8051 to DVI interface?
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From: martin griffith on 11 Feb 2007 13:32 On Sun, 11 Feb 2007 17:06:01 +0000, in comp.arch.embedded Guy Macon <http://www.guymacon.com/> wrote: > > > >Jim Granville wrote: > >>If you need CHAR only (no pictures), then our Vga-232 modules >>would suit this very well. >>see http://www.designtools.co.nz/vga_232.htm >> >>This is designed to sit in usage between monochrome CHAR based LCD modules, >>and full Graphics/Pictures Embedded PC apps. >>Interface is a superset-variant of the old ANSI escape controls, >>(Adds Colour and Font/Scale controls), over a simple serial link. > >Interesting! > >Is "Full 16 Colour, 640 x 400 Pixel VGA Display" a typo? > >Could you have meant 640x480 or perhaps 720x400? > >How do you generate the VGA signals? > > > > something like this? http://www.gennum.com/video/products/gs4911b_gs4910b.htm martin
From: Jim Granville on 11 Feb 2007 13:46 Guy Macon wrote: > Jim Granville wrote: > > >>If you need CHAR only (no pictures), then our Vga-232 modules >>would suit this very well. >>see http://www.designtools.co.nz/vga_232.htm >> >>This is designed to sit in usage between monochrome CHAR based LCD modules, >>and full Graphics/Pictures Embedded PC apps. >>Interface is a superset-variant of the old ANSI escape controls, >>(Adds Colour and Font/Scale controls), over a simple serial link. > > > Interesting! > > Is "Full 16 Colour, 640 x 400 Pixel VGA Display" a typo? > > Could you have meant 640x480 or perhaps 720x400? No - Vga text mode (all PCs boot in this first), is 80x25 lines, of 8x16 pixel chars, so that's 640x400. 640x480 just bumps over a standard RAM boundary. > How do you generate the VGA signals? Frame and line sync are relatively easy, just chains of dividers in a CPLD. Dual port RAM access is more complex, but you can just access in flyback times for a simpler system, a la first generation PCs. First generation PCs, (like the 6845) also used a character Font ROM, and they can get by with much less RAM (back then, RAM was expensive), plus you could not run early RAM at pixel-clock speeds. If monochrome is OK, a few of the latest uC can do reasonable pixel rates out of their SPI ports - not quite 2000 chars on a screen, but some hundreds is doable. -jg
From: Jim Granville on 11 Feb 2007 13:54 larwe wrote: > > In summary, it took me two days to build and download "hello world!". > Having example code on the disk that ALL requires further buyware > cores is stupid, IMHO - people need to have a working build > environment so they can use it as a basis for their own projects. Did you feed that back to Xilinx ? Typically this outcome stems from simple laziness to test their systems fully : as most of their PCs will have all the fruit, they _think_ it all works fine..... Working sample code is a great learning platform, (and it has to cut support bandwidth), so it's surprising how many vendors do a poor job here. -jg
From: jasen on 12 Feb 2007 01:35 On 2007-02-11, Guy Macon <"http://www.guymacon.com/"@example.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. > > This is a small-volume project with no particular cost, > space, environmental or power constraints. The display > is mostly static with a few small areas that change > infrequently. 640x480 would be acceptable, but 1024x768 > would be a lot easier to find monitors for. I am also > willing to spring for a fast 100 Mips 8051 if that will > help. > > My first thought was having a counter clock data out of > fast RAM into DACS and thus make a VGA signal, with the > 8051 updating another bank of RAM and making a fast bank > switch during vertical retrace, but then I started > thinking about DVI interfaces. Normally a PC throws a > lot of fast data at a DVI interface, but would it hold > a static picture with a much slower refresh rate? Or > could I run RAM fast enough to hit a 60Hz refresh? > > Another possibility would be some sort of display chip; > does anyone know of one suitable for a slow 8-bit micro? how about an 8-bit VGA card? Bye. Jasen
From: Guy Macon on 12 Feb 2007 11:37
jasen wrote: > >Guy Macon <"http://www.guymacon.com/"@example.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. >> >> This is a small-volume project with no particular cost, >> space, environmental or power constraints. The display >> is mostly static with a few small areas that change >> infrequently. 640x480 would be acceptable, but 1024x768 >> would be a lot easier to find monitors for. I am also >> willing to spring for a fast 100 Mips 8051 if that will >> help. >> >> My first thought was having a counter clock data out of >> fast RAM into DACS and thus make a VGA signal, with the >> 8051 updating another bank of RAM and making a fast bank >> switch during vertical retrace, but then I started >> thinking about DVI interfaces. Normally a PC throws a >> lot of fast data at a DVI interface, but would it hold >> a static picture with a much slower refresh rate? Or >> could I run RAM fast enough to hit a 60Hz refresh? >> >> Another possibility would be some sort of display chip; >> does anyone know of one suitable for a slow 8-bit micro? > >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 still thinking that a counter clocking data out of RAM can make a VDI signal. |