wts701 Winbond Electronics Corp America, wts701 Datasheet - Page 17

• Manufacturer Part Number: wts701
• Description: Winbond Single-chip Text-to-speech Processor
• Manufacturer: Winbond Electronics Corp America

WTS701
VFS (CODEC Synchronization Line)
The CODEC synchronization line supplies a frame synchronization signal to the internal CODEC. This
is a digital input. After receipt of a synchronization pulse, the CODEC will output data on the VDX line.
The VFS line expects an 8kHz sample rate and supports both short frame and long frame
synchronization signal.
VDX (CODEC Data Transmit Line)
The CODEC data transmit line is a digital output that places digital audio data onto the CODEC bus.
The line is in a tri-state condition until the device is due to transmit data. The data output from the VDX
line is selected by the SCOD Command. When WTS701 places data on the VDX line, it is required
that the VFS line should be in tri-state condition when another device is connected to the CODEC as
well.
7.2.7 The Analog Interface
The WTS701 provides an on-chip analog interface for audio output via an 8
speaker driver or an
:
output buffer capable of driving a 5k
load. Additionally, an analog input (AUXIN) allows an audio
:
signal to be fed through the WTS701 chip to either output device. The command SAUD configures the
analog path. A digitally controlled attenuator provides volume control via the SVOL command.
The following is a description of the analog pins:
AUXIN (Analog Input)
The AUXIN is an additional audio input to the WTS701. This input has a nominal 694 mV p-p level at
its minimum gain setting (0 dB) (See
Table
2). Additional gain is available in 3 dB steps (controlled by
the SAUD Command) up to 9 dB. The use and equivalent circuit of the input amplifier is shown in
Figure 7.
(Must be AC coupled)
Internal to the device
Rb
C
= 0.1 µF
Ra
COUP
1
f
NOTE:
=
CUTOFF
2SR
C
a
COUP
Figure 7. AUXIN Input Amplifier.
Publication Release Date: May 2003
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Revision 3.09