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  • Fast(er) refresh rates / draws?

    I've seen some threads here suggesting that one can obtain high variable refresh rates:

    http://4d.websitetoolbox.com/post/refresh-rate-3249067?highlight=refresh

    For GOLDELOX, frame rate is adjusted from 75 to 150FPS using CLOCK_DIV FR[3:0]

    - does use of start line/duty ratio to limit display update have any effect on frame rate?

    Thank you for any details or suggestions.
    I'm not entirely sure what this person was referencing as I saw nothing about CLOCK_DIV in any of the datasheets I've been looking at.

    Is this actually possible? And if so, it's not exactly clear to me how one might achieve this.

    This aside, are there any ways to get fast-updates to these displays on the order of said 75-150 FPS? For example, if I only actually ever need to update a few tens of pixels at a time. I have 4D-display-shield-128, and have been playing around with 4DGL (doesn't seem capable of doing this?), but haven't touched SGC quite yet.

    Also, please pardon any naivety on my part - I have little experience working with displays.

  • #2


    The post you are referring to is talking about the refresh rate, or the number of times a second the display glass is updated from the memory contained within the display glass (which is totally different to the memory within the Goldelox processor).

    From memory most of the oled displays are set to about 110hz. This is to enable optimum display brightness, and will probably mean if you upped the rate further the display would dim.

    Why do you want to get such high rates? The human eye certainly cannot discern such rates.

    Say the FPS rate from uSD was 11fps, if you only updated half the screen the fps rate would wouble to 22, for 1/4 of the screen it would double again.

    Of course, that's from uSD, if the data is coming from the COM port you will be restricted the the baud rate.

    Have a look at disp_BlitPixelsFromCOM() command, it shows you both how to focus on a portion of the screen and how to update it 'continuously' from the COM port. Note that it also shows how to update 2 pixels (with reduced color depth) for each byte, rather than the 'more normal' 1 pixel per 2 bytes.
    Mark

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    • #3


      Why do you want to get such high rates? The human eye certainly cannot discern such rates.
      So while flicker fusion occurs around ~15-30fps, there are actually other visual artifacts which can be detected at **much** higher FPS (also, despite integrated motion, flicker can still be detected at higher FPSs) due to either the viewing environment and even neurological conditions. So - there are actually things to be studied at much higher FPSes (as that poster I linked to mentioned). I would be more specific, but my group isn't quite ready to go public yet with what we're working on.

      Say the FPS rate from uSD was 11fps, if you only updated half the screen the fps rate would wouble to 22, for 1/4 of the screen it would double again.
      Gotcha! What should I look to for a reference on updating portions of the screen from the uSD?/do you know of any examples built into the IDE that do this? Would this be in the 4DGL programming reference?

      Have a look at disp_BlitPixelsFromCOM() command, it shows you both how to focus on a portion of the screen and how to update it 'continuously' from the COM port. Note that it also shows how to update 2 pixels (with reduced color depth) for each byte, rather than the 'more normal' 1 pixel per 2 bytes.
      Will do!

      Thanks!

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