W90221X Winbond Electronics Corp America, W90221X Datasheet - Page 28

• Manufacturer Part Number: W90221X
• Description: Pa-risc Embedded Controller
• Manufacturer: Winbond Electronics Corp America

VSO (output)
¨
VREF (analog Out) (optional)
COMP (analog Out)
RSET (analog Out)
EXTVREF (analog In) (optional)
TVDD, TVSS
5.7.5 Application Notes
A digital camera, or an NTSC/PAL camera connected to a TV decoder is fed into the
W90221X in YCbCr 4:2:2 format through 8-bit data bus(VIN[0:7]). The input video is cropped
and scaled, then display to output device. During operation mode, VCC[22] of VPRE must be
set to zero to control data bus direction. And control data stream format by VCC[26:27] of
VPRE.
The following figures show some typical timing diagrams of VPRE input pins:
Figure 5.7.5.1 VPRE timing diagram
W90221X version 0.6
DAC interface
Horizontal sync of the displayed graphic output: The content of VAconf[?] determines
the polarity of this signal.
Vertical sync of the displayed graphic output: The content of VAconf[?] determines the
polarity of this signal.
Voltage Reference Out; Bypass and decouple the voltage reference with 0.1uF ceramic
capacitor to the TVDD. The decoupling capacitor shall be as close to the chip as
possible. This pin as well as "COMP" are used to control the current of internal current
sources are exactly equal to "Iref".
Compensation pin: It shall be decoupled with a 0.1uF ceramic capacitor to TVDD. The
decoupling capacitor shall be as close to the chip as possible.
Current source adjusting resistor: This pin is used to adjust the full-scale current of TV's
analog outputs. A resistor shall be connected between this pin and TVSS. (The DAC's
"Iref" current mirrors are adjusted by this pin). The Iref is approximate to 1.16V/RSET.
External Vref input. This signal supplies the DAC's "bandgap" output from a external
1.235V voltage source. A 0.1uF bypass capacitor should be always connected between
this pin and TVDD. ("bandgap" is an voltage stabilizer of voltage-reference-generator
"Vref").
Dedicate power/ground pins for internal DACs.
I N P U T
H S I , V S I ,
V I N [ 0 : 7 ]
S y m b o l
T h
T s u
V C L K
Parameter
VIN[0:7], HSI, VSI
VIN[0:7], HSI, VSI
Input Timing AC Characteristics
1 . 5 V
M i n
5
5
T s u
1 . 5 V
input valid
M a x
T h
Unit
ns
ns
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