MGA to VGA adapter

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Hi, I am making an adapter to convert a monochrome graphics adapter output to VGA 800 x 600 resolution. I found the easiest (for me) route is to use two micro-controllers, one to read the MGA video and one to write the VGA output because of the vast differences in timing and the need to keep both timings stable. I believe an XmegaE will be fast enough to read the MGA but it will need an UC3 to write the VGA. Basic operation is to read each line (720 pixels) and write it to a 32K x 16 sram during the retrace (front porch, hsync, back porch time). Meanwhile, the UC3 is reading from a second SRAM and outputing the VGA signals. At the end of a frame the UC3 is signaled to switch SRAMs and the XmegaE starts writing to the second SRAM. A mutliplexer switch changes which SRAM connects to which uC. The output foreground/background RGB values are controlled by pots connected to an ADG733 SPDT analog switch. Attached is a general diagram of the system. Any comments would be appreciated.

 

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Last Edited: Mon. Sep 22, 2014 - 12:00 PM