8051 to DVI interface?
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From: msg on 12 Feb 2007 12:21 Guy Macon wrote: > jasen wrote: >>how about an 8-bit VGA card? > > > Hmmm. No acual ISA cards on the market nowdays, but there > are PC104 cards. A 8051 to PC104 interface might do it. > I am always astounded by the lack of interest in component re-use as found in so many posts in this newsgroup; there are _scads_ of ISA VGA cards around in every berg on the planet and even in rural waste transfer stations; drive down any alley in a town of more than one stoplight and you are bound to find PCs which are likely to contain an ISA VGA card (8 or 16-bit useable in 8-bit mode). For a 'small volume' application coming up with even hundreds of ISA VGA cards should present less of a logistics problem than specifying some currently marketed solution. Our local metal recycler has a gaylord with at least that many at any given instant in time. Regards, Michael
From: larwe on 12 Feb 2007 12:27 On Feb 12, 11:37 am, Guy Macon <http://www.guymacon.com/> wrote: > I am still thinking that a counter clocking data out of > RAM can make a VDI signal. I agree this sounds doable, but I would not expect this system to work unless you are delivering at minimum VGA scanrates. A method I used to drive an LCD (not DVI) "directly" from an 8051 was to embed the sync signal in spare RAM bits; i.e. I used two bits each for r,g,b in a x8 SRAM and put the v-sync and h-sync bits in the remaining bits. The v-sync bit caused a micro interrupt; the micro then held v-sync active while resetting the counter that addressed the video RAM. (Actually it was a bit more complex than this - the micro tristated the counter and held the v-sync active, then if necessary wiggled the address/data bus on the RAM to update display data). Your intermediate divider and base dot clock will depend on what resolution you want to use to drive the display. You will probably also want to add extra logic so that you can reuse scanline data; i.e. have separate scanline and dot position counters and ignore the lower bits. Let's try to work some nice numbers into this. Start with a 32kHz horz sync, since it's a nice round number. You need to supply a v-sync pulse every 480 lines, which is 15ms (66.67Hz).
From: Guy Macon on 12 Feb 2007 12:46 Guy Macon <http://www.guymacon.com/> wrote: >I am working on an 8051-based project that needs a >display. Normally I would just use a small character- >based LCD display, but in this case I am thinking of >going with something a bit more impressive; a standard >flat-panel PC monitor. Here are the results of my resarch so far: This fellow did 20 rows by 20 columns of 8x12 characters using a 16MHz AVR.: http://www.serasidis.gr/circuits/AVR_VGA/avr_vga.htm ...and a simle colorbar generator: http://www.serasidis.gr/circuits/colour_bar_gen/colour_bar_gen.htm If a 16Mhz. AVR can do that, what can a 100mips Cignal C8051F120 do? A OMAP5910 might have potential: http://focus.ti.com/lit/an/spra847/spra847.pdf Or maybe this TVT-KVGA: http://www.tvterminal.de/Flyer_TVT_KVGA_international_070129.pdf The Parallax Propeller appears to have some sort of "video object": http://www.parallax.com/propeller/index.asp Or maybe a Xlinnx XC4005XL? http://www.ece.umr.edu/courses/cpe214/vga_datasheet.pdf Or I could go with good old DonTronics: http://www.dontronics-shop.com/product.php?productid=16388&cat=262&page=1 Any thoughts on any of the above? Guy Macon <http://www.guymacon.com/>
From: Andy Peters on 12 Feb 2007 13:16 On Feb 12, 10:46 am, Guy Macon <http://www.guymacon.com/> wrote: > Or maybe a Xlinnx XC4005XL?http://www.ece.umr.edu/courses/cpe214/vga_datasheet.pdf XC4K parts are old and expensive and probably hard to get. Go with a Spartan3 part. -a
From: Jim Granville on 12 Feb 2007 13:57
Guy Macon wrote: > > I am still thinking that a counter clocking data out of > RAM can make a VDI signal. Yes, it could. You could use a fast uC, and then a TS counter like the HC590, to clock the line pixels, and INT the uC at line ends, so the processor runs < line speeds. If you are ok with 256n clocks across the screen, then uC resource like the PCA in the SiLabs parts, would manage blanking and any resets needed. DRAM would be interesting, but perhaps not a very stable target. -jg |