If you're new to the Xbox Adaptive Controller, have a look at these resources:
If you need to dive into deeper details, check out these Xbox Adaptive Controller Input Specifications. These are incredibly helpful in detailing the pinouts and voltages for all of the ports, particularly the analog ports for joystick control.
The XAC works just like a standard Xbox controller in terms of wireless connection with the Xbox, however it only sports a few of the typical buttons -- D-pad (6) , A button, B button, menu (3), Xbox button (1), menu button (3), and view button (2).
All of the missing inputs, along with the ones already physically present, can be controlled by external devices plugged into the 3.5mm jacks along the back of the XAC.
For example, you can see here that the Y, X, B, and A buttons are all represented as 3.5mm jacks, where you can plug in four larger buttons if needed.
Thanks to the Copilot Mode, you can use a standard Xbox controller in tandem with the XAC, so two users can work together as a single player, or one use can use both if that suits their needs.
Next, we'll look at the standards used with these jacks so you can interface your own digital buttons, switches, and analog devices with them.
Digital Input Standard
The 3.5mm inputs jacks on the XAC allow you to connect any type of switch that can open and close a circuit between the internal Ground and a 1.8V pin that is internally read on the device. These pins have internal-pull up resistors, so you can think of them just like you do any switch used in a microcontroller project.
These jacks are a standard stereo audio-type jack, and have Tip, Ring, Sleeve (TRS) connections. However, only Tip and Sleeve contacts are used.
So, in order to press a button on a digital input port, we simply need to ground the tip to the sleeve.
Represented another way, we can see that the Tip and Sleeve wires coming from a typical stereo cable can be shorted via a switch or button to create the connection that signal a button press.
Analog Input Standard
There are four jacks on the XAC that can accept variable resistance analog inputs, such as potentiometers -- X1, X2, LT, and RT. These map to the left thumb stick, right thumb stick, left trigger, and right trigger.
In order to read dual potentiometers and provide ground and reference voltages, these ports require the use of a four-pole TRRS plug. This is what is commonly found on mobile phone earbuds that include a microphone.
This is how the connections are used:
- Tip = wiper output from potentiometer 1 for X axis
- Ring 1 = wiper output from potentiometer 2 for Y axis
- Ring 2 = Ground
- Sleeve = 3.3V reference voltage
Here you can see two potentiometers from a typical analog joystick connected to the proper poles of the TRRS jack. Note, one potentiometer is inverted to provide the proper orientation of signal values as used on most joysticks. This isn't of too much concern however, as values can be remapped in software configuration on the game console.
Now that we understand how the inputs work, let's wire up some components!
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