multiple hall sensors

With the interrupts, make sure you are correctly mapping your pins to the actual interrupt numbers

attachInterrupt(digitalPinToInterrupt(pin), ISR, mode);

so you code would look something like this:

attachInterrupt(fdriverHall1, isr1, RISING);
attachInterrupt(fdriverHall2, isr2, RISING);
attachInterrupt(fdriverHall3, isr3, RISING);
attachInterrupt(fdriverHall4, isr4, RISING);