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Modes of operation
9XTend-PKG-R RS-232/485 RF Modem User Guide
32
Note: When parameters are sent, they are two bytes long with the least significant byte sent first. Binary commands
that return one parameter byte must be written with two parameter bytes.
Commands can be queried for their current value by sending the command logically ORed (bit-wise) with the value
0x80 (hexadecimal) with CMD asserted. When the binary value is sent (with no parameters), the current value of the
command parameter is sent back through the DO pin.
Binary Command Write then Read
In this graph, a value was written to a register and then read out to verify it. While not in the middle of other received
data, note that the CTS signal outlines the data response out of the modem.
IMPORTANT: In order for the modem to recognize a binary command, the RT (GPI1 Configuration) parameter must be
set to one. If binary programming is not enabled (RT parameter value is not equal to ‘1’), the modem will not
recognize that the CMD pin is asserted and therefore will not recognize the data as binary commands.
For a binary programming example, see
on page 36 (DT command example returns two bytes).
Signal #4 is CMD
Signal #1 is the DI signal
Signal #2 is the DO signal from the
radio
Signal #3 is CTS