STAC9704 datasheet(27/49 Pages) HYNIX

27 / 49 page

SigmaTel, Inc.

STAC9704/7

10/02/98

Table 11: PC_BEEP Register

MUTE

PV3…PV0

FUNCTION

0000

0 dB Attenuation

1111

45 dB Attenuation

xxxx

∞ dB Attenuation

4.4.4 Analog Mixer Input Gain Registers (Index 0Ch - 18h)

These registers control the gain/attenuation for each of the analog inputs. Each step corresponds to

approximately 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. Register 0Eh (Mic Volume Register) has an extra bit that is for a 20dB

boost. When bit 6 is set to 1, the 20 dB boost is on. The default value is 8008, which corresponds to 0

dB gain with mute on. The default value for the mono registers is 8008h, which corresponds to 0dB

gain with mute on. The default value for stereo registers is 8808h, which corresponds to 0 dB gain with

mute on.

Table 12: Analog Mixer Input Gain Register

MUTE

Gx4…Gx0

FUNCTION

00000

+12 dB gain

01000

0 dB gain

11111

-34.5 dB gain

xxxxx

∞ dB gain

4.4.5 Record Select Control Register (Index 1Ah)

Used to select the record source independently for right and left. The default value is 0000h, which

corresponds to Mic in.

STAC9704 Datasheet(PDF) 27 Page - Hynix Semiconductor