STAC9750 Datasheet, PDF (27/73 Pages) Integrated Device Technology – VALUE-LINE TWO-CHANNEL AC’97 CODECS

STAC9750/9751
VALUE-LINE TWO-CHANNEL AC’97 CODECS
PC AUDIO
Audio input frame slot 1’s stream echoes the control register index, for historical reference, for the
data to be returned in slot 2. (Assuming that slots 1 and 2 had been tagged “valid” by STAC9750/
9751 during slot 0.)
Bit
19
18:12
11:2
1:0
Table 13. Status Address Port Bit Assignments
Description
Reserved
Control Register Index
Slot Request
Reserved
Comments
Stuffed with 0
Echo of register index for which data is being returned
see sections below
Stuffed with 0
The first bit (MSB) generated by STAC9750/9751 is always stuffed with a 0. The following 7 bit posi-
tions communicate the associated control register address, and the trailing 12 bit positions are
stuffed with 0 by the STAC9750/9751.
5.1.2.2. Slot 2: Status Data Port
The status data port delivers 16-bit control register read data.
Table 14. Status Data Port Bit Assignments
Bit
Description
19:4
Control Register Read Data
3:0
Reserved
Comments
Stuffed with 0 if tagged “invalid”
Stuffed with 0
If Slot 2 is tagged “invalid” by STAC9750/9751, then the entire slot will be stuffed with 0's.
5.1.2.3. Slot 3: PCM Record Left Channel
Audio input frame slot 3 is the left channel output of STAC9750/9751 input MUX, post-ADC.
STAC9750/9751 ADCs are implemented to support 18-bit resolution.
STAC9750/9751 outputs its ADC data (MSB first), and stuffs any trailing non-valid bit positions with 0
to fill out its 20-bit time slot.
5.1.2.4. Slot 4: PCM Record Right Channel
Audio input frame slot 4 is the right channel output of STAC9750/9751 input MUX, post-ADC.
STAC9750/9751 outputs its ADC data (MSB first), and stuffs any trailing non-valid bit positions with 0
to fill out its 20-bit time slot.
5.1.2.5. Slot 5: Reserved
Audio input frame slot 5 is Reserved for modem operation and is not used by the STAC9750/9751.
This slot is always stuffed with 0.
IDT™
VALUE-LINE TWO-CHANNEL AC’97 CODECS
27
STAC9750/9751
V 5.8 103106