FPD87310 datasheet(21/28 Pages) NSC

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Appendix A: GPO (General Purpose Output) Programming Examples

(Continued)

GPO Programming Example #4a:

Generate a control signal which transitions high at end of

each line, has a pulse width of 0.5 µs, and remains low dur-

ing the vertical blanking period.

This control signal is used for latch pulse to the Column Driv-

ers.

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 #1 and remains ac-

tive for line #768.

GPO Vertical Start Register = 1 (0001

GPO Vertical Duration Register = 768 (0300

Positive pulse goes high each line at 1024 output clocks af-

ter last pixel are outputted on R, G, B.

Pulse remains high for 32 output clocks (0.5 µs/15.38 ns =

32.5).

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

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

Figure

17 “Internal Pixel Position Counter”.

GPO Horizontal Start Register = 1028 (0404

GPO Horizontal Duration Register = 32 (0020

The controlled pulses are positive (bit[0] = “0”) and the toggle

circuitry is disabled (bit[1] = “0”).

GPO Control Register = 0 (00

h) (00000000B)

DS101077-24

FIGURE 21. Example #4a: GPO Vertical Scope View

DS101077-25

FIGURE 22. Example #4a: GPO Horizontal Scope View

FPD87310 Datasheet(PDF) 21 Page - National Semiconductor (TI)