tda9112a STMicroelectronics, tda9112a Datasheet - Page 34

• Manufacturer Part Number: tda9112a
• Description: High-end I2c Controlled Deflection Processor For Multisync Monitor
• Manufacturer: STMicroelectronics

TDA9112A
VExtrDet, VPol, HVPol). The device is equipped
with an automatic mode (switched on or off by
VSyncAuto
tion information.
Figure 2. Horizontal sync signal
Figure 3. Extraction of V-sync signal from H/V-sync signal
9.2.3
I²C-bus bit
the polarity and signal presence detection flags,
after setting the
priate delay, to obtain a true information of the sig-
nals applied, reads and evaluates this information
and controls the vertical signal selector according-
ly. The MCU has no access to polarity inverters,
they are controlled automatically.
See also chapter
34/60
Integration
H/V-sync
Extracted
Internal
V-sync
MCU controlled sync. selection mode
VSyncAuto
I²C-bus bit) that also uses the detec-
SDetReset
Chapter 8 - page 27
Positive
Negative
T
H
T
is set to 0. The MCU reads
H
bit to 1 and an appro-
tPulseHSyn
.
tPulseHSyn
textrV
9.2.2
The sync. signal presence detection flags in the
status register (VDet, HVDet, VExtrDet) do not
show in real time the presence or absence of cor-
responding sync. signal. They are latched to 1 as
soon as a single sync. pulse is detected. In order
to reset them to 0 (all at once), a 1 must be written
into
effect with ACK bit of the I²C-bus transfer to the
register containing
circuits are ready to capture another event (pulse).
See
9.2.4
I²C-bus bit
device itself controls the I²C-bus bits switching the
polarity inverters (HVPol, VPol) and the vertical
sync. signal selector (VSyncSel), using the infor-
mation provided by the detection circuitry. If both
extracted and pure vertical sync. signals are
present, the one already selected is maintained.
No intervention of the MCU is necessary.
SDetReset
Note 68
Sync. presence detection flags
Automatic sync. selection mode
VSyncAuto
.
I²C-bus bit, the reset action taking
SDetReset
is set to 1. In this mode, the
bit. The detection