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DNT24 Integration Guide - 10/19/11
send messages to their parent during a hop. As discussed above, the hop duration must be increased as
the number of slots are increased to achieve a specific RSS. The default
NumSlots
parameter value of
three is suitable for many applications.
De facto
TDMA operation (guaranteed bandwidth) can be implemented for up to 8 remotes by setting the
SlotLease
parameter to a value greater than any gaps in data being sent to a remote by its local host.
This will insure that the base keeps each remote’s slot reserved for it even when there is a gap in the data.
The
MsgsPerHop
parameter is configurable
for each
DNT24 in a system. This parameter is usually set to
a high value in the base and the routers, allowing traffic between a parent and multiple children on each
hop. The
MsgsPerHop
parameter has little effect in remotes except when a remote needs to send multi-
ple peer-to-peer messages during a hop. To support sending multiple messages on each hop, the BSS
and RSS must be sized accordingly, requiring a longer hop duration. Note that the messages must be
protocol messages and all messages to be sent on a single hop must be in the module before the module
begins to transmit.
5.0 DNT24 Application Interface Configuration
DNT24 modules include a comprehensive set of application interfaces and related options that support a
wide range of applications including wireless RS232/485 cable replacements, wireless sensor networks,
wireless alarm systems and industrial remote control applications. Recommended configuration steps for
each application interface are discussed in Sections 5.1 through 5.7 below.
5.1 Configuring the Serial Port
The default serial port configuration is 9.6 kbps, 8-bit data, no parity and 1 stop bit.
1. Configure the serial data rate as required from 1.2 to 250.0 kbps by setting the
SerialRate
parameter in Bank 3.
2. Configure the parity and number of stop bits by setting the
SerialParams
parameter in Bank 3.
3. Enable/disable serial port hardware flow control as required by setting the
GpioAlt
parameter in
Bank 6. Hardware flow control is disabled by default, but is recommended when operating at
higher baud rates and/or sending large blocks of data.
5.2 Configuring the SPI Port
1. Enable either SPI
master mode
or SPI
slave mode
by setting the
SpiMode
parameter in Bank 3.
The serial port remains operational in SPI master mode but is disabled in SPI slave mode.
2. If using SPI master mode:
a. Select the SPI clock rate by setting the
SpiRateSel
parameter in Bank 3 (default
is 125 kbps)
b. Set the SPI master command string and string length by setting the
SpiMasterCmdStr
and
SpiMasterCmdLen
parameters respectively in Bank 3.
3. Configure the edge trigger direction, bit-sampling edge and bit-order options by setting the
SpiOptions
parameter in Bank 3.
