> I'm looking at driving an 800x400 LCD over USB. I could do this with a
> PIC32 controllerless LCD (PMP or EBI DMA) system, but it appears I need a
> frame buffer. For more than 8 bits per pixel, the frame buffer does not
> fit on the chip, and costs start going up.
>
> In another product, we're sending video over several LVDS pairs to an LVD=
S
> to LCD interface chip. That works well there, but the new processor does
> not have the LVDS lines available. So, we're looking at USB.
>
> It SEEMS that there would similarly be a USB to RGB LCD controller chip
> that does not have or need a frame buffer. Instead, the pixels would just
> be streamed over USB and sent to the LCD.
>
> Anyone know of such a chip?

Following up on my own post, an idea that comes to mind with the use of
the PIC32 controllerless LCD system is to only buffer a line at a time.
The USB could DMA into one line buffer while another line buffer is sent
to the LCD. If the LCD is a little faster than the USB, it can wait for
the USB DMA to fill, then swap buffers. Does something like that sound
practical? I'm not seeing the need to buffer the whole frame. Can anyone
point to what documentation as to what USB video would look like coming
out of the Microchip USB interface?

Thanks!

Harold



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