AK5371A Datasheet, PDF (29/32 Pages) Asahi Kasei Microsystems – 2ch A/D Converter with USB I/F

ASAHI KASEI
[AK5371A]
5.2 Endpoint Control Request
The AK5371A supports five sampling frequencies. The sampling rate is changed when “Set Endpoint
Control Request ” is issued. SET_CUR, GET_CUR of bRequest is only supported. GET_MIN, GET_
MAX, and GET_RES of bRequest are not supported.
5.2.1 Set Endpoint Control Request
Offset
0
1
2
Field
bmRequestType
bRequest
wValue
4
wIndex
6
wLength
Size Value
1 0x22
1 0x01
2 0x0100
2 0x0081
2 0x0003
Description
SET_CUR
Upper byte: SAMPLING_FREQ_CONTROL (0x01)
Lower byte : zero
Upper Byte : zero
Lower Byte : Endpoint Address (0x81)
The Length of Sampling Frequency Parameter
Block
The parameter block of mute control is the following.
Offset Field
Size Value
Description
0
iSampleFreq
3 0xYYYYYY The following five values are valid. Others are
invalid.
0x001F40 : 8kHz
0x002B11 : 11.025kHz
0x005622 : 22.05kHz
0x00AC44 : 44.1kHz(default)
0x00BB80 : 48kHz
If the iSampleFreq is different from the above values, the AK5371A forces sampling frequency to the
appropriate value.
5.2.2 Get Endpoint Control Request
Offset
0
1
2
Field
bmRequestType
bRequest
wValue
4
wIndex
6
wLength
Size Value
1 0xA2
1 0x81
2 0x0100
2 0x0081
2 0x0003
Description
GET_CUR
Upper byte: SAMPLING_FREQ_CONTROL (0x01)
Lower byte : zero
Upper Byte : zero
Lower Byte : Endpoint Address (0x81)
The Length of Sampling Frequency Parameter
Block
The parameter block of mute control is the following.
Offset Field
Size Value
Description
0
iSampleFreq
3 0xYYYYYY The following five values are valid.
invalid.
0x001F40 : 8kHz
0x002B11 : 11.025kHz
0x005622 : 22.05kHz
0x00AC44 : 44.1kHz
0x00BB80 : 48kHz
Others are
MS0546-E-00
MS0103-E-00
29
2007/02