MRF24J40_08 Datasheet, PDF (111/152 Pages) Microchip Technology – IEEE 802.15.4™ 2.4 GHz RF Transceiver

MRF24J40
3.12.3 TX BEACON FIFO
In Beacon-Enabled mode, the TX Beacon FIFO is used
for the transmission of beacon frames during the
beacon slot of the superframe.
In Nonbeacon-Enabled mode, the TX Beacon FIFO is
used for the transmission of a beacon frame at the time
it is triggered (transmitted).
FIGURE 3-13:
TX BEACON FIFO FORMAT
octets
Packet Structure
1
1
Header Frame
Length Length
(m) (m + n)
m
Header
To transmit a packet in the TX Beacon FIFO, perform
the following steps:
1. The host processor loads the TX Beacon FIFO
with an IEEE 802.15.4 compliant beacon frame
using the format shown in Figure 3-13.
n
Payload
TX Beacon FIFO
Memory Address
0x080 0x081 0x082 – (0x082 + m – 1)
(0x082 + m) – (0x082 + m + n – 1)
2. If the beacon frame is to be encrypted, the
security enabled bit in the frame control field
should be set to ‘1’ in the MAC Header (MHR)
when the host microcontroller loads the TX
Beacon FIFO, and set the TXBSECEN
(TXBCON 0x1A<1>) bit = 1. Refer to
Section 3.17 “Security” for more information
about Security modes.
3. Transmit the packet by setting the TXBTRIG
(TXBCON 0x1A<0>) bit = 1. The bit will be auto-
matically cleared by hardware. If the MRF24J40
is configured for Beacon-Enabled mode, the
beacon frame will be transmitted at the beacon
slot time at the beginning of the superframe. In
Nonbeacon-Enabled mode, the beacon frame is
transmitted at the time of triggering.
© 2008 Microchip Technology Inc.
Preliminary
DS39776B-page 109