alc885-gr Realtek Semiconductor Corporation, alc885-gr Datasheet - Page 96

• Manufacturer Part Number: alc885-gr
• Description: 7.1+2 Channel High-performance Hda Codec With Content Protection
• Manufacturer: Realtek Semiconductor Corporation

11.3. Digital Microphone Implementation
This section describes the ALC885 digital microphone implementation. There is one Clock output pin
and 1 Data input pin in the ALC885. The ALC885 provides the clock signal to the digital microphone.
When the digital microphone receives the external sound input, it converts the analog signals to digital in
a 1-bit format. The 1-bit data is delivered to the codec though the data input pin. The Digital Filter in the
audio codec converts the 1-bit data stream into Pulse Code Modulation (PCM) data. The PCM data is sent
to the HDA controller through the HDA link.
The ALC885 supports a two-wire interface for the digital microphone and operates in single channel
(mono type) or stereo channels (stereo mode) of digital microphones. One pin is clock output to the
digital microphone, and the other is a serial pin. The default clock output is 2.048MHz.
In Type 1 (Figure 25), the ALC885 uses one data pin to support mono input from digital microphones
with LMV1024 (L), SPD0205ND (L), or AKU2000 (L).
In Type 2 (Figure 25), the ALC885 uses one data pin to support stereo inputs from digital microphones
with LMV1024/1026 (L/R), SPD0205ND (L & R), or AKU2000 (L & R).
7.1+2 Channel High-Performance HDA Codec
With Content Protection
Figure 24. Digital Microphone Implementation-1
Figure 25. Digital Microphone Implementation-2
88
ALC885 Series
Datasheet
Rev. 1.1