Audio Card Programming; Configuration; D.3.1 Configuration - Compaq Deskpro EP 6233 Technical Reference Manual

Appendix D Audio Card
D.3

AUDIO CARD PROGRAMMING

All programming aspects of the audio card relate directly to the programmability of the ES1868
controller, upon which the audio card is based. This section describes only the basic mapping of
the audio functions. For a detailed description of the ES1868s registers and capabilities refer to
the ES1868 AudioDrive Data Sheet, ESS Technology, Inc. document number SAM0011.
D.3.1

CONFIGURATION

The audio card is automatically configured as to base address, DMA, and interrupts following
installation and power up through an on-board EEPROM that provides Plug 'n Play support.
Software can identify the ES1868 controller by reading indexed address 2n5.40h successively,
which should yield the values 17h, 98h, followed by the base address of the ES1868.
The typical reset/power-up configuration for the audio card is as follows:
The audio card can be configured or either single DMA channel mode or dual DMA channel
mode. Single DMA channel mode means that capture and playback operations share the same
(playback) DMA channel and only one operation, capture or playback, is possible at a time. Dual
DMA channel operation allows simultaneous capture/playback (full duplex) operation to occur if
desired, but requires the use of two DMA channels. Typically, dual DMA operation would use
DMA channel 1 for capture (recording) and DMA channel 0, 1, or 3 for playback.
D-8 Compaq Personal Computers
Base Address:
Interrupt:
DMA Channel:
Power Management:
Original - February 1998
220h
IRQ5
1
Automatic