Set this option for ports that control noise-making devices, such as solenoids and motors.
Each port marked with this flag will be deactivated when Night Mode is engaged. These ports will operate only when Night Mode isn't in use.
If you're using the Night mode feature, you should first go through your devices and figure out the port you're going to connect each device to. Then, set the "Noisy" flag for each noise-making device. When you turn on Night Mode, these devices will be disabled, allowing you to play more quietly.
If you're not using the Night Mode feature, you can ignore this option.
If this option is set, the controller applies "gamma correction" to the port. This adjusts the intensity level of the port on a curved scale so that it better matches the way the human eye perceives brightness.
Gamma correction is best for ports connected to lighting devices like lamps and LEDs. When used with lights, gamma correction makes "fading" effects look more linear to the eye, and improves RGB color mixing accuracy. You generally shouldn't use gamma correction with other device types, such as solenoids and motors.
The gamma correction option is only available for ports with PWM capability, because it only affects intermediate intensity levels between fully off and fully on. The ends of the curve - 0% and 100% brightness - are the same with or without gamma correction. This means that you can't gamma-correct digital-only ports, such as Digital GPIO ports, 74HC595 outputs, and chime board outputs.
To keep things simple, the controller uses a fixed gamma of 2.8. Even though the ideal gamma does vary a little from one device to the next, and can even be affected by other variables (e.g., ambient lighting), the fixed 2.8 gamma should work well enough for most lighting devices, and should at least be an improvement over purely linear brightness.
This option reverses the voltage levels for ON and OFF for a GPIO output port.
By default, ports are "active high", meaning that the output controller sets the port's GPIO pin to "high" (3.3V) when the software port is ON, and sets it to "low" (0V) when the software port is OFF.
Setting this option reverses those voltages. An "active low" port's GPIO pin is "low" (0V) when the software port is ON, and "high" (3.3V) when the software port is OFF.
Don't use this option with the MOSFET "booster circuit" described in the Build Guide. That circuit is designed for the default Active High triggering.
Do use this option if you're using some other type of booster circuit that requires active-low triggering. This is fairly common among third-party "relay boards" designed for Arduino projects, for example. If you have a relay board that instructs you to connect the control input to "Ground" or "GND" or 0V to trigger it, it's an active-low design and you should select this option.
Note that this option only works with GPIO ports. The Expansion Board ports and the external output chips (TLC5940 and 74HC595) have different designs that can't use this feature. In the case of the expansion boards, it's moot anyway because those boards have their own booster circuits built in.