In this article We are going to make a review about the Arduino Pro Mini Board, in the end of this post, we will have all the necesary information to built the Arduino Pro Mini as we have from factory ...
The schematic does not drive a speaker directly from SP0256 pin 24. It uses a filter/coupling network followed by an amplifier: SP0256 DIGITAL OUT -> 33k series -> 0.022 uF shunt to GND -> 33k series ...