wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 17

• Manufacturer Part Number: wm9714l
• Description: Ac?97 Audio Codec
• Manufacturer: Wolfson Microelectronics plc

Pre-Production
DEVICE DESCRIPTION
INTRODUCTION
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The WM9714L is a largely pin compatible upgrade to WM9712, with a PCM voice codec added. This
codec is interfaced via a PCM type audio interface which makes use of GPIO pins for connection.
It is designed to meet the mixed-signal requirements of portable and wireless smartphone systems. It
includes audio recording and playback, battery monitoring, auxiliary ADC and GPIO functions, all
controlled through a single 5-wire AC-Link interface. Additionally, PCM voice codec functions are
supported through provision of an additional voice DAC and a PCM audio serial interface.
A PLL is included to allow unrelated reference clocks to be used for generation of the AC link system
clock. Typically 13MHz or 2.048MHz clock sources might be used as a reference.
SOFTWARE SUPPORT
The basic audio features of the WM9714L are software compatible with standard AC’97 device
drivers. However, to better support additional functions, Wolfson Microelectronics supplies custom
device drivers for selected CPUs and operating systems. Please contact your local Wolfson Sales
Office for more information.
AC’97 COMPATIBILITY
The WM9714L uses an AC’97 interface to communicate with a microprocessor or controller. The
audio and GPIO functions are largely compliant with AC’97 Revision 2.2. The following differences
from the AC’97 standard are noted:
Some other functions are additional to AC’97:
PCM CODEC
The PCM voice codec functions typically required by mobile telephony devices are provided by an
extra voice DAC on the WM9714L, which is interfaced via a standard PCM type data interface, which
is constructed through optional use of 4 of the GPIO pins on WM9714L. The audio output data from
one or both of the audio ADCs can also be output over this PCM interface, allowing a full voice codec
function to be implemented. This PCM interface supports sample rates from 8 to 48ks/s using the
standard AC’97 master clock.
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Pinout: The function of some pins has been changed to support device specific
features. The PHONE and PCBEEP pins have been moved to different locations
on the device package.
Package: The default package for the WM9714L is a 7×7mm leadless QFN
package.
Audio mixing: The WM9714L handles all the audio functions of a smartphone,
including audio playback, voice recording, phone calls, phone call recording, ring
tones, as well as simultaneous use of these features. The AC’97 mixer architecture
does not fully support this. The WM9714L therefore uses a modified AC’97 mixer
architecture with three separate mixers.
Tone Control, Bass Boost and 3D Enhancement: These functions are implemented
in the digital domain and therefore affect only signals being played through the
audio DACs, not all output signals as stipulated in AC’97.
On-chip BTL loudspeaker driver for mono or stereo speakers
On-chip BTL driver for ear speaker (phone receiver)
Auxiliary mono DAC for ring tones, system alerts etc.
Auxiliary ADC Inputs
2 Analogue Comparators for Battery Alarm
Programmable Filter Characteristics for Tone Control and 3D Enhancement
PCM interface to additional Voice DAC and existing audio ADCs
PLL to create AC’97 system clock from unrelated reference clock input
PP, Rev 3.2, October 2008
WM9714L
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