Guru
Joined: 05/03/2018
Location: NetherlandsPosts: 5849
| Posted: 02:16pm 30 Nov 2022 |
@cosmic frog, @mixtel90,
Can you please check if PAM8403 works ?
The PAM8403 changes a (small) analog signal into PWM (class D) and feeds it to the speaker.
In picomite case there is no analog signal, there is a PWM signal (44kHz). If I feed that unfiltered to a PAM8403 you PWM modulate a PWM signal.
That may very well not work at all.
If you need to convert the picomite PWM signal to analog (the filter with inductor, or the 1 transistor active filter), then attenuate it, then feed it to the PAM8403, you might as well connect the loudspeaker directly to the filter/buffer.
Maybe Phill's solution is the best and simplest. Use the PWM at GP0/GP1 and use it to drive the speaker directly (via a 100uF capacitor), and it is tested !!!
Regards,
Volhout
Edited 2022-12-01 00:22 by Volhout