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DNT900 - 08/16/10
RF_DataRate - this sets the over-the-air data rate. DNT900’s with different RF data rates cannot inter-
communicate. The following codes are defined:
0x00 = 500 kb/s (default)
0x01 = 200 kb/s
0x02 = 115.2 kb/s
0x03 = 38.4 kb/s
0xff = auto
The auto setting will cause a remote to try all four over-the-air rates when scanning for a network to join.
Setting the RF_DataRate to a fixed value on the remotes will allow a network to link much faster than
using the auto setting. However, if the base RF_DataRate is changed when the remotes are set to a fixed
rate, the network will not link. Note that changing this setting does not take effect immediately. It must be
followed by a MemorySave command (See Section 4.2.9) and then a hardware reset.
HopDuration - this sets the duration of the hop frame. The duration is set as a 12-bit value,
0.05 ms/count. Changing the hop duration must be followed by a MemorySave command to allow the
change to persist through a reset or power cycle. A HopDuration change takes effect immediately. Re-
motes will re-link following a HopDuration parameter change.
InitialParentNwkID - this parameter selects the network ID that a base will use to start a network, or a
remote will be allowed to join. A value of 0xFF instructs a remote to operate in 'promiscuous mode' and
join any network it finds (if set for a base, this will select the default network ID of 0x00.)
In a tree-routing system, this parameter controls which parent a child router or remote can join. Setting
this value to 0x00 forces a router or a remote to join with only the base. Setting this parameter to the
NwkID of a parent router forces a child router or a remote to join only this parent’s network. Setting this
parameter to 0xFF in a router or remote allows them to join with any parent. In a tree-routing system, the
InitialParentNwkID parameter also determines the hopping pattern for the parent and children of each
network. When a network ID equals or exceeds the number of unique hopping patterns, the hopping
pattern selection will “wrap around” to the network ID modulo of the number of hopping patterns. To
prevent interference between networks in a tree-routing system, networks with the same hopping pattern
must be physically separated by enough distance that they cannot receive transmissions from each other.
It is often convenient to set the InitialParentNwkID parameter value on remotes to 0xFF to allow them to
connect to any parent device. However, setting the InitialParentNwkID parameter value to 0xFF on a
system with a large number of routers can be problematical. This could result in very long routing paths,
slowing communications, and possibly causing reply delays to exceed the P2PReplyTimeout parameter
setting. For this reason, it is often best to design a tree-routing system using a large number of routers so
that each router has an explicit InitialParentNwkID.
SecurityKey - this sets the 128-bit AES encryption key to be used. To protect the key, this is a write-only
parameter for the user (always reads back as 0x2A). Refer to the Section 2.16 for further information.
SleepMode - this parameter enables sleep mode, which may be used in conjunction with the automatic
I/O reporting feature to wake up on specified triggers. Sleep mode is only available for remotes, and the
channel access mode for the network must be one of the CSMA modes.
