Sequential shifter

Overview

A sequential shifter is a spring-returned lever with two momentary contacts: pushing the lever closes one contact and pulling it closes the other. Since the lever has no Parking/Reverse/Neutral/Drive gate, the device derives both gear shifts and mode changes from the same two contacts — a short actuation shifts a gear, and a long actuation changes the transmission mode. This is the same technique as in the Paddle as shifter configuration.

Prerequisites

  • The shifter's two contacts connected to two separate inputs of the device.
  • Contacts wired as digital inputs should switch the pin to signal ground. Contacts that provide a voltage signal instead should use analog switch inputs.

Input configuration

Each lever direction provides two functions:

  • Primary — short actuation — upshift/downshift command.
  • Secondary — long actuation — mode change trigger.

This is achieved by configuring two inputs on the same pin with different filtering parameters:

Parameter Primary input Secondary input
Enable filter On On
Delay 50 ms 500 ms
Hold 200 ms 200 ms

See Digital Input for a description of the filter parameters.

A short actuation fires only the primary input, while a long actuation first fires the primary input (after 50 ms) and then the secondary input (after 500 ms). A long actuation therefore always triggers both inputs — the mode table below is designed with this behaviour in mind. See Paddle as shifter for a detailed explanation of the timing.

The Delay of the secondary input can be adjusted to the driver's preference, but it should remain significantly longer than the Delay of the primary input, so an accidental tap of the lever cannot change modes. Please also make sure the mode-change safety conditions (safety map) are configured, so an unintended trigger cannot cause an unexpected mode change.

Inputs should be assigned as follows:

Function Input
Drive Lever pull secondary
Reverse Lever push secondary
Upshift Lever pull primary
Downshift Lever push primary

Mode configuration

The device uses a state-machine table that lets you define how the modes change on activation of each assigned input. Modes are represented by columns, each row represents an input trigger, and each cell holds the new mode that is engaged when that input triggers in that mode:

Input Reverse Parking Neutral Drive Manual Sport
Drive Neutral Drive Drive Drive Drive Drive
Reverse Reverse Neutral Reverse Neutral Neutral Neutral
Upshift Neutral Parking Neutral Drive Manual Sport
Downshift Reverse Parking Neutral Drive Manual Sport
Other Reverse Parking Neutral Drive Manual Sport

How it works

The logic is identical to the Paddle as shifter example — refer to that page for a step-by-step walkthrough of each transition. In short:

  • A single long pull of the lever engages Drive (from Reverse it first passes through Neutral, because the primary Upshift trigger fires before the secondary Drive trigger).
  • Switching from Drive to Reverse requires two long pushes: the first one switches Drive → Neutral, the second one Neutral → Reverse. This asymmetry is intentional — engaging Reverse should always require a deliberate, repeated action.
  • Short actuations shift gears and leave the mode unchanged (except in Reverse, where a short pull switches to Neutral).

The Manual and Sport columns are shown for completeness — with only the four lever triggers configured here they are never entered. If the shifter or the dashboard provides an additional button, it can be assigned as a dedicated trigger (for example Neutral, or a Drive/Manual toggle) to simplify the table and reach these modes.

Troubleshooting

  • Modes change on a short actuation: the secondary Delay is too short — increase it so only a deliberate long actuation triggers a mode change.
  • A long actuation does not change the mode: the lever is released before the secondary Delay elapses — reduce the Delay or hold the lever longer.
  • One actuation shifts twice: raise the Hold value on the primary input to reject contact bounce.

Remarks

This is an example configuration. It is intended to showcase how the device works and how to set up the mode transitions. If desired, this configuration can be extended or modified to fit more complex scenarios.