Audio Configuration - HP Compaq D315 Technical Reference Manual

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
PCI
Conf.
Addr. Register
00-01h Vender ID
02-03h Device ID
04-05h PCI Command
06-07h PCI Status
08h Revision ID
09h Class Code
0Ch Cache Line Size
0Dh Latency Timer
0Eh Header Type
0Fh BIST
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
Offset
Addr. / Register
00h Reset
02h Master Vol.
04h Reserved
06h Mono Mstr. Vol.
08h Reserved
0Ah PC Beep Vol.
0Ch Phone In Vol.
0Eh Mic Vol.
10h Line In Vol.
12h CD Vol.
5-30 Compaq D315 and hp d325 Personal Computers
Featuring the AMD Athlon XP Processor
Table 5-21.
AC'97 Audio Controller
PCI Configuration Registers (MCP Device 36Function 0)
Value on
Reset
10DEh
01B1h
0200h
00B0h
A1h
040100h
00h
00h
80h
00h
Table 5-22.
AC'97 Audio Codec Control Registers
Value
On Offset
Reset Addr. / Register
0100h 14h Video Vol.
8000h 16h Aux Vol.
-- 18h PCM Out Vol.
8000h 1Ah Record Sel.
-- 1Ch Record Gain
8000h 1Eh Reserved
8008h 20h Gen. Purpose
8008h 22h 3D Control
8808h 24h Reserved
8808h 26h Pwr Mgnt.
Second Edition – April 2003
PCI
Conf.
Addr. Register
10 – 13h Audio Base Addr.
14 – 17h Audio Bus Mstr. Addr.
18 – 1Bh Audio Mem. Base Addr.
34h Capabilities Pointer
3Ch Interrupt Line
3Dh Interrupt Pin
3Eh Minimum Grant
3Fh Maximum Latency
44h Power Management Config.
46h Power Mgmnt. Capabilities
Value
On Offset
Reset Addr. / Register
8808h 28h Ext. Audio ID.
8808h 2Ah Ext. Audio Ctrl/Sts
8808h 2Ch PCM DAC SRate
0000h 32h PCM ADC SRate
8000h 34h Reserved
-- 72h Reserved
0000h 74h Serial Config.
0000h 76h Misc. Control Bits
-- 7Ch Vender ID1
000xh 7Eh Vender ID2
Value
on
Reset
1d
1d
0s
44h
00h
01h
02h
05h
01h
FE02h
Value
On
Reset
0001h
0000h
BB80h
BB80h
--
--
7x0xh
0404h
4144h
5340h