NAME
harmony —
CS4215/AD1849 audio
interface
SYNOPSIS
harmony* at gsc?
audio* at harmony?
DESCRIPTION
Theharmony 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
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.