Is any way to use analog pins of arduino PRO MINI to read dc fan RPM ... becouse i've no free PWM Digital pins (.
Analog pins A0 to A5 can be used in exactly the same way as digital pins. A6 and A7 can be used as analog read pins only. PWM is not relevant for reading.
What sensor do you intend to use to measure the RPM of the fan ?
In this case you have nothing to do with pwm. You can use a hall effect sensor with a magnet and measure RPM with pin change interrupt. It doesn't matter if you use digital or analog pins.
al exmples with reading dc fan speed as i see done at Digital pins .... so i have ask ... so at my senario there is no difference between D pins and A pins ... Am I right ?
Analogue pins can be used for digital signals.
A0-A5 are basically digital pins that also have analog reading ability.
A6 and A7 are analog in only (so probably not useful for your application).