Pololu TReX - Manual (Page 10)

TReX LEDs
• Power LED (1): The blue power LED is located on the top board. When it is brightly illuminated, the TReX
is receiving power and is running. Note that the power LED can occasionally glow dimly when the TReX is
unpowered if it is connected serially to a powered device.
• Motor LEDs (5): Motors 1 and 2 each have two indicator LEDs—one red, one green—tied directly to the
motor outputs. These LEDs are located on the bottom (motor-driver) board and can be viewed through holes
in the top board. For a given motor, the color of the illuminated LED indicates its direction and the intensity
indicates its speed. Our convention is to consider the direction indicated by the green LED “forward” and the
direction indicated by the red LED “reverse”. The auxiliary motor output is directly tied to the yellow LED on
the lower edge of the top (control) board near the auxiliary motor port; the intensity of this LED indicates the
auxiliary motor speed.
• Status LEDs (2): The TReX has two status LEDs—one red and one green—located on the left side of the top
board. These LEDs are used to communicate a great deal of information to the user. The illumination patterns
mean different things depending on the TReX’s state.
◦ On TReX Startup:
▪ Status LEDs flash rapidly five times: When the TReX starts up, it signals which channels it has
learned by flashing its status LEDs five times. A green flash indicates the corresponding channel has
been learned; a red flash indicates the corresponding channel has not been learned. For example, a
flash sequence of “red, red, green, red, green” means only channels 3 and 5 have been learned. If the
TReX is in analog mode, it signals which analog channels have been learned; if it is in RC mode, it
signals which RC channels have been learned; if it is in serial mode, the learned-channel signals are
for the mode selected by the “channel input source” parameter (this parameter’s default value is RC
mode).
▪ Red and green LEDs blink in unison around once per second: The TReX is waiting to see if it
should enter learning mode. This happens when the TReX is in RC or analog mode, the mix jumper is
in place, and the serial out (SO) pin is grounded. This last condition can arise if the TReX is connected
Pololu TReX User's Guide © 2001–2013 Pololu Corporation
3. Getting Started Page 10 of 24