NAME
harmony —
CS4215/AD1849 audio device
SYNOPSIS
harmony* at gsc? irq 13
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 random(4).
SEE ALSO
HISTORY
OpenBSD support for
harmony first appeared in OpenBSD
3.3.
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.