®
TDK SEMICONDUCTOR CORP.
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)
2
•
Serial port control of switching I C bus
•
64-lead LQFP package
BLOCK DIAGRAM
+12VDC
+5VDC
+5VDC
+5VDC
+5VDC
-5VDC
-5VDC
-5VDC
-5VDC
ABLANK
EBLANK
Aux_R
Enc_R
Enc_C
Aux_G
Enc_G
Aux_B
Enc_B
Enc2_Y
Enc2_C
Enc_Y
Enc_YC
Aux_YC
TV_YCin
Aux_Cin
SCLK
SDATA
Aux_Lin
Aux_Rin
Lin
Rin
TV_Lin
TV_Rin
Rbias
Vref
Tgen
Other I/O
Serial
Port
BLANK
TV_R
TV_G
TV_B
TV_YCout
Mux
Mod_YC
Aux_Cout
Aux_YCout
Aux_Fnc
TV_Fnc
DO_0
DO_1
Rout
Lout
TV_Rout
TV_Lout
Mod_mono
Aux_Lout
Aux_Rout
Aux_Mono
Volume
Control
Mux
Support
Circuits
GND
GND
GND
GND
AVPro
®
5002C
Dual SCART A/V Switch
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
2
the device are controlled through a standard I C
serial interface and a set of internal registers.
The device
encoder that
the 5002C
outputs and
audio/video.
will interface to an external video
provides six video outputs. In addition,
includes two programmable digital
provides inputs for the TV SCART
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”.
2V
ABLANK
EBLANK
Aux_R
Enc_R
Enc_C
Enc2_C
Gain
0V
Mux
BLANK
Mux
TV_R
Mux
Aux_G
Enc_G
Aux_B
Enc_B
Enc_Y
Enc_YC
Aux_Cout
Mux
Mux
Mux
TV_G
TV_B
TV_YCout
Mux
TV_YCin
Enc2_Y
Aux_YC
Aux_Cin
Aux_Fnc
Comparator
VGen
Mux
Aux_YCout
Mux
Mod_YC
TV_Fnc
Figure 1: 5002C Video switching block diagram
2
AVPro
®
5002C
Dual SCART A/V Switch
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
0
0
1
1
Bit 4
0
1
0
1
RGB Amplifier Gain
Gain = 2.0 V/V = A
0
Gain = A
0
- 10%
Gain = A
0
- 20%
Gain = A
0
- 30%
Bit 7
0
0
1
1
Bit 6
0
1
0
1
Blank
source
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
3
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:
AVPro
®
5002C
Dual SCART A/V Switch
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 (
ux_Cout)
A
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:
Aux_Cout
Mux
Aux_R
Mux
Aux_Cin
Mux
62
Auxiliary
SCART
Pin 15
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.
4
AVPro
®
5002C
Dual SCART A/V Switch
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
xxxx00xx
xxxx01xx
xxxx10xx
xxxx11xx
Aux_Fnc
output
output
input
Passthru I/O
TV_Fnc
output
input
output
Passthru O/I
LSBs in the read register according to the following table:
Input voltage
< 4.0 V
4.0 to 8.0V
>8.0 V
Bits
xxxxxx00
xxxxxx01
xxxxxx10
Function
Normal TV
16:9 aspect
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
xxxxxx00
xxxxxx01
xxxxxx10
xxxxxx11
Output voltage
~0 V
~6 V
~ 11 V
~ 11 V
Function
Normal TV
16:9 aspect
Peritelevision
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.
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)
TV_Lin
Mux
Mux
Aux_Lout
Aux_Mono
TV_Rin
Mux
Mux
Aux_Rout
Mux
A
Lin
Mux
Aux_Lin
A
Rin
Mux
Aux_Rin
Mux
Mux
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)
Mux
B
C
B
C
Mux
Mux
Lout
TV_Lout
Mod_mono
TV_Rout
Rout
Figure 2: 5002C Audio Switching Block Diagram
5
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