CM108

Integration Dual DAC, Earphone Driver, ADC,

Microphone Booster, PLL, Regulator, and USB Transceiver

Date: Nov/01/2004

Version: 1.5

- 10 -

4. I²S INTERFACE

CM108 provide I

P

2

P

S interface for both playback and recording. External ADC, DAC, or DSP

can be added to provide additional function in the USB audio system. CM108 sends out the

master clock (fixed at x256), LRCK (fixed at x64), and data clock. Therefore external ADC,

DAC, or DSP should be set at slave mode for I

P

2

P

S interface. Left channel of I

P

2

P

S bus is used for

CM108 mono recording. Both I

P

2

P

S buses use 5V tolerant pad so they can be easily interfacing

with 5V or 3.3V devices. Playback data is simultaneously sent to both DAC and I

P

2

P

S bus.

Recording source (from ADC or from I

P

2

P

S bus) can be selected by ADSEL jumper pin.

LRCK

SCLK

MSB

-1

-2

+2

+1

LSB

MSB

-1

-2

+2

+1

LSB

SDATA

Left Channel

Right Channel