I am developing an LCD controller, and some of the code for my (third-party) timing generator includes horizontal and vertical front/back porch and vsync/hsync pulse time information for a different LCD module.

The datasheet for the LCD I'm actually using has horizontal/vertical porch and pulse times, and these vary (in some cases substantially) from my third party code.

However, my understanding is that the porches, etc., really only matter for analog video, and that the data enable bit is the most important.

The sync pulses are where I'm a little hazy.

Is it likely to make any difference if I go back and edit the third-party timing generator code to use the same porch and pulse timings?


1 Answer 1


Of course timings matter even if using DE only. You must read the datasheets if there is a common range you can use for both, or if the current settings are good for both displays. Many displays ignore HSYNC/VSYNC and only use the DE so if both displays are only using DE then you should be fine. Better yet if the pixel clock, horizontal total and vertical totals are according to standards so you get a standard line rate and refresh rate.

  • \$\begingroup\$ I was looking at the wrong table. When using DE, the blanking and period times are jibe with the third-party values. It makes sense now, but it wasn't obvious from the janky Chinese datasheet what was being explained by the tables. \$\endgroup\$
    – Bort
    Sep 10, 2019 at 21:04
  • 1
    \$\begingroup\$ @schadjo I'd tell you to find something with a better datasheet, but I'm not sure LCD modules with good datasheets exist. \$\endgroup\$
    – Hearth
    Sep 11, 2019 at 13:30

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