Support » Pololu TReX Jr User’s Guide » 4. RC/Analog in Detail »
4.a. Channel Functions
The five input channels along the left side of the TReX Jr accept either radio-controlled (RC) servo pulses or analog voltages, depending on the position of the mode-selection jumper (or on the value of the “channel input source” parameter if the TReX Jr is in serial mode). When not in serial mode, the TReX Jr acts on the five channels as follows:
- Channel 1: If mix jumper is in place, turn left/right at the specified speed; if mix jumper is off, set motor 1 direction and speed.
- Channel 2: If mix jumper is in place, go forward/reverse at the specified speed; if mix jumper is off, set motor 2 direction and speed.
- Channel 3: Set auxiliary motor speed (aux. motor is unidirectional).
- Channel 4: Enable/disable flipped mode. Flipped mode causes the TReX Jr to treat motor 1 as motor 2 (and vice versa), and to swap its notions of forward and reverse for each motor. The result is that a differential-drive robot will behave as normal when inverted if flipped mode is enabled. This channel acts like a switch that gets flipped when the channel value falls below a certain threshold. If your controller is not calibrated, this channel may not function as intended.
- Channel 5: Enable/disable serial override. Serial override gives serial control of the motors for as long as channel 5 enables it. When serial override is first enabled, each motor is set based on its most recently received motor command, even if that command occurred while serial override was disabled. Channels 1, 2, and 3 will not affect the motors while serial override is active (unless your serial control source is reading the values of those channels and issuing its commands based in part on them). This channel acts like a switch that gets flipped when the channel value falls below a certain threshold. If your controller is not calibrated, this channel may not function as intended.