Arduino Pro Mini 3V3 Voltage pins

Hello guys!

Why do I have around 2V on pin 9 when I call digitalWrite() or analogWrite(254), when pinMode(9, OUTPUT);
Shouldn’t be 3V3?

My Arduino Pro Mini 3V3 is connected through FTDI on mini USB.

Thank’s.

Only Pin 9?

Is there anything else connected to the pin?

What is your 3V3 (or VCC) pin measuring?

There is 3.2V on VCC. I have connected one piezzospeaker on pin 9 and one BMP085 pressure sensor on vcc and A4, A5. Once the usb is connected shouldn't be 3.3V on all pins?

Thank you.

Once the usb is connected shouldn't be 3.3V on all pins?

Not if you are using the 3.3V version of the Mini Pro...

Which,

There is 3.2V on VCC

Implies you are using the 3.3V version.

The Pins will not be any higher than VCC.

I want to use the maximum voltage on pin 9(3.3V) so a high volume level will be on piezzospeaker, but there is something like 2V on the pin. Shouldn't be 3.3V?

Is it 2V with or without the speaker connected?

I connect the speaker and I play a continuous tone, for ex. 1500Hz with digitalwrite HIGH, and I Have 2v. I want to have a biger volume.

connect the speaker and I play a continuous tone, for ex. 1500Hz with digitalwrite HIGH

That statement contradicts itself. If you digitalWrite(9, HIGH) then there will be NO frequency on pin 9. If there is no frequency, then where does the tone come from?

When a frequency is present, that means the signal is turning ON and OFF. The duty cycle of that waveform will determine what DC voltage is present.

If there is PWM going out of the pin, and you are using a DMM to measure the voltage then I,m not surprised its only reading 2v as the meter will average the voltage measured. If you use a scope to look at the output then you'll probably find it is indeed at 3v3. Texy