Appendix A Scaling and I/0 Timing Register Calculations
CX25870/871
Flicker-Free Video Encoder with Ultrascale Technology
Table A-24. Overscan Values 1024 x 768 NTSC, Character Clock-Based Controller, 9-Pixel Resolution (2 of 2)
Controller Pixels
Total
Encoder Pixels
Overscan (Percent)
Active
Total
H_CLKI
V_LINESI
V_ACTIVEO
H_CLKO
Horizontal
Vertical
Delta
1260
1260
1260
1260
1260
1260
1260
1260
1260
1260
1260
1260
1260
1260
1260
1260
990
985
980
960
975
965
970
925
930
935
940
945
950
955
915
920
204
205
206
210
207
209
208
218
217
216
215
214
213
212
221
220
1584
1576
1568
1536
1560
1544
1552
1480
1488
1496
1504
1512
1520
1528
1464
1472
21.97
21.58
21.18
19.53
20.77
19.95
20.36
16.49
16.94
17.38
17.82
18.26
18.69
19.11
15.58
16.03
16.05
15.64
15.23
13.58
14.81
13.99
14.40
10.29
10.70
11.11
11.52
11.93
12.35
12.76
9.05
5.92
5.94
5.95
5.95
5.96
5.96
5.96
6.20
6.24
6.27
6.30
6.32
6.34
6.35
6.52
6.57
9.47
A-48
Conexant
100381B