D. led feedback, Section 3.d – Pololu TReX User Manual
Page 9
Warning:
The Vcc column is tied to the output of a linear voltage regulator, so its current output is
limited by thermal dissipation. The regulator will only be able to safely supply a maximum of 100 mA
when VIN is 16 V (it has a 1-W power dissipation rating). This is typically sufficient for powering an
analog joystick or RC receiver, but it is insufficient for powering servos. If you want to connect servos
to some of your RC receiver channels, you must power your RC receiver separately and disconnect
the BEC jumper. Attempting to use the TReX’s regulated Vcc line to power servos can permanently
damage the TReX.
• Mode-Select Jumper: This jumper specifies the interface that is in control of the TReX. When it shorts
the left two pins (as shown in the jumper image above), the TReX is in RC mode, which means the TReX is
expecting RC pulse inputs on its five input channels and that these RC signals will determine the motor outputs.
When the jumper shorts the right two mode pins, the TReX is in analog mode; the TReX measures the analog
voltages on the five input channels and sets the motor outputs accordingly. When there is no jumper on the
three mode pins, the TReX is in serial mode and the serial interface controls the motors. The control interface is
determined by the location of the mode jumper when the TReX is first powered up. Changing the location of the
mode jumper while the TReX is running will have no effect.
• Learning-Mode/Firmware-Upgrade Jumper: The TReX can automatically calibrate itself for your RC or
analog controller by learning the neutral and extreme values for each channel you use. It also has the ability to
upgrade its firmware. When placed across the SO and G pins, this jumper puts the TReX into learning/firmware-
upgrade mode via the “secret handshake” (see
). The TReX ships with this jumper in place since we
recommend your first step be to calibrate for your controller. This jumper should be removed before you begin
normal operation.
Warning:
You should never add this jumper while the board is powered! Disconnect power from the
board, add this jumper, and then reconnect power.
3.d. LED Feedback
This section explains the meanings of the various illumination patterns of the TReX’s LEDs. The TReX has eight
colored LEDs as shown below:
Pololu TReX User's Guide
© 2001–2013 Pololu Corporation
3. Getting Started
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