XBUS
XBUS exposes the EuroRack Bus externally.
There is a switch to connect or disconnect the +12V/-12V rails, and another switch which connects or disconnects the +5V rail, CV and Gate signals.
If your bus doesn’t provide +5V, there is a jumper to simulate the +5V rail with a voltage divider, which should be fine for running a micocontroller-based module that doesn’t pull much current from the +5V bus line.
The three power rails are also protected by resettable fuses (polyfuses.) There are six fuses altogether, two for each rail—a primary, and an alternate fuse. If any fuse is blown, it should reset within 24 hours. Meanwhile, after you discover and fix the cause of the problem, you can use the jumpers on XBus to switch the rail(s) with the broken fuse(s) over to using an alternate “back-up fuse.”
There are patch points on the module to access the Bus CV and the Bus Gate signals. If these lines are not already being driven by your bus or by another module, you can use these patch points to drive CV and Gate lines on your existing bus.