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
ioctl(2),
audio(4),
gsc(4),
intro(4),
rnd(4)
HISTORY
Support for
harmony
first appeared in
OpenBSD3.3.
It was ported to
NetBSD1.6
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.