Datasheet

Table Of Contents
ADV7188
Rev. A | Page 13 of 112
ANALOG INPUT MUXING
The ADV7188 has an integrated analog muxing section that
allows connecting more than one source of video signal to the
decoder.
Figure 6 outlines the overall structure of the input
muxing provided in the ADV7188.
As can be seen in
Figure 6, the analog input muxes can be
controlled in two ways:
By the functional register (INSEL). Using INSEL [3:0]
simplifies the setup of the muxes and minimizes crosstalk
between channels by preassigning the input channels. This is
referred to as the recommended input muxing.
By an I
2
C manual override (ADC_SW_MAN_EN,
ADC0_SW, ADC1_SW, ADC2_SW, and ADC3_SW). This
is provided for applications with special requirements, such
as number/combinations of signals that are not served by
the preassigned input connections. This is referred to as
manual input muxing.
Figure 7 shows an overview of the two methods of controlling
input muxing.
05478-007
SET INSEL[3:0] TO
CONFIGURE ADV7188
TO DECODE VIDEO FORMAT:
CVBS: 0000
Y/C: 0110
YPrPb: 1001
SCART (CVBS/RGB): 1111
SET SDM_SEL[1:0] FOR
S-VIDEO/COMPOSITE
AUTODETECT
USE MANUAL INPUT MUXING
(ADC_SW_MAN_EN, ADC0_SW,
ADC1_SW, ADC2_SW,
ADC3_SW)
SET INSEL[3:0] AND
SDM_SEL[1:0]
FOR REQUIRED MUXING
CONFIGURATION
CONNECTING
ANALOG SIGNALS
TO ADV7188
RECOMMENDED
INPUT MUXING;
SEE TABLE 8 AND TABLE 9?
NO
YES
Figure 7. Input Muxing Overview
Recommended Input Muxing
A maximum of 12 CVBS inputs can be connected and decoded
by the ADV7188, meaning that the sources must be connected
to adjacent pins on the IC, as seen in
Figure 5. This calls for a
careful design of the PCB layout, for example, placing ground
shielding between all signals routed through tracks that are
physically close together.
SDM_SEL [1:0], Y/C and CVBS Autodetect Mode Select,
Address 0x69 [1:0]
The SDM_SEL bits decide on input routing and whether
INSEL [3:0] is used to govern input routing decisions.
The S-video/composite autodetection feature is enabled using
SDM_SEL = 11.
Table 8. SDM_SEL [1:0]
SDM_SEL [1:0] Mode Analog Video Inputs
00 As per INSEL [3:0] As per INSEL [3:0]
01 CVBS AIN11
10 Y/C
Y = AIN10
C = AIN12
11
S-video/composite
autodetection
CVBS = AIN11
Y = AIN11
C = AIN12