CC2430 Datasheet, PDF (159/212 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

Data received over RF
Address
recognition OK
SFD
FIFO
FIFOP , if threshold
higher than frame length
FIFOP , if threshold
lower than frame length
Data received over RF
Address
recognition fails
SFD
FIFO
FIFOP
Preamble
CC2430
Radio : Transmit mode
SFD ^{detecteLdength byte received}
Adcdoremspsleretegdocnition
SFD Length
MAC Protocol Data Unit (MPDU) with correct address
LasbtyMtePrDecUeived
Preamble
SFD Length
MAC Protocol Data Unit (MPDU) with wrong address
Figure 35: SFD, FIFO and FIFOP activity examples during receive
Figure 36: Example of status activity when reading RXFIFO.
14.9 Transmit mode
During transmit the RFSTATUS.FIFO and
RFSTATUS.FIFOP bits are still only related to
the RXFIFO. The RFSTATUS.SFD bit is
however active during transmission of a data
frame,
as
shown
in
Figure 37.
The RFIF.IRQ_SFD interrupt flag goes high
and the RF interrupt is requested when the
SFD field has been completely transmitted. It
goes low again when the complete MPDU (as
defined by the length field) has been
transmitted or if an underflow is detected. The
interrupt RFERR is then asserted if enabled.
See section 14.17.1 on page 163 for more
information on TXFIFO underflow.
As can be seen from comparing Figure 35 and
Figure 37, the RFSTATUS.SFD bit behaves
very similarly during reception and
transmission of a data frame. If the
RFSTATUS.SFD bits of the transmitter and the
receiver are compared during the transmission
of a data frame, a small delay between 3.076
µs and 3.284 µs can be seen because of
bandwidth limitations in both the transmitter
and the receiver.
CC2430 Data Sheet (rev. 2.1) SWRS036F
Page 159 of 211