FPD87310 datasheet(22/28 Pages) NSC

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Appendix A: GPO (General

Purpose Output) Programming

Examples (Continued)

GPO Programming Example #4b:

Generate a control signal which transitions low 20 output

clocks after the beginning of each output line, has a pulse-

width (low) of 12 µs, and goes high during horizontal blank-

ing.

This control signal is used as an output enable for the Row

Drivers.

Based on 65 MHz XGA video, 1024 pixel/line,

768 lines/frame.

Horizontal time (clocks/line) = 1300 dot clocks.

Vertical period (lines/frame) = 850 lines.

Vertical control is active beginning at line #2 and remains ac-

tive for line #768.

GPO Vertical Start Register = 2 (0002

GPO Vertical Duration Register = 768 (0300

Negative pulse goes low each line at 20 output clocks after

first pixel data are outputted on R, G, B. Pulse remains low

for 780 output clocks (12 µs/15.38 ns = 780).

Note: 4 pixel counts are added to the output data start # because the GPO

pixel count begins 4 clocks prior to output data. (Shown as “

Figure 17

Internal Pixel Position Counter”.

GPO Horizontal Start Register = 24 (0018

GPO Horizontal Duration Register = 780 (030c

The controlled pulses are negative (bit[0] = “1”) and the

toggle circuitry is disabled (bit[1] = “0”).

GPO Control Register = 1 (01

H) (00000001B)

DS101077-26

FIGURE 23. Example #4b: GPO Vertical Scope View

DS101077-27

FIGURE 24. Example #4b: GPO Horizontal Scope View

FPD87310 Datasheet(PDF) 22 Page - National Semiconductor (TI)