Appendix A Scaling and I/0 Timing Register Calculations
CX25870/871
Flicker-Free Video Encoder with Ultrascale Technology
Table A-4. Overscan Values, 640 x 480 NTSC, Pixel-Based Controller, 1-Pixel Resolution, 2.5 µs HBlank (1 of 2)
Controller Pixels
Total
Encoder Pixels
Overscan (Percent)
Active
Total
H_CLKI
V_LINESI
V_ACTIVEO
H_CLKO
Horizontal
Vertical
Resolution
780
780
784
780
777
785
777
777
775
775
777
775
775
790
791
770
770
770
770
770
795
770
795
765
798
798
798
800
765
765
800
665
595
600
630
575
630
625
650
588
651
600
609
630
630
600
645
585
660
615
630
630
600
595
665
650
600
625
630
630
595
609
190
212
210
200
220
200
202
194
215
194
210
207
200
200
210
196
216
191
205
200
200
210
212
190
194
210
202
200
200
212
207
988
884
896
936
851
942
925
962
868
961
888
899
930
948
904
946
858
968
902
924
954
880
901
969
988
912
950
960
918
867
928
21.81
12.61
13.79
17.47
9.23
21.81
12.76
13.58
17.70
9.47
0.00
–0.14
0.21
–0.23
–0.24
0.30
18.00
16.49
19.70
11.00
19.62
13.01
14.07
16.94
18.51
14.55
18.34
9.97
17.70
16.87
20.16
11.52
20.16
13.58
14.81
17.70
17.70
13.58
19.34
11.11
21.40
15.64
17.70
17.70
13.58
12.76
21.81
20.16
13.58
16.87
17.70
17.70
12.76
14.81
–0.38
–0.46
–0.52
–0.55
–0.57
–0.74
–0.76
0.82
0.97
–1.00
–1.14
–1.20
–1.28
–1.30
1.33
20.20
14.36
16.40
19.03
12.22
14.26
20.28
21.81
15.30
18.69
19.53
15.85
10.90
16.76
–1.36
1.51
–1.53
1.65
1.72
1.81
1.84
–1.84
–1.86
1.94
A-12
Conexant
100381B
CONEXANT [ CONEXANT SYSTEMS, INC ]
