AVPro
5002C
Dual SCART A/V Switch
October 2000
DESCRIPTION
The AVPro
5002C device is an audio/video
switching IC that supports an input/output port, an
input only port, and an output only port. The device
includes multiplexers that allow the inputs to be
routed to the outputs in various configurations.
Additional outputs are provided to drive an external
RF modulator. The video outputs of the multiplexers
are buffered to drive 137-ohm loads. The audio
outputs are buffered to provide 2 Vrms output into
600 ohms. The 5002C has features optimized for
Canal+ satellite receiver applications, but it can also
be used in other applications that require control of
multiple audio and video sources.
FEATURES
Two SCART connections (Auxiliary, TV)
Video section
- Integrated output drivers
- RGB, SVHS, composite outputs
- Programmable RGB gain
Audio section
- Dual mode volume control
0 or 6 dB gains, plus 0 to -31 dB attenuations
- Programmable gain on DAC input channels
- Ground based outputs (no AC coupling caps)
Serial port control of switching I
2
C bus
64-lead LQFP package
BLOCK DIAGRAM
Aux_Lin
Rin
Lin
Aux_Rin
Aux_Rout
Aux_Lout
SCLK
SDATA
Enc_B
Enc_G
Enc_R
Aux_YCout
Aux_B
Aux_G
Aux_YC
TV_B
TV_G
TV_R
TV_YCout
EBLANK
ABLANK
BLANK
GN
D
Enc_YC
DO_1
DO_0
Aux_Cout
Mod_mono
Aux_R
Mod_YC
+5
V
D
C
Rbias
Vref
Support
Circuits
Tgen
-5
V
D
C
Enc_C
Enc_Y
TV_Fnc
-5
V
D
C
+
12VDC
Rout
Lout
TV_Rout
TV_Lout
Aux_Mono
+5
V
D
C
+5
V
D
C
+5
V
D
C
-5
V
D
C
-5
V
D
C
Mux
Mux
Serial
Port
GN
D
GN
D
GN
D
Volume
Control
Other I/O
Aux_Cin
Aux_Fnc
TV_Rin
TV_Lin
TV_YCin
Enc2_C
Enc2_Y
TDK SEMICONDUCTOR CORP.
AVPro
5002C
Dual SCART A/V Switch
2
FUNCTIONAL DESCRIPTION
The 5002C is an audio/video switching device. The
device integrates both audio and video drivers so
that it can directly drive the SCART interface. The
use of a -5 volt supply eliminates the need for AC
coupling capacitors on the audio outputs and the
SCART audio inputs. All programmable functions of
the device are controlled through a standard I
2
C
serial interface and a set of internal registers.
The device will interface to an external video
encoder that provides six video outputs. In addition,
the 5002C includes two programmable digital
outputs and provides inputs for the TV SCART
audio/video.
SCART VIDEO SWITCHING
The device is designed to accept video signals from
an auxiliary SCART connector, TV SCART
connector, and an external video encoder/DAC
device. The devices include a set of analog
multiplexers that receive video signals from these
sources and allow routing of the signals to the
various video outputs. The video output drivers have
a nominal gain of 2.0 V/V to allow for a series
resistance of 62 ohms prior to the 75 ohm
termination. A block diagram of the video switching
function is provided in Figure 1. Details of the
register settings are provided in the section titled
"Serial Port Register Tables".
Figure 1: 5002C Video switching block diagram
Enc_B
Enc_G
Enc_R
Aux_YCout
Aux_B
Aux_G
Aux_YC
TV_B
TV_G
TV_R
TV_YCout
EBLANK
ABLANK
BLANK
Enc_YC
Aux_Cout
Aux_R
Mod_YC
Enc_C
Enc_Y
TV_Fnc
Mux
VGen
Aux_Fnc
Comparator
0V
2V
Mux
Mux
Mux
Mux
Mux
Mux
Mux
Aux_Cin
TV_YCin
Gain
Mux
Enc2_Y
Enc2_C
AVPro
5002C
Dual SCART A/V Switch
3
TV RGB OUTPUTS
The device accepts RGB video signals from two
sources. The Aux_R, Aux_G, Aux_B input pins are
typically connected to the auxiliary SCART
connector. The Enc_R, Enc_G, Enc_B input pins are
connected to the RGB outputs of an external video
encoder device. These outputs are used as a video
source for the TV SCART pins TV_R, TV_G, and
TV_B. The RGB video source is selected by setting
the lower three (3) bits of serial port Register 1.
When these bits are set to xxxxxx00, the RGB
source will be the encoder. When these bits are set
to xxxxxx01, the source will be the auxiliary port. The
TV RGB outputs can be muted independently from
the TV composite outputs. Setting Bit 6 of Register 1
low (0) will allow normal operation. Setting Bit 6 high
(1) will set the TV RGB outputs to the blank level.
RGB Gain: The gain of the RGB outputs can be
adjusted to one of four different levels. Bits 4 and 5
in Register 2 set the gain of the RGB output
amplifiers according to the following table:
Bit 5
Bit 4
RGB Amplifier Gain
0
0
1
1
0
1
0
1
Gain = 2.0 V/V = A
0
Gain = A
0
- 10%
Gain = A
0
- 20%
Gain = A
0
- 30%
DC Restore: The device will generate a DC restore
level on each video output based on timing
referenced to a horizontal sync pulse. When the
sync pulse is detected, the DC restore circuit will act
to position the blank level to 0.6 V at the respective
video output load. The device can be programmed
to look for the horizontal sync pulse on all of the
RGB input pins or on the associated composite
video input pin (Aux_YC for the auxiliary port or
Enc_YC for the external encoder). Bit 7 of Register 1
determines the horizontal sync source. At power-up,
this bit defaults to a low (0) state which programs the
device to look for a sync detect on the RGB input
signals. In this mode, the device can detect a
horizontal sync on any of the three RGB input
signals. When Bit 7 is set to a high (1) state, the
device will look for a sync detect from the signal on
either the Aux_YC or Enc_YC pin depending on
which source is selected.
Blanking: The signal on the Blank output pin is
determined by the state of two MSBs in Register 2
according to the following table:
Bit 7
Bit 6
Blank source
0
0
1
1
0
1
0
1
BLANK = ABLANK
BLANK = EBLANK
BLANK = 0V
BLANK = 4V @ IC output pin
The user must insure that the source of the Blank
output is the same as the source for the RGB
outputs, i.e.ABLANK is selected when the auxiliary
RGB is active and EBLANK is selected when the
encoder RGB is active.
TV COMPOSITE OUTPUT
The device provides inputs for two composite video
sources that can be switched to the TV SCART
composite video pin, TV_YCout. The AUX_YC input
pin is typically connected to the "Video In" pin on the
auxiliary SCART connector. The Enc_YC input pin is
typically connected to the "YC" or "CVBS" output
from the external video encoder device. Selection of
the video source for the TV composite output is
accomplished when the RGB video source is
selected (see the register tables).
TV SVHS OUTPUT MODE
The device supports SVHS video format. The SVHS
mode is selected for the TV SCART using the lower
three (3) bits of Register 1. When the SVHS mode is
selected, the TV_YCout pin will provide the luminance
signal output from the selected source. The chroma
output will be provided on the TV_R pin. The video
source for SVHS mode can be either the auxiliary port
or the encoder port. When the auxiliary port is
selected as the video source, the video on Aux_R will
be provided at the TV_R output pin and the Aux_YC
video will be provided at the TV_YCout pin.
The device will support SVHS mode for three
encoder interface formats. The first encoder
interface format accepts chroma signals on the
Enc_C pin and luma signals on the Enc_Y pin. This
is designated "SVHS, Enc 1" mode. The second
format will receive chroma information on the Enc_B
pin and luma information on Enc_G. This format is
designated "SVHS, Enc 2". The third format will
receive chroma information from the Enc_R pin and
luma information from the Enc_G pin. This mode is
designated "SVHS, Enc 3".
When the SVHS mode is selected, the DC restore
on the TV_R pin will average to approximately 1.8
VDC at the output pin. The DC restore circuit will act
to position the blank level to 0.6 V at the TV_YCout
AVPro
5002C
Dual SCART A/V Switch
4
video output load. The TV_G and TV_B outputs will
be set to 0 VDC when the SVHS mode is active.
RF MODULATOR OUTPUT
The device provides an output, Mod_YC, to drive an
external RF modulator. The Mod_YC output is a
unity gain amplifier designed to drive a 1k load or
higher. When the device is operating in the RGB
mode, the signal on the Mod_YC output will follow
the same source as the RGB and TV_YCout
outputs.
When the device is in the SVHS mode, the Mod_YC
output can be driven by several sources depending
on the SVHS video source. These various options
are detailed in the serial port register table.
One case that requires additional detail is the
auxiliary SVHS mode. In the SVHS mode, the
Aux_YC video input will only provide luma
information. Composite video for the modulator
output must be generated by summing this luma
information with chroma information from the
auxiliary port. The input pin labeled Aux_Cin is used
for this purpose. The Aux_Cin input pin is AC
coupled to the same source that provides the input
signal to Aux_R. An internal summing node
combines the video signal on Aux_Cin (chroma) with
the video signal on Aux_YC (luma) to generate a
composite video signal. In the auxiliary SVHS mode,
this signal is provided at the Mod_YC pin.
TV COMPOSITE VIDEO MUTE
The TV composite video outputs can be muted by
programming the lower three (3) bits in Register 1.
The power-up default condition is xxxxx111, which
sets the TV composite video outputs to 0 VDC and
switches the TV audio outputs to Aux_Lin/Aux_Rin.
Setting these bits to xxxxx110 will also mute the TV
composite video outputs and switch the TV audio
outputs to Lin/Rin.
AUXILIARY COMPOSITE OUTPUT
The auxiliary port includes a composite video output
pin (AUX_YCout) that is typically connected to the
"Video Out" pin on an auxiliary SCART connector.
Bits 3-5 in Register 1 determine the source for the
AUX_YCout pin. When these bits are set to
xx000xxx, the video source will be the Enc_B input.
When these bits are set to xx001xxx, the video
source will be the Enc_YC input. When these bits
are set to xx010xxx, the video source will be the
TV_YCin input.
AUXILIARY SVHS OUTPUT MODE
In the SVHS mode, Pin 15 on the auxiliary SCART
connector provides chroma information. To support
this, the auxiliary port on the 5002C includes a
chroma input pin (Aux_Cin) that is externally AC
coupled to Pin 15 on the auxiliary SCART connector.
The device also includes an output pin (Aux_Cout)
that provides a chroma output to Pin 15 (RED) on
the auxiliary SCART connector. When connected
with the Aux_R and Aux_Cin pins, this forms a bi-
directional port as shown in the following diagram:
Bi-Directional Pin Circuit
Using this configuration, the device will support SVHS
mode for four encoder interface formats. The first
encoder interface format will receive chroma
information from the Enc_C pin and luma information
from the Enc_Y pin. This format is designated "SVHS,
Enc 1". The second format will receive chroma
information on the Enc_B input and luma information
on Enc_G. This format is designated "SVHS, Enc 2".
The third format will receive chroma information from
the Enc_R pin and luma information from the Enc_G
pin. This mode is designated "SVHS, Enc 3" on the
serial port register table. For these three modes,
audio will come from the Lin/Rin inputs. The fourth
format is designated "SVHS Enc 4". Chroma
information is received on the Enc2_C input pin and
the luma is received on the Enc2_Y input pin. For this
mode only, audio will come from the TV_Lin/TV_Rin
inputs.
When the SVHS mode is selected, the DC restore
on the Aux_Cout pin will average to approximately
0.9 VDC at the video output load. The DC restore on
the Aux_YCout pin will set the blank level to 1.2 V at
the IC pin or approximately 0.6 V across the video
output load.
Mux
Aux_R
Aux_Cout
Aux_Cin
62
Auxiliary
SCART
Pin 15
Mux
Mux
AVPro
5002C
Dual SCART A/V Switch
5
AUXILIARY VIDEO MUTE
All auxiliary video outputs can be simultaneously
disabled by programming Bits 3-5 in Register 1. The
power-up default condition is xx111xxx, which sets all
auxiliary video outputs to 0 VDC and switches the
auxiliary audio outputs to Lin/Rin.
FUNCTION SWITCHING
The device provides functions switching pins for both the
Auxiliary (Aux_Fnc ) and TV (TV_Fnc) SCART ports.
Both of these pins are bi-directional. The direction of the
pins is determined by setting bits in Register 2 according
to the following table:
Bits
Aux_Fnc
TV_Fnc
xxxx00xx
output
output
xxxx01xx
output
input
xxxx10xx
input
output
xxxx11xx
Passthru I/O
Passthru O/I
For the case where Register 2 is set to xxxx11xx, the
input signal on the Aux_Fnc pin is passed directly
through to the TV_Fnc pin as an output, or vice versa.
This mode is useful when the rest of the system powers
down and all signals from the auxiliary port are passed
directly through to the TV port, or vice versa.
When a function pin is set as an input, the voltage on that
pin is applied to an internal comparitor. The comparitor
senses the voltage on the input pin and sets the two (2)
LSBs in the read register according to the following table:
Input voltage
Bits
Function
< 4.0 V
xxxxxx00
Normal TV
4.0 to 8.0V
xxxxxx01
16:9 aspect
>8.0 V
xxxxxx10
Peritelevision
When a function pin is set as an output, the output level
for the pin is determined by the state of the two LSBs
Register 2, according to the following table:
Bits
Output voltage
Function
xxxxxx00
~0 V
Normal TV
xxxxxx01
~6 V
16:9 aspect
xxxxxx10
~ 11 V
Peritelevision
xxxxxx11
~ 11 V
Peritelevision
Note that both the Aux_Fnc pin and the TV_Fnc pin
can be set as outputs simultaneously, however they will
have the same output voltage.
The function output circuit includes short circuit
protection. When a function pin is in the 6V or 11V
output mode, if the SCART connection is shorted to
ground, then the output is disabled. Likewise, when a
function pin is in the 0V output mode, if the SCART
connection is connected to a voltage source, then the
output is disabled. The load for the function outputs is
designed to be 10k or higher.
Figure 2: 5002C Audio Switching Block Diagram
Aux_Rin
Aux_Lout
Mux
Aux_Rout
Aux_Mono
Mux
Mux
Mux
Aux_Lin
A
B
B
C
C
A: DAC Input Gain (0, 6, 9 or 11.6 dB)
B: Volume Control Gain (0 or 6 dB)
C: Volume Control Attentuation (0 to -31 dB in -1 dB steps)
A
Lin
Rin
Mux
Mux
TV_Rin
TV_Lin
Lout
TV_Lout
Mux
Mux
Mux
Mux
TV_Rout
Rout
Mux
Mux
Mod_mono
PDF 
ZIP