stac9708 ETC-unknow, stac9708 Datasheet - Page 27

• Manufacturer Part Number: stac9708
• Description: Multi-channel Ac97 Codec With Multi-codec Option
• Manufacturer: ETC-unknow

SigmaTel, Inc.
4.4.1 Reset Register (Index 00h)
Writing any value to this register performs a register reset, which causes all registers to revert to their
default values. Reading this register returns the ID code of the part.
4.4.2 Play Master Volume Registers (Index 02h, 38h, and 06h)
These registers manage the output signal volumes. Register 02h controls the stereo LINE_OUT master
volume (both right and left channels), register 04h controls the surround stereo DAC_OUT volume, and
register 06h controls the mono volume output. Each step corresponds to 1.5 dB. The MSB of the
register is the mute bit. When this bit is set to 1 the level for that channel is set at - dB. ML5
through ML0 is for left channel level, MR5 through MR0 is for the right channel and MM5 through
MM0 is for the mono out channel.
The default value is 8000h for registers 02h and 06h(8080h for register 38h), which corresponds to 0
dB attenuation with mute on.
4.4.3 PC Beep Register (Index 0Ah)
This register controls the level for the PC Beep input. Each step corresponds to approximately 3 dB of
attenuation. The MSB of the register is the mute bit.
channel is set at -
PC_BEEP through the STAC9708/11 mixer is to eliminate the requirement for an onboard speaker by
guaranteeing a connection to speakers connected via the output jack. In order for this to be viable the
PC_BEEP signal needs to reach the output jack at all times. NOTE: the PC_BEEP is recommended to
be routed to L & R Line outputs even when the STAC9708/11 is in a RESET state. This is so that
Power On Self Test (POST) codes can be heard by the user in case of a hardware problem with the PC.
For further PC_BEEP implementation details please refer to the AC'97 Technical FAQ sheet. The
default value can be 0000h or 8000h, which corresponds to 0 dB attenuation with mute off or on.
MUTE
0
0
1
dB. PC_BEEP supports motherboard implementations. The intention of routing
Mx5…Mx0
00 0000
01 1111
xx xxxx
Table 9. Play Master Volume Register
Preliminary
27
46.5 Attenuation
0dB Attenuation
FUNCTION
dB Attenuation
When this bit is set to 1 the level for that
RANGE
Req.
Req.
Req.
STAC9708/11
10/02/98