LM1253A National Semiconductor, LM1253A Datasheet - Page 50

• Manufacturer Part Number: LM1253A
• Description: Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator
• Manufacturer: National Semiconductor

Control Register Definitions
(Continued)
In the LM1253A, an approximation method is used to determine which lines are repeated, and how many times each line is re-
peated.
The constant character height mechanism will not decrease the OSD character matrix to less than 18 lines. Each character will
be at least 18 lines high.
Display Window 1 To Display Window 2 Spacing
There is no required vertical spacing between Display Window 1 and Display Window 2, but they should not overlap.
There must be a two character horizontal space between Display Window 1 and Display Window 2 for proper operation of both
windows or undefined results may occur.
Evaluation Character Fonts
The character font of the LM1253A is shown in Figures 45, 46, 47, 48, 49, 50 .
Note that the first two character codes of the two color font (00h and 01h) are reserved for the Window End (WE) and Row End
(RE) codes respectively.
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