MSP430FR6989: Water Meter Reference Design for three LC Sensors, Using Extended Scan Interface (ESI)

hello ,

I will implement the LC sensing meter soon .

So far i am studying on the Water Meter Reference Design for three LC Sensors, Using Extended Scan Interface (ESI).

I want to ask some question:

1) why there exist both 2 and 3 LC sensing application note?

for 2LC sensing , it mentioned that 2 sensor need to place 90 degree so that they are out of phase, i guess it may relate to later the 4 state diagram of 00,01,10,11, right?

and so why up to three lc sensor and how the placement of three lc sensor? and if so do the state up to 8(000,001,.....,111), now?

2)for page 6 of the application notes "Water Meter Reference Design for three LC Sensors, Using Extended Scan Interface (ESI)"

do the PSM and the TSM are both part inside the ESI ? so the main cpu running is only when the Q6 flag have interrupt?

thanks

Jeff