IEI Integration ICE-DB-9S - Manual (Page 78)

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ICE Module
4.7 Audio Codec Interface(AC’97/HDA)
All COM Express module types support Audio Codec '97 (AC'97) and/or High
Definition Audio (HDA) Digital Interface (AC-link) specifically designed for
implementing audio and modem I/O functionality. The corresponding signals can be
found on the COM Express module connector rows A and B.
4.7.1 Signal Description
Table 4-17 shows COM Express audio bus signal, including pin number, signals, I/0,
power plane, terminal resistors, damping resistors and descriptions.
Table 4-17: Audio Signals Description
Pin Signal I/O Description
A30 AC_RST# O 3.3VSB CMOS CODEC Reset.
A29 AC_SYNC O 3.3V CMOS 48kHz fixed-rate, sample-synchronization signal to
the CODEC(s).
A32 AC_BITCLK O 3.3V CMOS 12.228 MHz Serial Bit Clock for CODEC.
A33 AC_SDOUT O 3.3V CMOS Serial TDM data output to the CODEC.
B30
B29
B28 AC_SDIN0
AC_SDIN1
AC_SDIN2 I 3.3VSB CMOS Serial TDM data inputs from up to 3 CODECs
4.8 Reference Circuit
Please refer to the schematic diagram of the baseboard. IEI baseboard is embedded
with the Realtek ALC888 audio controller. For the detailed specifications of the
Realtek ALC888, please go to http://www.realtek.com/ .
4.8.1 Audio Routing Guideline
4.8.1.1 Analog Power Delivery
Clean analog power delivery to the audio codec and other audio components utilizing
the 5-V analog supply is critical. Excessive system noise on this supply will degrade
the entire audio sub-system. Except the GND signal, users can use independent LDO
to generate clean audio analog power.