so, the full story. I have another topic here on how to detect a square wave signal +12v/-12v. That topic is solved, I received a lot of great suggestions.
However, The full story is that once I detect that the 12v/-12v 1Khz square wave signal a car ECU generates stopped, I want another device (arduino) to take over the ask from the ECU and to generate similar +12v/-12v signal - at 1Khz, duty cycle is 50%.
As I know, it is not possible to generate negative voltage with arduino - is there anyone who knows how to make such a signal?