S5D2650 Samsung Semiconductor, Inc., S5D2650 Datasheet - Page 9

• Manufacturer Part Number: S5D2650
• Description: Multistandard Video Decoder/scaler
• Manufacturer: Samsung Semiconductor, Inc.

S5D2650 Data Sheet
frequency signal reduction. This can be implemented with a 400 pF capacitor in parallel with the 75 Ω load.
1.1.2. Digital AGC Control
The AGC normally references to the ADC code difference between sync tip and back porch. Two sets of sync
tip-back porch ADC values are available for different AGC gain requirements: if AGCGN = 0, the sync tip locks to
code 2, and the back porch locks to code 70; when AGCGN = 1, the sync tip locks to 16, and the back porch locks
to code 70. Video signal with abnormal sync tip or very bright saturated colors may cause the ADC to limit the
maximum value. This situation can be corrected by enabling the AGCOVF bit in the CMDB register to force the
gain tracking loop to reduce AGC when maximum limiting conditions occur. The AGC may also be programmed to
freeze the AGC at the current value by setting the AGCFRZ bit in the CMDB register. Once the AGC is frozen, the
gain can be manually adjusted with the AGC register. The tracking time constant for the AGC can be controlled
with the AGC_LPG[1:0] bits in the TRACKB register. In addition, the AGC tracking time constant can be
configured as 2X faster during acquisition via the AGC_LKG.
1.1.3. Digital Video Input
The high quality digital video down scaler in the S5D2650 can be directly accessed via the EXV bi-directional port.
The S5D2650 accepts CCIR 656 compliant 8-bit YCbCr digital video input with embedded or external HS, VS
timing. Video timing may also be generated by the S5D2650. Data path for 8-bit YCbCr input is shown in Figure 3.
Selection of analog video input or digital CCIR 656 data is with the INPSL[1:0] register bits.
ELECTRONICS
INSEL[2:0](hex)
0
1
2
3
4
5
6
7
Table 1: Analog Video Input selections
Analog
Video
Figure 2.
Selected Input(s)
AY0,ACB0,ACR0
AY1,ACB1,ACR1
AY0,ACB0
AY1,ACB1
75 Ω
ACR0
ACR1
Typical Analog Video Input
AY0
AY1
0.1 µF
YPbPr component video
YPbPr component video
S5D2650
Video Type
Composite
Composite
Composite
Composite
S-Video
S-Video
MULTIMEDIA VIDEO
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7/18/03