Skip to content

Commit

Permalink
firmware: platform: Remove avoid_pwm_pll and make it enabled by defau…
Browse files Browse the repository at this point in the history
…lt. PWM audio will always resample
  • Loading branch information
popcornmix committed Oct 11, 2015
1 parent d56bf18 commit ba7a8fb
Show file tree
Hide file tree
Showing 8 changed files with 0 additions and 0 deletions.
Binary file modified boot/fixup.dat
Binary file not shown.
Binary file modified boot/fixup_cd.dat
Binary file not shown.
Binary file modified boot/fixup_db.dat
Binary file not shown.
Binary file modified boot/fixup_x.dat
Binary file not shown.
Binary file modified boot/start.elf
Binary file not shown.
Binary file modified boot/start_cd.elf
Binary file not shown.
Binary file modified boot/start_db.elf
Binary file not shown.
Binary file modified boot/start_x.elf
Binary file not shown.

2 comments on commit ba7a8fb

@imzyxwvu
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Would this change make the sound quality worse?

@popcornmix
Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

No. The quality of the resampling is very much higher than the analogue audio quality.

Note: avoid_pwm_pll did used to harm quality by using a fractional clock. This commit does things a but differently.

When the de-popping was added a couple of years back we started resampling all analogue audio to 48KHz anyway. But 48KHz needs a dedicated PLL (or suffers from a fractional divide). This change makes the default output frequency 48.828125KHz which we can get from an existing PLL without a fractional divisor.

Feel free to test, but the resampling won't be audible.

Please sign in to comment.