XStream™
OEM
RF
Module
–
Product
Manual
v5.x00
[2006.02.24]
Binary Commands
Sending and receiving parameter values using binary commands is the fastest way to change
operating parameters of the module. Binary commands are used most often to sample signal
strength (RS parameter) and/or error counts; or to change module addresses and channels for
polling systems when a quick response is necessary. Since the sending and receiving of
parameter values takes place through the same serial data path as 'live' data (received RF
payload), interference between the two types of data can be a concern.
Common questions about using binary commands:
What are the implications of asserting CMD while live data is being sent or received?
After sending serial data, is there a minimum time delay before CMD can be asserted?
Is a time delay required after CMD is de-asserted before payload data can be sent?
How does one discern between live data and data received in response to a command?
The CMD pin [pin 5] must be asserted in order to send binary commands to the module. The
CMD pin can be asserted to recognize binary commands anytime during the transmission or
reception of data. The status of the CMD signal is only checked at the end of the stop bit as the
byte is shifted into the serial port. The application does not allow control over when data is
received, except by waiting for dead time between bursts of communication.
CMD (pin 5) must be asserted in order to send binary commands to an XStream Module. CMD
can be asserted to recognize commands anytime during transmission or reception of data. A
minimum time delay of 100 µs (after the stop bit of the command byte has been sent) must be
observed before pin 5 can be de-asserted. The command executes after all parameters
associated with the command have been sent. If all parameters are not received within 0.5
seconds, the module aborts the command and returns to Idle Mode. Note: When parameters are
sent, they are always two bytes long with the least significant byte sent first.
Commands can be queried for their current value by sending the command logically ORed 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.
Figure
2
‐
11.
Binary
Command
Write
then
Read
Signal
#4
is
CMD
(pin
5)
Signal
#1
is
the
DIN
(pin
4)
signal
to
the
radio
Signal
#2
is
the
DOUT
(pin
3)
signal
from
the
radio
Signal
#3
is
(pin
1)
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
signal
outlines
the
data
response
out
of
the
module.
IMPORTANT: For the XStream Module to recognize a binary command, RT (DI2 Configuration)
Command must be issued. If binary programming is not enabled (RT
≠
1), the
module will not recognize that the CMD pin (Pin 5) is asserted and therefore will not
recognize the data as binary commands.
©
2006
MaxStream,
Inc.
Confidential
and
Proprietary
17
electronic components distributor
