8051 to DVI interface?
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From: nappy on 15 Feb 2007 19:32 "Paul Carpenter" <paul$@pcserviceselectronics.co.uk> wrote in message news:20070213.1006.325691snz(a)pcserviceselectronics.co.uk... > On Monday, in article > <7y7Ah.5884$o61.2906(a)newssvr19.news.prodigy.net> > spam(a)spam.com "nappy" wrote: > >>"Paul Carpenter" <paul$@pcserviceselectronics.co.uk> wrote in message >>news:20070212.1921.325648snz(a)pcserviceselectronics.co.uk... >>> >>> What type of DVI interface are you going to do >>> Analog >> >>What is an analog DVI interface? :) > > That would be 'funny' if you were right but you are wrong as analog DVI > interface for monitors exists. I suggest you read up on the matter as > that is refered to as DVI-A connections. Yes.. but those are not DVI connections.. that's just (analog) VGA piggybacked on the DVI connector. There is NO analog digital video interface.
From: nappy on 15 Feb 2007 21:32 "nappy" <spam(a)spam.com> wrote in message news:sY6Bh.10747$gj4.5626(a)newssvr14.news.prodigy.net... > > "Paul Carpenter" <paul$@pcserviceselectronics.co.uk> wrote in message > news:20070213.1006.325691snz(a)pcserviceselectronics.co.uk... >> On Monday, in article >> <7y7Ah.5884$o61.2906(a)newssvr19.news.prodigy.net> >> spam(a)spam.com "nappy" wrote: >> >>>"Paul Carpenter" <paul$@pcserviceselectronics.co.uk> wrote in message >>>news:20070212.1921.325648snz(a)pcserviceselectronics.co.uk... >>>> >>>> What type of DVI interface are you going to do >>>> Analog >>> >>>What is an analog DVI interface? :) >> >> That would be 'funny' if you were right but you are wrong as analog DVI >> interface for monitors exists. I suggest you read up on the matter as >> that is refered to as DVI-A connections. > > Yes.. but those are not DVI connections.. that's just (analog) VGA > piggybacked on the DVI connector. There is NO analog digital video > interface. FWIW I am a display developer. NTSC, VGA, DVI, 343, 170 etc... > >
From: Guy Macon on 16 Feb 2007 01:09 nappy wrote: >FWIW I am a display developer. NTSC, VGA, DVI, 343, 170 etc... Just the person I was looking for! In order to create a valid DVI signal that is: 1024 x 768 pixels 8 bits per color per pixel 60 Hz. refresh rate Generated from the data lines of a SRAM ....that said SRAM has it's address lines incremented by a counter (assume RD. WR. CS, etc are all taken care of properly). ....and that said counter can be reset to zero at any point you choose (not just powers of 2) .... What frequency should the counter run at? How many RAM addresses does it need to access? How many bits wide should the RAM be? At what number of bits should the counter be reset in order to start the next frame? Hint: A single DVI link consists of four twisted pairs (red, green, blue, and clock) to transmit 8 bits for each 3 colors per pixel. All you need to do is add them up and then figure out how much, if any time is spent blanking and retrcacing. This should be a simple task for a display developer. >There is NO analog digital video interface. In front of me is a catalog that lists the following connectors: DVI-A One set of eight pins and one set of four pins plush four contacts around the blade DVI-D Single Link Two sets of nine pins with no contacts around the blade DVI-D Dual Link One set of 24 pins with no contacts around the blade DVI-I Single Link Two sets of nine pins plus four contacts around the blade DVI-I Dual Link One set of 24 pins plus four contacts around the blade Tell me, what does the "A" in "DVI-A" stand for? Guy Macon <http://www.guymacon.com/>
From: Guy Macon on 16 Feb 2007 01:09 More info from my looking into this (I have the flu, so forgive me if this is disjointed and/or wrong...): http://www.playtool.com/pages/dvicompat/dvi.html gives these figures: 1024 X 768 @ 60 Hz = 65 MHz Pixel clock. http://www.interfacebus.com/Design_Connector_Digital_Visual_Interface_DVI_Bus.html Gives me the following DVI-D pinout: 1 TMDS Data2- 2 TMDS Data2+ 3 TMDS Data2/4 Shield 6 DDC Clock [SCL] 7 DDC Data [SDA] 8 Analog vertical sync 9 TMDS Data1- 10 TMDS Data1+ 11 TMDS Data1/3 Shield 14 +5 V Power 15 Ground 16 Hot Plug Detect 17 TMDS Data0- 18 TMDSData0+ 19 TMDS Data0/5 Shield 22 TMDS Clock Shield 23 TMDS Clock + 24 TMDS Clock - 4, 5, 12, 13, 20, 21 not used DDC = Display Data Channel TMDS.= Transition Minimized Differential Signal http://www.ddwg.org/lib/dvi_10.pdf (page 25 or so) talks about TMDS encoding. My next step is to get a good enough understanding of TMDS encoding to determine whether I can pre-encode before storing to SRAM or whether I need a post-SRAM hardware encoder. Or whether to give up and stick with VGA. Guy Macon <http://www.guymacon.com/>
From: Jim Granville on 16 Feb 2007 02:05
Guy Macon wrote: > nappy wrote: > > >>FWIW I am a display developer. NTSC, VGA, DVI, 343, 170 etc... > > > Just the person I was looking for! > > In order to create a valid DVI signal that is: > > 1024 x 768 pixels > > 8 bits per color per pixel > > 60 Hz. refresh rate > > Generated from the data lines of a SRAM > > ...that said SRAM has it's address lines incremented by > a counter (assume RD. WR. CS, etc are all taken care of > properly). > > ...and that said counter can be reset to zero at any > point you choose (not just powers of 2) > > > ... > > > > What frequency should the counter run at? > > How many RAM addresses does it need to access? > > How many bits wide should the RAM be? > > At what number of bits should the counter be reset > in order to start the next frame? > > Hint: A single DVI link consists of four twisted pairs > (red, green, blue, and clock) to transmit 8 bits for > each 3 colors per pixel. All you need to do is add them up > and then figure out how much, if any time is spent blanking > and retrcacing. This should be a simple task for a display > developer. You can get some easy ball-park numbers : - assume no dead-time, and you get 60*768*1024 = ~47MHz (call that 50MHz). Ram width is up to you - 24bits wide = Pixel clock, 8 bits = 3x pixel clock. Plus you need to serialise if this is LVDS, so to serialise 8 bits digital onto 1 pair, is > 8x pixel clock = 2.5ns data slices So to keep this sensible, you'd probably need x24 SRAM, and commercial SerDes encoder. Check a recent device like http://www.fairchildsemi.com/ds/FI/FIN324C.pdf targets links to LCDs in cellphones, (Wider fanin, but lower Fin than above numbers), has link clock of ~275MHz -jg |