MRF24XA_15 Datasheet, PDF (124/258 Pages) Microchip Technology – Low-Power, 2.4 GHz ISM-Band IEEE 802.15.4™ RF

MRF24XA
REGISTER 4-15:
bit 7
BOUNIT (BACK-OFF TIME UNIT REGISTER)
R/W-10100000
BOUNIT<7:0>
ADDRESS: 0x1B
bit 0
Legend: R = Readable bit W = Writable bit
-n = Value at POR
‘1’ = Bit is set
r = Reserved
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7-0
BOUNIT<7:0>: CSMA-CA Back-off Period Unit Field bits
The number of Base time units for the basic back-off time unit used by CSMA-CA algorithm.
11111111 = 256 Base time units
•
•
•
00000000 = 1 Base time unit
FIGURE 4-12:
CSMA-CA ALGORITHM
NB = 0
BE = MINBE <3:0>
Delay for a Random number of Back-off
Periods between 0 and 2^^BE -1
Perform CCA
Yes
Channel Idle?
No
NB = NB +1
BE = min (BE + 1, MAXBE <3:0>)
Yes
NB > BOMCNT <2:0>?
No
(Failure)
Transmit Pending Packet
(Success)
DS70005023C-page 124
Preliminary
 2015 Microchip Technology Inc.