Emu68PWM 4.6

Short:        AHI driver: Pi 3/4 audio jack, PiStorm
Author:       hakke@gmx.de (Andreas Winkler)
Uploader:     hakke gmx de (Andreas Winkler)
Type:         driver/audio
Version:      4.6
Requires:     PiStorm with Raspberry Pi 4/CM4 or 3, Emu68 1.1+, AHI 6
Architecture: m68k-amigaos >= 3.1
Distribution: Aminet
Kurz:         AHI-Treiber für die Klinkenbuchse des Pi 3/4 am PiStorm

Emu68 PWM is an AHI driver that plays through the 3.5mm audio jack of
the Raspberry Pi 4 or Pi 3 in a PiStorm (a PiStorm32-lite, or a classic
PiStorm in an A500) running Emu68: a further stereo output next to Paula
and next to the HDMI output of emu68hdmi.audio. Ideal as the headphone
(cue) output of a DJ program such as StormDJ, or as a second output for
a second program.

This is a beta version, tested on a Pi 4 in a PiStorm32-lite and on a
Pi 3 in a classic PiStorm, mostly with StormDJ. Please report problems
to hakke@gmx.de, with your Pi model, your Emu68 version and the output
of PWMDiag.

Features
--------
- Two AHI modes, 16-bit stereo 48 kHz: normal (12 x 16 ms buffer) and
  low latency (3 x 16 ms), for Units 0-3 and the music unit.
- About 11 bits of resolution: fine for headphones and monitoring.
- Soft start and stop: no thump from the jack.
- AHI's output volume (Prefs/AHI "Output volume"), with a smooth ramp,
  from -60 dB up to a +12 dB boost for headphones.
- Optional dither for quiet passages, chosen as the unit's Output in
  Prefs/AHI.
- DMA paced by the PWM hardware, completion by interrupt: about 62
  wake-ups a second, no polling.
- AHI's CPU overload protection, as in paula.audio.
- Installs next to emu68hdmi.audio: different mode IDs (001f0020,
  001f0021), different hardware, both can be in Prefs/AHI.
- PWMTest: a test tone through the jack without AHI, for troubleshooting.
- PWMDiag: what the driver did, for problem reports.
- An AmigaGuide manual.

Requirements
------------
- A PiStorm with a Raspberry Pi 4 or CM4, or a Raspberry Pi 3 B, B+
  or A+ (not a Pi Zero 2 W: it has no jack).
- Emu68 1.1 or newer with its embedded ROM (devicetree.resource,
  mailbox.resource; on the Pi 4 gic400.library 1.3+).
- AHI 6.x.

Installation
------------
From the archive:

  Copy Emu68PWM/Devs/AHI/emu68pwm.audio DEVS:AHI/
  Copy Emu68PWM/Devs/AudioModes/Emu68PWM DEVS:AudioModes/

Reboot and pick an Emu68 PWM mode in Prefs/AHI. See Emu68PWM.guide.

Credits
-------
Built on emu68hdmi.audio 4.17 (arczi84, flype44; GPL-3.0-or-later).
PWM sound set-up after Circle by R. Stange (GPL-3.0-or-later).
Emu68 and its resources by Michal Schulz, AHI by Martin Blom.

Author: Andreas Winkler - www.taiwanrider.com
(HAKKE Online Shop, Amiga and synthesizer related hardware and software).

License
-------
GNU General Public License, version 3 or later: see COPYING. The complete
source code is in the Source drawer of this archive; please pass the
archive on complete, with it.

Disclaimer
----------
Emu68 PWM is provided "as is", without warranty of any kind. You use it
at your own risk: the author takes no responsibility for any loss of
data or for any damage to software or hardware, whatever the cause.

History
-------
4.6     First public release.