hall sensor using pin change intrerrupt

Hi! I work on my personal project for an electric gate. I have two motors with Hall sensors. Also i have an receiver witch use external pin intrerrupt (pin2). My board is an arduino pro mini (Atmega 328@16Mhz) Now, what i do and where is the problem. 1. tested Hall sensor using external pin intrerrupt (pin 3) and work as expected. I see about 600 changes per second 2. because i have only two external interrupt pins and one is occupied by RF receiver i like to use Hall sensor on another digital pin configured for pin change intrerrupt. Following some guidance find on internet i make an setup for pin A0. Tested with one wire connected/disconnected from ground and worked. So, from software perspective everything is ok. But when i try to use Hall sensor with this pin (A0 in my case) not work as expected. It's like pin is keep on HIGH.

So, what i can do next? 1. using analogRead to see how voltage is changing and use that, but analogRead is slow and need to use it twice for each motor. Anyway, i will test this later. 2. is there another RF library that don't require external interrupt. Now i'm using RCSwitch witch work nice but need to use pin 2 or 3. 3. any solution to use Hall sensor from motor on ordinary digital pin?

Thanks for reply!

Fixed (code implementation)! Because interrupt occur very frequently, command like Serial.print don't feet wheel when is used inside ISR function, because require much time. So i keep only minimal code in ISR and move Serial.println in loop routine. Now i can see how counter is incremented and everything work as expected. In conclusion, pin change interrupts can be used with Hall sensor from motors if don't have disposable an external interrupt. In my case a see about 600 changes/per second when using external intrerupt (so 300 rising or falling interrupts) and when i use pin change interrupts i got same value, so at this speed work very well.