SN74HC1G86

Yes, that's a real part number. SN74HC1G86 is a single 2-input exclusive-OR (XOR) logic chip from the 7400 series, and mirabarukaso named a ComfyUI node after it because the node behaves like one. It's a bit of a joke and a bit of a genuine design philosophy - the pack has a whole "74 family" of nodes modeled on logic ICs. Under the naming, this one does something useful: it passes through exactly one of two inputs, and blocks the output when both or neither are present.

It's a Logic/74 node in ComfyUI_Mira, the author's utility pack. If you've ever wanted "give me A, or B, but not both, and nothing if I've got both" as a single node, this is it. The trick that makes it interesting in ComfyUI is that its inputs and output are wildcard-typed, so it isn't limited to booleans - it can route any wire.

How it works

XOR means exclusive-or: true when the inputs differ, false when they match. This node applies that to routing. Per the pack's own truth table: if both A and B are active (True), the output Y is None; if both are inactive (False), Y is None; if only A is present, Y passes A; if only B is present, Y passes B. So it forwards the single "odd one out" and emits nothing when the two agree.

That None output is deliberate and is the key to how these nodes chain. Mira's logic nodes lean on None as a signal - other nodes in the pack (like Function Select Auto, or None To Zero) react to whether an input is None - so an XOR that produces None on a tie slots into a larger conditional graph where downstream nodes pick up whichever branch actually carried a value.

Inputs and outputs that matter

• A / B - the two inputs, both optional and wildcard-typed (*), so they accept any wire, not just booleans.
• Y - the output. Carries whichever single input was the exclusive one, or None when both or neither apply.

Because everything is wildcard-typed, think of it less as "boolean math" and more as "select exactly one of two, or pass nothing."

Installing it

ComfyUI Manager: search ComfyUI_Mira in the Custom Nodes Manager, Install, restart. Manual: cd ComfyUI/custom_nodes && git clone https://github.com/mirabarukaso/ComfyUI_Mira.git, then restart ComfyUI. If it errors on load, run pip install -r requirements.txt in the pack folder and restart. No models.

Common issues

The output being None is the thing to internalize, not a bug. If you plug Y into a node that can't handle a None input, a tie (both or neither active) will hand it nothing and you'll get an error there - which is why these 74-family nodes are meant to feed other Mira logic nodes that expect and interpret None, rather than being dropped mid-pipeline into a node that demands a concrete value. The README even jokes about the extra logic overhead: "it's Python, so who cares?" - the honesty is that this is a niche, hobbyist-flavored corner of the pack.

If you just want plain XOR on two booleans and nothing fancy, this does that too; read the truth table above and remember that "both true" gives None, not True. It's a genuinely different behavior from a boolean AND/OR, and that's the whole point of picking the XOR chip.