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Thread: Slide Show now sends to PC

  1. #1
    Senior Member
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    Slide Show now sends to PC

    This is an improved Slide Show display. The QVGA slide images and transitions were recorded with the Win10 screen recorder. The slide images and transitions were sent to the PC host application using the T4.1 Dual serial connection so a dedicated USB channel was available for the image data. At the same time, the slide show was sent to an ILI9341 display. Sending to both at the same time dis not seem to slow the display significantly. Ah, the wonders of well-written drivers using DMA!

    https://youtu.be/PMQoLa-cA6s

    Now that I'm not limited to the QVGA resolution of the ILI93341, I plan to replace the .BMP file with full VGA versions and see how long it takes to do the transitions and display with 4 times as many pixels.

  2. #2
    Senior Member PaulStoffregen's Avatar
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    Just curious if any more info was ever published about this project?

    Did higher res files work?

    Is there any photo or video of how it looked on the display with Teensy?

  3. #3
    Senior Member
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    I did manage to get VGA-resolution BMP images sending to the PC. The transitions look OK, but the frame rate is noticeably slower. This is due to the 4 times larger number of pixels. The .bmp files have to be read pixel-by-pixel and converted to RGB565 as the Pixel Pipeline does not accept RGB888 data directly. The last version I had running in February did not do ILI9342 outrput but only sent the data to the PC.

    If I get the time over the next few weeks, I'd like to make the following changes:

    1. Read the slide show images once and convert to RGB565 bitmaps. For up to 8 slides, the RGB565 bitmaps could be held in extmem. For larger numbers of slides, the converted bitmaps could be written to SD card files. If there's a break or pause in transitions---as for a label, the file read and conversion could happen during that time.

    2. Figure out how to display on the ILI9341 at the same time I'm sending to the PC. This will require some fancy footwork by the PXP as it will have to switch from slide transitions to downscaling for the LCD with every frame. I'm not sure how much having to do two PXP operations per frame will affect the frame rate.

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