TDA9106A View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'TDA9106A' PDF : 30 Pages View PDF
TDA9106A
OPERATING DESCRIPTION (continued)
I.6 - Sync Identification Status
TDA9106Ais able to feed back to the MCU (thanks
to I2C) the Sync input status (sync identification) so
that the MCU can chooseSync priority throughI2C.
As extracted Vertical sync pulse is performedwhen
choice already occured and when 12V is supplied,
we recommend to use the deviceas following :(that
means that even in Power management mode the
IC is able to inform MCU on detected synchro
signals due to its 5V supply).
First, refresh Synchrodetection by I2C. Then check
the status of H/V det and Vdet by I2C read.
Sync priority choice should be :
Table 1 : Sync Priority Choice
H/V det
Yes
Yes
No
V det
Yes
No
No
Sync priority
Subaddress 03
D8
D7
1
1
0
1
0
0
Comment
Synchro type
Separated H & V
Composite TTL
H&V
Sync on Green
Of course, when choice is done, one can refresh
the synchro detections and verify that extracted
Vsync is present and that no synchro type change
occured.
Synchro processor is also giving synchro polarity
information.
I.7 - IC status
TheIC can inform the MCUeither the 1st Horizontal
PLLor Vertical sectionare locked or not, and if Xray
has been activated.
This last status permits to the MCU :
- reset the Xray internal latch decreasing the VCC
supply
- directly reset throw the I2C interface.
I.8 - Synchro Inputs
Both H/HVin and Vsyncin inputs are TTL compat-
ible trigger with Hysterisis to avoid erratic detection.
It includes pull up resistor to VDD.
Vertical sync extractor is included for composite
sync or composite video.Applicationengineer must
adapt resistor R and capacitor C dedicated to its
application.
Figure 5
R
C S/G 1kΩ
1
TDA9106
1.6V
IREF (Typ.)
= 10µA
Resistor R is fixed by detection threshold wanted :
R < (VTHRESHOLD / IREF)
Then C is determined by maximum pulse width to
detect (in general, vertical sync width) :
RC > (max pulse width)
I.9 - Synchro Processor Outputs
Synchro processor delivers on 3 TTL-compatible
CMOS outputs the following signals :
- Hout as follow :
Sync Mode
Separated
TTL Composite
S/G
Hout Mode
Horizontal
TTL Composite
Composite
Hout Polarity
Same as Input
Same as Input
Negative
- Vsyncout is either vertical extracted pulse output
or Vsyncin input. It keeps the input polarity.
- Hlockoutis theHorizontal1st PLLstatus: 0Vwhen
locked. It permits MCU to adjust free running
frequency and optimizes the IC performance.
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