Protocol-formatted messages are discussed in detail in Section 7. Briefly, protocol-formatted messages include a start-of-
messages character, message length and message type information, the destination MAC address for the message, and
the message payload.
Transparent data is routed using the transparent mode destination address held in the
RmtTransDestAddr
parameter. The
default value for this parameter is the broadcast MAC address, 0xFFFFFF. The
TransPtToPtMode
parameter is enabled
by default, which causes a radio to unicast a packet to the peer from which it most recently received a message. These
two parameter defaults make a network consisting of two DNT90M radios “plug-and-play”, as they automatically select
each other’s MAC addresses for transmitting transparent data back and forth efficiently.
3.0 DNT90M Application Interfaces
A DNT90M module provides a variety of application interfaces including two serial ports, an SPI port, six digital I/O ports
(logic state), three 12-bit ADC input ports, and two 12-bit DAC output ports. Each of these interfaces is discussed below.
3.1
Serial Ports
The DNT90M includes two serial ports, one for communication and an optional one for diagnostics. The communication
port is a full-duplex UART interface with hardware flow control on two of the digital I/O pins an optional feature. One digital
I/O pin can also be configured as an RS485 enable function. The
serial communication port can be configured with baud rates from 1.2 to 250 kbps, with 9.6 kbps the
default baud rate. The DNT90M communication port transmits/receives 8-bit data with a choice of even, odd or no parity
and 1 or 2 stop bits. The default configuration is no parity and one stop bit. See Section 5.1 for recommendations on con-
figuring the communication port, and Section 7.4.4 for detailed information on configuration parameters. The diagnostic
port is enabled as an alternate function of the LINK and ACTIVITY pins, and can be configured with baud rates from 1.2 to
250 kbps, with 9.6 kbps the default baud rate. The diagnostic port transmits/receives 8-bit data with no parity and 1 stop
bit. See Section 7.4.8 for diagnostic port configuration details.
3.2
SPI Port
The DNT90M serial peripheral interface (SPI) port can operate either as a master or a slave. The port
includes the four standard SPI connections - MISO, MOSI, SCLK and /SS, plus three signals used to support SPI slave
mode operation - /HOST_RTS, /HOST_CTS and DAV. The serial port and SPI master mode can run simultaneously. Se-
rial port operation is disabled when the SPI port is configured for slave mode. Note that all SPI slave mode messages
must be protocol formatted.
©2012 by Murata Electronics N.A., Inc.
DNT90M Integration Guide (2012/09/17)
Page 11 of 74
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