XStream™OEMRFModule–ProductManualv5.x00[2006.02.24]
4.3. Acknowledged Communications
4.3.1. Acknowledged Mode
Characteristics: Reliable delivery through positive acknowledgements for each packet
Throughput, latency and jitter vary depending on the quality of the channel
and the strength of the signal.
Recommended Use: Acknowledge Mode configuration is appropriate when reliable delivery is
required between modules. If messages are smaller than 256 bytes, use RB and RO commands
to align RF packets with application packets.
Required Parameter Values (TX Module): RR (Retries) >= 1
Related Commands: Networking (DT, MK, RR), Serial Interfacing (PK, RN, TT, RO, RB)
Table4‐04. SampleNetworkProfile
Module Parameter Settings (assume default values for parameters not listed)
All
ATRR A [set number of Retries to 0x0A]
ATRN 5 [set number of Delay Slots to 5]
Acknowledged Mode Connection Sequence
Figure4‐06. AcknowledgedModeStateDiagramÆ
After sending a packet while
in Acknowledged Mode, the
transmitting module listens f
an ACK (ack
it receives the ACK, it will
either send a subsequent
packet (if more transmit data
is pending), or will wai
exactly RN random delay
before allowing another
transmission (if no more
is pending for transmission).
If the transmitting module
or
nowledgement). If
t for
slots
data
l
d
ns
N is
t
have
nnot return to RF transmit (or retransmit) mode as long as it is
receiving RF data.
does not receive the ACK
within the allotted time, it wil
retransmit the packet with a
new RF initializer following the
ACK slot. There is no delay
between the first ACK slot an
the first retransmission.
Subsequent retransmissio
incur a delay of a random
number of delay slots,
between 0 and RN. If R
set to 0 on the transmitting
module, there are never any
back-off delays between
retransmissions. Note tha
during back-off delays, the
transmitting module will go
into Idle Mode and may
receive RF data. This can
the effect of increasing the
back-off delay, as the radio ca
©2006MaxStream,Inc.ConfidentialandProprietary 41
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