HP D315 manual Audio Configuration, Audio Control, AC’97 Audio Codec Control Registers

Chapter 5 Input/Output Interfaces

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 AC’97 audio controller function of the MCP. Table 5-21 lists the key 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 (MCP Device 36Function 0)

PCI		Value on	PCI		Value
Conf.		Reset	Conf.		on
Addr.	Register		Addr.	Register	Reset
00-01h	Vender ID	10DEh	10 – 13h	Audio Base Addr.	1d
02-03h	Device ID	01B1h	14 – 17h	Audio Bus Mstr. Addr.	1d
04-05h	PCI Command	0200h	18 – 1Bh	Audio Mem. Base Addr.	0s
06-07h	PCI Status	00B0h	34h	Capabilities Pointer	44h
08h	Revision ID	A1h	3Ch	Interrupt Line	00h
09h	Class Code	040100h	3Dh	Interrupt Pin	01h
0Ch	Cache Line Size	00h	3Eh	Minimum Grant	02h
0Dh	Latency Timer	00h	3Fh	Maximum Latency	05h
0Eh	Header Type	80h	44h	Power Management Config.	01h
0Fh	BIST	00h	46h	Power Mgmnt. Capabilities	FE02h

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

		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	--	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	--	1Ch	Record Gain	8000h	34h	Reserved	--
0Ah	PC Beep Vol.	8000h	1Eh	Reserved	--	72h	Reserved	--
0Ch	Phone In Vol.	8008h	20h	Gen. Purpose	0000h	74h	Serial Config.	7x0xh
0Eh	Mic Vol.	8008h	22h	3D Control	0000h	76h	Misc. Control Bits	0404h
10h	Line In Vol.	8808h	24h	Reserved	--	7Ch	Vender ID1	4144h
12h	CD Vol.	8808h	26h	Pwr Mgnt.	000xh	7Eh	Vender ID2	5340h

5-30Compaq D315 and hp d325 Personal Computers Featuring the AMD Athlon XP Processor

Second Edition – April 2003