alc658 Realtek Semiconductor Corporation, alc658 Datasheet - Page 14

• Manufacturer Part Number: alc658
• Description: Six-channel Ac?97 2.3 Audio Codec
• Manufacturer: Realtek Semiconductor Corporation

6.1.3.
Default: 0000H
This register controls the input volume for the PC beep signal. Each step in bits 4:1 corresponding to a 3dB increase/decrease
in volume. 16 levels of volume are available, from 0000 to 1111.
The purpose of this register is to allow the PC Beep signals to pass through the ALC658, eliminating the need for an external system
speaker/buzzer. The PC BEEP pin is directly routed (internally hardwired) to the Front-Out. If the PC speaker/buzzer is eliminated, it is
recommended to connect the external speakers at all times so the POST codes can be heard during reset.
6.1.4.
Default: 8008H
Register 0CH controls the telephone input volume for software modem applications. Because software modem applications
may not have a speaker, the CODEC can offer a speaker-out service. Each step in bits 4:0 corresponds to a 1.5dB
increase/decrease in volume, allowing 32 levels of volume, from 00000 to 11111.
Six-Channel AC’97 2.3 Audio Codec
For PB
For PV:
14:13
12:5
4:1
14:5
Bit
15
4:0
Bit
15
0
MX0A PC BEEP Volume
MX0C PHONE Volume
Type
R/W
R/W
R/W
Type
R/W
R/W
00h
0Fh
-
00h
08h
1Fh
Function
Mute Control 0: Normal
Reserved
Internal PCBEEP Frequency, F[7:0]
The internal PCBEEP frequency is the result of dividing the 48KHz clock by 4 times the number
specified in F[7:0].
The lowest tone is 48KHz/(255*4)=47Hz.
The highest tone is 48KHz/(1*4)=12KHz.
A value of 00h in F[7:0] disables internal PCBEEP generator and allows external PCBEEP input.
PC Beep Volume (PBV[3:0]) in 3 dB steps
Reserved
Function
Mute Control 0: Normal
Reserved
Phone Volume (PV[4:0]) in 1.5 dB steps
0 dB attenuation
45 dB attenuation
+12 dB Gain
0 dB attenuation
-34.5dB Gain
Table 8. MX0A PC BEEP Volume
Table 9. MX0C PHONE Volume
1: Mute (-∞ dB)
1: Mute (-∞ dB)
10
Datasheet
ALC658
Rev. 1.3