MRF24J40_08 Datasheet, PDF (115/152 Pages) Microchip Technology – IEEE 802.15.4™ 2.4 GHz RF Transceiver

MRF24J40
3.13.2 ACKNOWLEDGMENT REQUEST –
RECIPIENT
The MRF24J40 features hardware automatic Acknowl-
edgment. It will automatically Acknowledge a frame if
the received frame has the Acknowledgment request
subfield in the frame control field set to ‘1’. This will
maintain the RX-TX timing requirements of the
IEEE 802.15.4 Specification.
Automatic Acknowledgment is enabled by clearing the
NOACKRSP (RXMCR 0x00<5>) bit = 0. To disable
automatic Acknowledgment, set the NOACKRSP
(RXMCR 0x00<5>) bit = 1.
The transmission of an Acknowledgment frame in a
nonbeacon-enabled network, or in the CFP, shall
commence aTurnaroundTime (12) symbols after the
reception of the data or MAC command frame. The
transmission of an Acknowledgment frame in the CAP
shall commence at a backoff slot boundary. In this
case, the transmission of an Acknowledgment frame
shall commence between aTurnaroundTime and
(aTurnaroundTime + aUnitBackoffPeriod)
symbols after the reception of the data or MAC
command frame.
The IEEE 802.15.4 Specification defines
aTurnaroundTime as a constant value of 12 symbol
periods. The aTurnaroundTime can be programmed
by the TURNTIME (TXTIME 0x27<7:4>) and RFSTBL
(TXSTBL 0x2E<7:4>) bits where aTurnaroundTime =
TURNTIME + RFSTBL.
3.13.3
RECEPTION OF
ACKNOWLEDGMENT WITH FRAME
PENDING BIT
The status of the frame pending bit in the frame control
field of the received Acknowledgment frame is reflected
in the FPSTAT (TXNCON 0x1B<4>) bit.
3.13.4
TRANSMISSION OF
ACKNOWLEDGMENT WITH FRAME
PENDING BIT
The frame pending bit in the frame control field of an
Acknowledgment frame indicates that a device has
additional data to send to the recipient following the
current transfer. Refer to IEEE 802.15.4-2003
Standard, Section 7.2.1.1.3 “Frame Pending Subfield”.
Acknowledgment of a data request MAC command – In
response to a data request MAC command, if the
MRF24J40 has additional (pending) data, it can set the
frame pending bit of the Acknowledgment frame by set-
ting DRPACK (ACKTMOUT 0x12<7>) = 1. This will
only set the frame pending bit for an Acknowledgment
of a data request MAC command.
TABLE 3-17: REGISTERS ASSOCIATED WITH ACKNOWLEDGEMENT
Addr. Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
0x00 RXMCR
0x12 ACKTMOUT
0x1B TXNCON
0x1C TXG1CON
0x1D TXG2CON
0x21 TXPEND
0x24 TXSTAT
0x27 TXTIME
0x2E TXSTBL
r
r
NOACKRSP
DRPACK
MAWD6
MAWD5
r
r
r
TXG1RETRY1 TXG1RETRY0 TXG1SLOT2
TXG2RETRY1 TXG2RETRY0 TXG2SLOT2
MLIFS5
MLIFS4
MLIFS3
TXNRETRY1 TXNRETRY0 CCAFAIL
TURNTIME3 TURNTIME2 TURNTIME1
RFSTBL3
RFSTBL2
RFSTBL1
r
MAWD4
FPSTAT
TXG1SLOT1
TXG2SLOT1
MLIFS2
TXG2FNT
TURNTIME0
RFSTBL0
PANCOORD
MAWD3
INDIRECT
TXG1SLOT0
TXG2SLOT0
MLIFS1
TXG1FNT
r
MSIFS3
COORD
MAWD2
TXNACKREQ
TXG1ACKREQ
TXG2ACKREQ
MLIFS0
TXG2STAT
r
MSIFS2
ERRPKT
MAWD1
TXNSECEN
TXG1SECEN
TXG2SECEN
GTSSWITCH
TXG1STAT
r
MSIFS1
Bit 0
PROMI
MAWD0
TXNTRIG
TXG1TRIG
TXG2TRIG
FPACK
TXNSTAT
r
MSIFS0
© 2008 Microchip Technology Inc.
Preliminary
DS39776B-page 113