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> Can pics be used to generate audible tones?

Yes. The simplest way would be to toggle an output pin with a timer

For example, to make a 1kHz tone with 50% duty cycle, you need
the timer set to rollover/interrupt every 0.5ms, as 1kHz = 1ms period,
and for half the period the pin = 0, half the period the pin = 1

A project of mine that's sidelined is to send the PIC a serial stream
containing note pitch and duration to be a simple programmable short
tune player (beeps/sequences for buttons, menus etc) . Uses two
timers, one for pitch. one for duration. Data would be held in permanent
memory for playback retrieval

The PIC hasn't enough drive for a speaker and would need at least
a basic current amplifier such as transistor, with the speaker as the
load. A piezo disc can be driven either between two PIC pins or
between PIC pin and 0V. The sound would be similar in quality and
volume to what you get from a birthday or Christmas card. The sound
can be softened with an RC filter, which will somewhat round the
corners of the square wave and make the sound less harsh. Be aware
that piezos can act as voltage generators and an external tap for
instance could blow the PIC pin(s)

More volume can got by boosting the voltage applied across the
piezo and using a buffer transistor. See the two example methods in
the gifs attached. A piezo is a capacitive component and voltage is
LC boosted by the small inductor in parallel. A resistor in parallel
acts as a load for the transistor, as the piezo will charge quickly with
one cycle but not discharge for the next

wbr

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