Picking an input
The Rolling Anti-Lag Switch setting assigns which ECU input reads your arming switch. Either an SPI (synchronized pulsed input) or an AVI (analog voltage input) will work. Which one you choose changes the settings you need to fill in.
Using an SPI
An SPI treats the switch as a digital signal, so you tell it which transition means "on."
| Setting | What it does | Our advice |
|---|---|---|
| Edge Select | Falling means the switch grounds the input when on. Rising means the switch feeds voltage to the input when on | Most dash switches ground the input, so Falling is the common choice |
| Sensor Type | How the input interprets the signal | Hall Effect for any switch input |
| Pullup | Holds the input at a voltage while the switch is open | Enable it for a ground-switching switch, otherwise the input floats when off |
Using an AVI
An AVI reads a voltage, so you set two thresholds: a Switch On Voltage and a Switch Off Voltage. Crossing the On value arms the function, and the voltage has to come back past the Off value before it disarms. Leaving a healthy gap between the two gives you tolerance for voltage wobble and electrical noise, so the function doesn't flicker on and off.
Two ways a switch commonly behaves, and how we'd set it:
| Switch behavior | Switch On Voltage | Switch Off Voltage | Result |
|---|---|---|---|
| Sits at 5V when off, pulled to 0V when on | 0.5V | 4.5V | Armed once it drops below 0.5V, disarmed once it climbs above 4.5V |
| Sits at 2.5V when off, goes to 12V when on | 4.5V | 3.0V | Armed once it rises above 4.5V, disarmed once it falls back below 3.0V |
With a 5V-to-ground switch, settings of 1.0V on and 4.0V off would also work. They just leave more room at each end. The idea is the same either way: put each threshold clearly inside the voltage the switch actually reaches, not right on the edge of it.
Flip the switch with the ECU connected and watch the input's live voltage or state in NSP. Confirm it changes cleanly both ways. It's the fastest way to catch a wrong edge, a missing pull up or thresholds that sit too close to the real voltage.
Next steps
Once the switch reads correctly, move on to the rolling anti-lag setup itself, then the ignition override and fuel correction tables. Rolling anti-lag is hard on turbos and exhaust parts, so build up gradually and watch your logs. A dual switch panel kit is a tidy way to add the arming switch.
