HARMONY(4) - Device Drivers Manual (hppa) #

HARMONY(4) - Device Drivers Manual (hppa)

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 #

ioctl(2), audio(4), gsc(4), intro(4), random(4)

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.

OpenBSD 7.5 - May 31, 2007