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WM_PRJ_Q2686_PTS_001-010
June 30, 2009
Q2686 Wireless CPU
®
3.21
Digital Audio Interface (PCM)
Digital audio interface (PCM) interface mode allows connectivity with audio
standard peripherals. It can be used, for example, to connect an external audio
codec.
The programmability of this mode allows to address a large range of audio
peripherals.
PCM features:
•
IOM-2 compatible device on physical level
•
Master mode only with 6 slots by frame, user only on slot 0
•
Bit rate single clock mode at 768kHz only
•
16 bits data word MSB first only
•
Linear Law only (no compression law)
•
Long Frame Synchronization only
•
Push-pull configuration on PCM-OUT and PCM-IN
The digital audio interface configuration cannot differ from that specified
above.
3.21.1
Description
The PCM interface consists of 4 wires:
•
PCM-SYNC (output): The frame synchronization signal delivers an 8 kHz
frequency pulse that synchronizes the frame data in and the frame data
out.
•
PCM-CLK (output): The frame bit clock signal controls data transfer with
the audio peripheral.
•
PCM-OUT (output): The frame “data out” relies on the selected
configuration mode.
•
PCM-IN (input): The frame “data in” relies on the selected configuration
mode.
