AK5374 Datasheet, PDF (43/51 Pages) Asahi Kasei Microsystems – 24-bit Stereo ADC with USB Interface

■ Audio Control Requests
[AK5374]
1. Set Feature Unit Control Request
1-1. Mute Control
Offset
0
1
2
4
Field
bmRequestType
bRequest
wValue
wIndex
6 wLength
Size Value
1 0x21
1 0x01
2 0x0100
2 0x0300
2 0x0001
Description
SET_CUR
MUTE_CONTROL | CHANNEL_0
Upper byte: bUnitID field in Feature Unit Control Descriptor
(0x03)
Lower byte: Audio Control Interface (0x00)
Length of parameter block
The parameter block of mute control is the following.
Offset
Field
Size Value
0 bMute
1 0x01
0x00
Mute
Not mute
Description
1-2. Volume Control
Offset
0
1
2
Field
bmRequestType
bRequest
wValue
4 wIndex
6 wLength
Size Value
1 0x21
1 0x01
2 0x0200
0x0201
0x0202
2 0x0300
2 0x0002
Description
SET_CUR
VOLUME_CONTROL | CHANNEL_0 (Master)
VOLUME_CONTROL | CHANNEL_1
VOLUME_CONTROL | CHANNEL_2
Upper byte: bUnit ID field in Feature Unit Control Descriptor
(0x03)
Lower byte: Audio Control Interface (0x00)
Length of Parameter Block
The parameter block of volume control is the following.
Offset
Field
Size Value
Description
0 wVolume
2 0xZZZZ The value is mapped to the volume register value. (Table 8)
(ZZZZ is assigned by Host.)
If the wVolume exceeds the range, the AK5374 adjusts the value into the range.
MS1197-E-00
- 43 -
2010/05