcontroller. If the
SECCTRL0.RXFIFO_PROTECTION control
bit is set, CC2420 also protects the frame
header of security enabled frames until
decryption has been performed. If no MAC
security is used or if it is implemented
outside the CC2420, this bit may be cleared
to achieve optimal use of the RXFIFO.
Data received over RF
Address
recognition OK
SFD Pin
FIFO Pin
FIFOP Pin, if threshold
higher than frame length
FIFOP Pin, if threshold
lower than frame length
Preamble
SFD ^{detecteLdength byte received}
Adcdoremspsleretegdocnition
SFD Length
MAC Protocol Data Unit (MPDU) with correct address
LasbtyMtePrDecUeived
Data received over RF
Address
recognition fails
SFD Pin
FIFO Pin
FIFOP Pin
Preamble
SFD Length
MAC Protocol Data Unit (MPDU) with wrong address
Figure 12. Pin activity examples during receive
SCLK
SFD
CSn
SI
SO
FIFOP
FIFO
ADDR_TXFIFO
-
Status
Length
-
PSDU0
-
PSDU1
FIFaOsPbloyrnteegmsaa>sinFnsIuFhmOigbPhe_rToHf ^R
-
PSDU2
-
PSDU3
-
PSDU4
-
PSDU5
FIFrOeasgdtoaoerutsst ^{olofwlaswthbeynte}
-
RSSI
-
FCS/Corr
Figure 13. Example of pin activity when reading RXFIFO.
Chipcon AS SmartRF^® CC2420 Preliminary Datasheet (rev 1.2), 2004-06-09
Page 32 of 87