Compaq 850 manual Audio Programming, Audio Configuration, Audio Control

Technical Reference Guide

5.8.5 AUDIO PROGRAMMING

Audio subsystem programming consists configuration, typically accomplished during POST, and control, which occurs during runtime.

5.8.5.1 Audio Configuration

The audio subsystem is configured according to PCI protocol through the ES1373 audio controller. Table 5-21 lists the PCI configuration registers of the audio subsystem.

Table 5–21. AC’97 Audio Controller PCI Configuration Registers

Table 5-21.

AC’97 Audio Controller

PCI Configuration Registers

PCI		Value	PCI		Value
Conf.		on	Conf.		on
Addr.	Register	Reset	Addr.	Register	Reset
00-01h	Vender ID	1274h	14-17h	Native Audio Bus Mstr. Addr.	0’s
02-03h	Device ID	1373h	18-1Bh	Reserved	0’s
04-05h	PCI Command	0000h	1C-2Bh	Reserved	0’s
06-07h	PCI Status	X610h	2C-2Dh	Subsystem Vender ID	1274h
08h	Revision ID	00h	2E-2Fh	Subsystem ID	1373h
09h	Programming	00h	30h	Exp. ROM Addr.	0’s
0Ah	Sub-Class	01h	34h	Capabilities Pointer	DCh
0Bh	Base Class Code	04h	3Ch	Interrupt Line	xxh
0Eh	Header Type	00h	3Dh	Interrupt Pin	01h
10-13h	Native Audio Mixer Base Addr.	1	3E, 3Fh	Min. GNT/Min, LAT	800Ch

5.8.5.2 Audio Control

The audio subsystem is controlled through a set of indexed registers that physically reside in the audio codec . The register addresses are decoded by the audio controller and forwarded to the audio codec over the AC97 Link Bus previously described. The audio codec’s control registers (Table 5-22) are mapped into 64 kilobytes of variable I/O space.

Table 5–22. AC’97 Audio Codec Control Registers

Table 5-22.

AC’97 Audio Codec Control Registers

		Value			Value			Value
Offset		On	Offset		On	Offset		On
Addr. / Register		Reset	Addr. / Register		Reset	Addr. / Register		Reset
00h	Reset	0100h	14h	Video Vol.	8808h	28h	Ext. Audio ID.	0001h
02h	Master Vol.	8000h	16h	Aux Vol.	8808h	2Ah	Ext. Audio Ctrl/Sts	0000h
04h	Reserved	X	18h	PCM Out Vol.	8808h	2Ch	PCM DAC SRate	BB80h
06h	Mono Mstr. Vol.	8000h	1Ah	Record Sel.	0000h	32h	PCM ADC SRate	BB80h
08h	Reserved	X	1Ch	Record Gain	8000h	5Eh	AC Mode Control	0080h
0Ah	PC Beep Vol.	8000h	1Eh	Reserved	X	60h	Misc. Cystal Cntrl.	0023h
0Ch	Phone In Vol.	8008h	20h	Gen. Purpose	0000h	68h	S/PDIF Cntrl.	0000h
0Eh	Mic Vol.	8008h	22h	3D Control	0000h	--		--
10h	Line In Vol.	8808h	24h	Reserved	X	7Ch	Vender ID1	4352h
12h	CD Vol.	8808h	26h	Pwr Mgnt.	000xh	7Eh	Vender ID2	5931h

Compaq Deskpro EXS and Workstation 300 Personal Computers 5-31

Featuring the Intel Pentium 4 Processor

First Edition - December 2000