STAC9766 IDT [Integrated Device Technology], STAC9766 Datasheet - Page 38

• Manufacturer Part Number: STAC9766
• Manufacturer: IDT [Integrated Device Technology]

IDT™
TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING
STAC9766/9767
TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING
5.5.
AC-link Interoperability Requirements and Recommendations
5.5.1.
“Atomic slot” Treatment of Slot 1 Address and Slot 2 Data
Command or Status Address and Data cannot be split across multiple AC-link frames. The following
transactions require that valid Slot 1 Address and valid Slot 2 Data be treated as “atomic” (insepara-
ble) with Slot 0 Tag bits for Address and Data set accordingly (that is, both valid):
1. AC‘97 Digital Controller write commands to Primary CODECs
2. AC‘97 CODEC status responses
Whenever the AC‘97 Digital Controller addresses a Primary CODEC or an AC‘97 CODEC responds
to a read command, Slot 0 Tag bits should always be set to indicate actual Slot 1 and Slot 2 data
validity.
When the AC‘97 Digital Controller addresses a Secondary CODEC, the Slot 0 Tag bits for Address
and Data must be 0. A non-zero, 2-bit CODEC ID in the LSBs of Slot 0 indicates a valid Read or
Write Address in Slot 1, and the Slot 1 R/W bit indicates presence or absence of valid data in Slot 2.
AC‘97 Digital Controller
Primary Read Frame N,
SDATA_OUT
AC‘97 Digital Controller
Primary Write Frame N,
SDATA_OUT
AC‘97 CODEC Status
Frame N+1,
SDATA_IN
AC‘97 Digital Controller
Secondary Read Frame N,
SDATA_OUT
AC‘97 Digital Controller
Secondary Write Frame N,
SDATA_OUT
AC‘97 CODEC Status
Frame N+1,
SDATA_IN
Function
Function
Table 12. Secondary CODEC Addressing: Slot 0 tag bits
Table 11. Primary CODEC Addressing: Slot 0 Tag Bits
(Valid Frame)
Slot 0, bit 15
(Valid Frame)
Slot 0, bit 15
1
1
1
1
1
1
38
(Valid Slot 1 Address)
(Valid Slot 1 Address)
Slot 0, bit 14
Slot 0, bit 14
1
1
1
0
0
1
STAC9766/9767
(Valid Slot 2 Data)
(Valid Slot 2 Data)
Slot 0, bit 13
Slot 0, bit 13
0
1
1
0
0
1
Slot 0, Bits 1-0
(CODEC ID)
Slot 0, Bits 1-0
(CODEC ID)
01, 10, or 11
01, 10, or 11
PC AUDIO
00
00
00
V 7.4 12/06
00