Wiring a hall effect sensor to a VR input

[ssmith]

This is in reference to rusEFI Huge but I bet it applies to more boards.

I have a lot of hall effect (or 12v driven signals) that I want to connect as inputs, more than exist on rusEFI Huge. Studying the circuit diagram (and just thinking about it) it seems that it should be possible to connect driven 12V signals to a VR input.

1. Connect VR- to, say, 5V or 8V.
2. Connect VR+ to driven signal, possibly with a pullup resistor if the sensor doesn't have one.

It sounds like the MAX99* VR circuits might have a slight delay in one direction but on a hall effect sensor I imagine the transition is pretty fast.

Seems simple enough, would that work? If so, can you update the documentation? Not sure where it best belongs, but there's:
https://github.com/rusefi/rusefi/wiki/Trigger-Configuration-Guide
https://github.com/rusefi/rusefi/wiki/FAQ-Basic-Wiring-and-Connections
I think these are the same but the formatting is different:
https://wiki.rusefi.com/Trigger-Configuration-Guide/
https://wiki.rusefi.com/FAQ-Basic-Wiring-and-Connections/

BTW would it make sense to include a default bias on all the V- line of 2.5V, kinda like the Huge board has a default bias of around 12V on VR+ on VR1 input (page 2 of https://raw.githubusercontent.com/rusefi/rusefi_documentation/master/Hardware/Hellen/alphax_8ch-c-schematic.pdf)
Or am I not reading that correctly? Or is it left floating to allow the ECU to be used as a piggyback on another system?

[AndreyB]

https://github.com/andreika-git/hellen-one/issues/285 and https://github.com/andreika-git/hellen-one/issues/124 could be relevant