MRF24XA_15 Datasheet, PDF (127/258 Pages) Microchip Technology – Low-Power, 2.4 GHz ISM-Band IEEE 802.15.4™ RF

MRF24XA
4.14 Acknowledge Sending by
Recipient
ACK sending must never use CSMA whether AUTO-
ACKEN = 1 or 0.
A TXIF is not generated when an ACK packet
completes transmission. However, TXSFDIF and
TXMAIF are set.
FIGURE 4-14:
AUTOMATIC ACKNOWLEDGE SENDING (AUTOACKEN = 1 AND ACKREQ = 1)
Enter
RXEN = 1
FrameCtrl.AckReq = 1
must hold for entry
Receiver turned OFF,
transmitter remains ON
(Default) RXChannel = TXChannel = CH<3:0>.
For the exception, refer to Section 7.1 “Channel Agility”
on agility.
FRMFMT = 1
Yes
Proprietary frame carrying AckInfo.
No
Await RXACKWAIT Base time units. (start
transition to TX just in time)
Start transmitting the preamble in the frame
(without doing CSMA)
(when SFD is sent: TXSFDIF
1)
Generate ACKNOWLEDGE frame MHR
without writing to buffer. If FRMFMT = 0 then
FrameCtrl.FramePend
ACKTXFP.
SEQUENCE received frame sequence
0
ADPTCHEN
1
Use AckInfo field of the received
frame to select the transmitting
channel for the ACK frame
0
ADPTDREN
1
Use AckInfo field of the received
frame to select the transmitting
data rate for the ACK frame
Append FCS (on-the-fly)
CH<3:0> selected as receive channel
Return to RX
Exit
 2015 Microchip Technology Inc.
Preliminary
DS70005023C-page 127