FLY E185
Service Manual
CKT Confidential
Page 25 of 47
Block diagram of digital circuits of the audio front-end
To communicate with the external Bluetooth module, the master-mode PCM interface and
master-mode I2S/EIAJ interface are supported. The clock of PCM interface is 256 kHz while the
frame sync is 8 kHz. Both long sync and short sync interfaces are supported. The PCM
interface can transmit 16-bit stereo or 32-bit mono 8 kHz sampling rate voice signal. Note that the
serial data changes when the clock is rising and is latched when the clock is falling.
The audio front-end essentially consists of voice and audio data paths. All voice band data paths
comply with the GSM specification. Mono hands-free audio or external FM radio playback paths
are also provided. The audio stereo path facilitates CD-quality playback, external FM radio, and
voice playback through a headset. The APB register block is an APB peripheral that stores settings
form the MCU. The DSP audio port (DAP) block interfaces with the DSP for control and data
communications. The digital filter block performs filter operations for voice band and audio band
signal processing. The digital audio interface (DAI) block communications with the system
simulator for FTA or external Bluetooth modules.
To communicate with the external Bluetooth module, the master-mode PCM interface and
master-mode I2S/EIAJ interface are supported. The clock of PCM interface is 256 kHz while the
frame sync is 8 kHz. Both long sync and short sync interfaces are supported. The PCM interface
can transmit 16-bit stereo or 32-bit mono 8 kHz sampling rate voice signal.
