Appendix A Scaling and I/0 Timing Register Calculations
CX25870/871
Flicker-Free Video Encoder with Ultrascale Technology
Table A-22. Overscan Values 1024 x 768 NTSC, Pixel-Based Controller, 1-Pixel Resolution, >1.50 µs. Hblank (1 of 4)
Graphics Controller
Total
Encoder Pixels
Overscan (Percent)
Active
Total
H_CLKI
V_LINESI
V_ACTIVEO
H_CLKO
Horizontal
Vertical
Delta
1173
1170
1170
1170
1175
1176
1170
1176
1165
1179
1175
1167
1182
1164
1160
1180
1185
1161
1188
1158
1155
1155
1155
1185
1155
1155
1190
1155
1155
1155
1190
1050
945
192
214
199
206
200
192
192
207
214
192
214
192
192
192
214
214
192
192
192
192
214
201
198
214
204
195
195
192
207
217
204
1564
1404
1508
1456
1504
1568
1560
1456
1398
1572
1410
1556
1576
1552
1392
1416
1580
1548
1584
1544
1386
1474
1496
1422
1452
1518
1564
1540
1430
1364
1496
20.97
11.97
18.04
15.11
17.82
21.18
20.77
15.11
11.59
21.38
12.34
20.57
21.58
20.36
11.21
12.71
21.77
20.16
21.97
19.95
10.82
16.15
17.38
13.08
14.88
18.58
20.97
19.74
13.57
9.39
20.99
11.93
18.11
15.23
17.7
-0.01
0.03
1015
980
-0.07
-0.11
0.13
1008
1050
1050
975
20.99
20.99
14.81
11.93
20.99
11.93
20.99
20.99
20.99
11.93
11.93
20.99
20.99
20.99
20.99
11.93
17.28
18.52
11.93
16.05
19.75
19.75
20.99
14.81
10.7
0.19
-0.22
0.3
945
-0.34
0.39
1050
945
0.41
1050
1050
1050
945
-0.42
0.59
-0.63
-0.73
0.78
945
1050
1050
1050
1050
945
0.79
-0.83
0.98
-1.04
-1.11
-1.14
-1.14
1.15
1005
1020
945
990
-1.17
-1.17
1.22
1035
1035
1050
975
-1.25
-1.25
-1.31
1.33
930
990
17.38
16.05
A-42
Conexant
100381B
CONEXANT [ CONEXANT SYSTEMS, INC ]
