LCD Refresh Rate

aditya23 · ‎2016-04-11

Posted on April 11, 2016 at 12:51

Hi,

I'm using a Discovery board with an STM32F469NI on it. I'd like to know more about how to set the LCD display refresh rate to a particular value. I've been through the spec sheet and reference manual and there's no direct setting so I need to learn what registers can be used to set it to a particular value (eg 800x480 @ 60 Hz).

Thanks.

#display #lcd

Tesla DeLorean · ‎2016-04-11

Posted on April 11, 2016 at 14:44

Try looking at the pixel clock, and work the math from there.

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aditya23 · ‎2016-04-11

Posted on April 11, 2016 at 15:44

Could you point me towards any reading material? ''Do the math'' doesn't help me when I don't really know what math there is to be done.

For what it's worth, I'm not expecting someone to do the calculations for me - the example I gave is not relevant to my code - but I'm really new to all this so I'd like to know a starting point and the path to take.

Tesla DeLorean · ‎2016-04-11

Posted on April 11, 2016 at 17:33

Well, you know how many pixels make up the image, and the clock at which those pixels are delivered, this would tend to provide a ceiling for the frame update rate. Factor in the front/back porches, and blank/framing lines.

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aditya23 · ‎2016-04-12

Posted on April 12, 2016 at 09:22

Oh okay, I think I get it. The width of the front and back porches... they're in pixels too? So I can just add the value to my existing resolution and that will be enough, I presume. Do I need to add the HSYNC and VSYNC width?