82801BA Datasheet, PDF (205/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Functional Description
Table 5-88. Featured Supported by ICH2 (Continued)
Feature
PCI Modem
function
AC-link
Multiple Codec
Description
• Read/write access to modem codec registers 3Ch-58h and vendor registers 5Ah–7Eh
• 16-bit mono modem line1 output and input, up to 48 kHz (slot 5)
• Low latency GPIO[13:11,8:6,4:3,1:0] (GPIO[13:11,8:7,4:3,1:0] for the ICH2-M) via
hardwired update between slot 12 and PCI IO register
• Programmable PCI interrupt on modem GPIO input changes via slot 12 GPIO_INT
• SCI event generation on primary or secondary SDIN wake-up signal
• AC’97 2.1 compliant AC-link interface
• Variable sample rate output support via AC’97 SLOTREQ protocol
(slots 3,4,5,6,7,8,9)
• Variable sample rate input support via monitoring of slot valid tag bits (slots 3,4,5,6)
• 3.3 V digital operation meets AC’97 2.1 DC switching levels
• AC-Link IO driver capability meets AC‘97 2.1 dual codec specifications
• Codec register status reads must be returned with data in the next AC-link frame, per
AC’97 2.1 specification.
• Dual codec addressing: All AC’97 codec register accesses are addressable to codec
ID 00 (primary) or codec ID 01 (secondary)
• Dual codec receive capability via primary and secondary SDIN pins
(primary, secondary SDIN frames are internally validated, synchronized, and OR’d)
Note: Throughout this document, references to D31:F5 indicate that the audio function exists in PCI
Device 31, Function 5. References to D31:F6 indicate that the modem function exists in PCI
Device 31, Function 6.
Figure 5-20. ICH2 Based AC’97 2.1
Audio In (Record)
PC
Audio Out (Playback)
Modem
Mic.
5.18.1 AC-link Overview
The ICH2 is an AC’97 2.1 compliant controller that communicates with companion codecs via a
digital serial link called the AC-link. All digital audio/modem streams and command/status
information is communicated over the AC-link.
The AC-link is a bi-directional, serial PCM digital stream. It handles multiple input and output data
streams, as well as control register accesses, employing a time division multiplexed (TDM)
scheme. The AC-link architecture provides for data transfer through individual frames transmitted
in a serial fashion. Each frame is divided into 12 outgoing and 12 incoming data streams, or slots.
The architecture of the ICH2 AC-link allows a maximum of two codecs to be connected.
Figure 5-21 shows a two codec topology of the AC-link for the ICH2.
82801BA ICH2 and 82801BAM ICH2-M Datasheet
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