NAME
harmony —
CS4215/AD1849 audio
interface
SYNOPSIS
harmony* at gsc?
audio* at harmony?
DESCRIPTION
The
harmony device uses the Crystal Semiconductor CS4215
16-Bit Multimedia Audio Codec or Analog Devices AD1849 SoundPort(R) Stereo
Codec chip to implement the audio device interface described in
audio(4). This device is found
on most HP PA-RISC workstations. The
harmony has a maximum
precision of 16 bits and has a stereo input and stereo output.
On HP 9000/712 models
harmony also provides two additional
channels for an add-on card with two fax/voice modems.
One of the hardware registers reflects the state of the CHI bus that is used to
communicate with the codec and thus being sampled at a low accuracy secondary
frequency (such as
timeout(9)) produces poor
quality random bit stream that is fed into the entropy pool of
rnd(4).
MACHINES
An incomplete list of machines that feature
harmony audio:
- 712/*
- 715/*
- 725/*
- 735/*
- 755/*
- B132L[+], B160L, B180L+
- C100, C110, C132L, C160[L],
C180, C200, C240, C360
- J200, J210[XC], J280, J282,
J2240
SEE ALSO
hppa/ioctl(2),
audio(4),
hppa/gsc(4),
hppa/intro(4),
rnd(4)
HISTORY
Support for
harmony first appeared in
OpenBSD
3.3. It was ported to
NetBSD 1.6 by Chuck
Silvers.
CAVEATS
To trigger entropy collection CHI bus has to be programmed into the data mode
that happens once a single buffer of data has been played or recorded.