It is pretty cool indeed, however keep in mind that's just standard component in circuits to turn signals on and off. It is just a PNP or NPN transistor. Everyone makes use of it.
To be clear too, I'm just speculating about that part. The only thing this document says is that "This disconnect is implemented in hardware alone, and therefore prevents any software, even with root or kernel privileges in macOS, and even the software on the T2 chip, from engaging the microphone when the lid is closed." That implies to me that they are using some form of physical interlock (probably a magnet and Hall-effect sensor), and that they use this to completely disable the microphone. The most obvious way to me to do that in this case would be to cut the power with a transistor, but in principle there are a number of other ways it could be achieved.
Comments
That's pretty cool.
It is pretty cool indeed, however keep in mind that's just standard component in circuits to turn signals on and off. It is just a PNP or NPN transistor. Everyone makes use of it.
To be clear too, I'm just speculating about that part. The only thing this document says is that "This disconnect is implemented in hardware alone, and therefore prevents any software, even with root or kernel privileges in macOS, and even the software on the T2 chip, from engaging the microphone when the lid is closed." That implies to me that they are using some form of physical interlock (probably a magnet and Hall-effect sensor), and that they use this to completely disable the microphone. The most obvious way to me to do that in this case would be to cut the power with a transistor, but in principle there are a number of other ways it could be achieved.
I think it makes sense to assume they have a hall-effect sensor and a MOSFET but of course maybe they combined both in a single package.
Thinking how a hall-effect sensor works, perhaps it would be possible to embed it in a wafer with some gates and you're done.