I previously posted in another thread about driving a TFT at 8bpp QVGA. My thought was to use Freescales MCF5227 with integrated LCD interface. My requirements have now changed to either 16 or 18 bpp. Rather than limit myself to a micro with integrated TFT interface I am looking at other options for controlling the TFT, SPI maybe? Have also been looking at doing it in software,ie, GPIO lines, extern mem interface. Just wondering what peoples thoughts are on driving the TFT this way as opposed to the integrated controller. What kind of processor overheads would i be looking at?
Driving TFT over SPI bus
Oct 30, 2008
1 Replies
Seems to me you have some relatively straightforward multiplication to do?
If the result of that looks plausible, it also seems like there should be nothing to prevent you from coding up the software and running it on an eval board, without actually building any of the display interface hardware. The one area where you might need hardware experiment would be to determine the minimum acceptable refresh rate.
In terms of chosing processors, at a minimum, I'd think you want a processor that can do fairly hands-off DMA of large amounts of data through the SPI at a fairly high clock rate, and with sufficient memory bandwidth to remain usable while this is going on in the background (assuming there's something else you need the processor to do... otherwise, read up on on the timex sinclair - in normal operation it only "computed" during vertical retrace, because the processor was programmatically driving the display the rest of the time)
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