
CVSD CODEC Evaluation Kit
7
EV6090 Evaluation Kit
2001 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. # 20480218.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
All trademarks and service marks are held by their respective companies.
3.3.3
S1 and S2 Switch Settings
Circuit Condition When Switch
Is:
Switch
Name
Description
ON
OFF
S1-C1
CLKMODE1
Used in conjunction with
CLKMODE2 to set
sampling rate and source
(internal or external).
See table on EV6090 for switch
combinations.
S1-C2
CLKMODE2
Used in conjunction with
CLKMODE1 to set
sampling rate and source
(internal or external).
See table on EV6090 for switch
combinations.
S1-C3
ALGORITHM
Determines whether 3-bit
or 4-bit companding
algorithm will be used. In
general, 3-bit companding
yields better results at
rates of 32kbps and
below, while 4-bit
companding should be
used at 48kbps and
above.
4-bit algorithm
3-bit algorithm
S1-C4
DATAEN
This switch is used in
combination with the
/POWERSAVE switch to
determine the state of the
CMX639 encoder output.
Encoder
output is at
high
impedance
regardless of
state of
/POWERSAVE
switch.
Encoder output is
enabled if
/POWERSAVE
switch is OFF,
and is set to VSS if
it is ON.
S2-C1
/ENCODERFORCEIDLE
This switch causes a
“perfect idle” pattern of
0101… to be present at
encoder output.
Encoder
produces idle
pattern at
output.
Encoder operates
normally.
S2-C2
DECIN
This switch selects the
source of the decoder
input signal.
Decoder input
taken from
PCMCIA
interface.
Decoder input
taken from either
DECIN screw
terminal or
encoder output.
S2-C3
/DECODERFORCEIDLE
This switch causes a
0101… pattern to be
internally applied to the
CMX639 decoder,
resulting in the decoder
output pin going to VDD/2.
Decoder
output is
VDD/2.
Decoder operates
normally.