One of the world’s top three mobile phone manufacturers has chosen austriamicrosystems’ AS3521 mobile entertainment IC as the basis for the audio section of a new cell phone model with sophisticated music and audio features
The AS3521 is a totally self-contained digital audio system-on-a-chip, fitting easily into the baseband architecture of different GSM/EDGE and CDMA chipsets. By using a serial communication interface the phone’s baseband processor issues commands to the mobile music chip, where all digital and analog music processing is handled locally. Thus the baseband processor is free to execute the communication software stack and the user interface, while the AS3521 plays MP3 and AAC-encoded songs out of the mobile phone’s music memory.
“Both of the color displays of the clamshell-style phone can be used to navigate the playlist, control music playback and establish the user’s preferred sound settings,” said Alexander Harrer, senior vice president of austriamicrosystems’ communications business. “The music player can be operated even with the phone closed, because the AS3521 supports buttons on the outer shell of the phone, duplicating the music-related keys of the inner keypad.”
When the cell phone is connected to a PC via its USB 2.0 full-speed interface, the phone identifies itself as an external storage device in true plug-and-play fashion.
No dedicated drivers or cumbersome installation procedures on the PC are required. The AS3521 controls the phone’s USB link and the music Flash memory. It can handle fast music downloads as well as uploads of recorded voice notes, radio programs or photographs.
austriamicrosystems’ mobile entertainment chip drives a stereo headset as well as stereo speakers in the phone. It increases the user’s listening pleasure by providing 3D enhanced stereo sound. A freely configurable equaliser allows the user to adjust the music to his or her personal taste. MIDI ringtones from a polyphonic source, as well as stereo FM radio programs, can be merged into the audio stream. The AS3521 controls the FM radio via a dedicated serial interface.
austriamicrosystems’ mobile music chip has its own internal programmable power management unit making it independent of the phone’s main PMU. It also supplies regulated battery power to the FM module.
The AS3521’s clean subsystem concept together with a powerful firmware library and software design tool suite enabled the developers to get the entertainment phone to the market within just a few months.