TIMTER™ Multi
-mode Dual
Telemetry Transmitter
100
Quasonix, Inc.
10 Appendix A
–
Preset Option
The preset feature operates similar to the stored presets in a car radio. The presence of this option is designated by
the characters “PS” and a number (2, 4, 8 or 16) appended to the standard model number. Transmitters with the
preset option operate as follows:
1.
The potential preset selection pins are pins 2, 6, 10, 11, 12 and 13 on the male MDM-15 connector, or pins
3, 7, 11, 12, 13 and 14 on the female MDM-15 connector. Of these pins, up to four may be used for presets
depending on the device options. To see which pins are used for presets and which bits they represent, use
the ZY command on the transmitter or refer to the documentation that came with your transmitter.
2.
Left floating, (the pins are pulled up to 3.3 VDC internally), a pin represents a “0”, grounded is a “1”.
3.
The 0000 state (all pins floating) provides normal operation.
4.
The (up to) 15 other states (one or more pins grounded) select one of the presets.
5.
Each preset stores a carrier frequency, modulation type, and various configuration values like randomizer,
data inversion, differential encoding, etc. These settings can be viewed with the LC (list configurations)
command from a terminal.
6.
The preset pins are read only at power up. Changing the preset pins after power-on has no effect.
7.
The presets are set (in your lab) from the 0000 state, using the "SV" command. Storing a preset is done by
configuring the device as you wish it to operate, then saving the setup to a particular preset. The save is
performed by typing the following command:
SV x [name]
where x is the preset number (1-15 depending on the options) and name is an optional setup name stored
with the setup. Alternatively, issue the “SV” command with a single
-
digit parameter (1 thru 15). So, “SV
5”, for example will store the current frequency and modulation setting in preset 5. “SV”, with no numeric
value after it, reports the state of all presets. The LC command displays names for all setups or, if a setup
number is entered, all the settings for that particular configuration.
8.
Electrical connection note: The preset pins are connected directly to the FPGA in the unit, so it is important
that the voltage on those pins never get outside the range of zero to 3.3 VDC. Voltages outside this range
can cause permanent damage. Also, the internal pull-up is through a 25k Ohm resistor inside the FPGA, so
it is important that the pins have a high impedance to ground (> 1 M Ohm) when the pins are floating. A
true switch closure is ideal, although a transistor switch can be used as long as its “Off” impedance is
sufficiently high.
