Post by thread:[EE] Cheapest way to drive 4 SVGA monitors

I'm considering a project which involves displaying essentially static content on 4 15" LCDs. Essentially static being defined as "If it can be done cheaper at the expense of update rate, then let's make it cheaper." I'm thinking updating maybe once per minute. I'd like to keep the hardware as cheap as possible. I don't need to do anything fancy, but one thing I do want to avoid is seeing the screen slowly update - even though it's only updating once a minute or so, I want the update to happen instantly. The data for a new image could come over USB, or a memory card, or whatever's convenient. I can always create a data path later, the thing I'm working on now is the actual driving of four displays. So the best I've come up with is using a cheap FPGA and some reasonably fast SDRAM with enough space to hold two images - one buffer, and one active. This would be around 18MB for 4 displays of 1024x768x24bit imagery. Unfortunately this runs to 540Mbytes/second of memory throughput not counting updating the memory (1024x768 pixels * 3bytes * 4 screens). And from there the cost just goes up since I can't easily use an off the shelf fpga board for this since the memory requirements are so interesting. I could get 4 separate FPGA boards, though. I suppose a high end FPGA board with DDR ram would do it, but cost is high. I'd prefer not having 4 PCs running, but have considered getting a cheap computer with several VGA adaptors and windows XP. Would be nice if it were smaller with lower power requirements though. Might be the cheapest option, and certainly the easiest/quickest to develop for. So... Suggestions? Any FPGA boards I should look at? Alternative methods? -Adam -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ Interested in electronics? Check out the projects at http://ubasics.com Building your own house? Check out http://ubasics.com/home/

On Fri, 2008-01-04 at 10:08 -0500, M. Adam Davis wrote: > I'd prefer not having 4 PCs running, but have considered getting a > cheap computer with several VGA adaptors and windows XP. Would be > nice if it were smaller with lower power requirements though. Might > be the cheapest option, and certainly the easiest/quickest to develop > for. > > So... Suggestions? Any FPGA boards I should look at? Alternative methods? I would certainly be interested in the FPGA solution, it would be lowest power by far, but if you're not going to make your own board, the PC idea will be much cheaper. Two dual head video cards are all you need, from that point it's just a matter of software. I don't know what your budget is. If low power is of upmost concern then an older laptop with some USB-VGA adapters may fit the bill. TTYL

On Fri, 4 Jan 2008 10:08:38 -0500, you wrote: {Quote hidden}>I'm considering a project which involves displaying essentially static >content on 4 15" LCDs. Essentially static being defined as "If it can >be done cheaper at the expense of update rate, then let's make it >cheaper." I'm thinking updating maybe once per minute. > >I'd like to keep the hardware as cheap as possible. I don't need to >do anything fancy, but one thing I do want to avoid is seeing the >screen slowly update - even though it's only updating once a minute or >so, I want the update to happen instantly. The data for a new image >could come over USB, or a memory card, or whatever's convenient. I >can always create a data path later, the thing I'm working on now is >the actual driving of four displays. > >So the best I've come up with is using a cheap FPGA and some >reasonably fast SDRAM with enough space to hold two images - one >buffer, and one active. This would be around 18MB for 4 displays of >1024x768x24bit imagery. Unfortunately this runs to 540Mbytes/second >of memory throughput not counting updating the memory (1024x768 pixels >* 3bytes * 4 screens). > >And from there the cost just goes up since I can't easily use an off >the shelf fpga board for this since the memory requirements are so >interesting. I could get 4 separate FPGA boards, though. I suppose a >high end FPGA board with DDR ram would do it, but cost is high. > >I'd prefer not having 4 PCs running, but have considered getting a >cheap computer with several VGA adaptors and windows XP. Would be >nice if it were smaller with lower power requirements though. Might >be the cheapest option, and certainly the easiest/quickest to develop >for. > >So... Suggestions? Any FPGA boards I should look at? Alternative methods? Do a web search for 'digital signage'. There are some cheap media player type devices that will display stuff from memory cards - the only question is whether you can get sufficient control. They are likely to be cheap enough to use one per monitor.

$350 ready made kit, using an FPGA However a $20, 100MHz old desktop PC would be cheaper. You didn't say if there is the same information on those four LCD or it's different... On 1/4/08, M. Adam Davis <spam_OUTstienmanTakeThisOuTgmail.com> wrote: {Quote hidden}> I'm considering a project which involves displaying essentially static > content on 4 15" LCDs. Essentially static being defined as "If it can > be done cheaper at the expense of update rate, then let's make it > cheaper." I'm thinking updating maybe once per minute. > > I'd like to keep the hardware as cheap as possible. I don't need to > do anything fancy, but one thing I do want to avoid is seeing the > screen slowly update - even though it's only updating once a minute or > so, I want the update to happen instantly. The data for a new image > could come over USB, or a memory card, or whatever's convenient. I > can always create a data path later, the thing I'm working on now is > the actual driving of four displays. > > So the best I've come up with is using a cheap FPGA and some > reasonably fast SDRAM with enough space to hold two images - one > buffer, and one active. This would be around 18MB for 4 displays of > 1024x768x24bit imagery. Unfortunately this runs to 540Mbytes/second > of memory throughput not counting updating the memory (1024x768 pixels > * 3bytes * 4 screens). > > And from there the cost just goes up since I can't easily use an off > the shelf fpga board for this since the memory requirements are so > interesting. I could get 4 separate FPGA boards, though. I suppose a > high end FPGA board with DDR ram would do it, but cost is high. > > I'd prefer not having 4 PCs running, but have considered getting a > cheap computer with several VGA adaptors and windows XP. Would be > nice if it were smaller with lower power requirements though. Might > be the cheapest option, and certainly the easiest/quickest to develop > for. > > So... Suggestions? Any FPGA boards I should look at? Alternative methods? > > -Adam > > -- > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > - - - - - - - - - - - - - - - - - - - - - - - - - > Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ > > Interested in electronics? Check out the projects at http://ubasics.com > > Building your own house? Check out http://ubasics.com/home/ > -

Is there a $350 ready made FPGA kit for this? Or a $350 FPGA kit that needs a few video dacs or R2R ladders or etc (minor stuff) to do this? The displays need to be able to display separate info - otherwise a $50 FPGA kit could do it with a video amplifier/splitter circuit. However, they need to be synchronized (think video wall type app) so separate controllers would need to be sync-able to some degree. If I could get a very cheap, very small, very low power solution that couldn't synchronize better than within one second then I'd consider it simply due to the other factors. Shouldn't be too great an issue, but does limit some choices. I did poke around a bit. Looks like an FPGA with 16 bit wide DDR2 200MHz memory (800MBytes/second) could manage the throughput. Add some video DACs... -Adam On 1/4/08, Vasile Surducan <.....piclist9KILLspam@spam@gmail.com> wrote: {Quote hidden}> $350 ready made kit, using an FPGA > However a $20, 100MHz old desktop PC would be cheaper. > You didn't say if there is the same information on those four LCD or > it's different... > > On 1/4/08, M. Adam Davis <stienmanKILLspamgmail.com> wrote: > > I'm considering a project which involves displaying essentially static > > content on 4 15" LCDs. Essentially static being defined as "If it can > > be done cheaper at the expense of update rate, then let's make it > > cheaper." I'm thinking updating maybe once per minute. > > > > I'd like to keep the hardware as cheap as possible. I don't need to > > do anything fancy, but one thing I do want to avoid is seeing the > > screen slowly update - even though it's only updating once a minute or > > so, I want the update to happen instantly. The data for a new image > > could come over USB, or a memory card, or whatever's convenient. I > > can always create a data path later, the thing I'm working on now is > > the actual driving of four displays. > > > > So the best I've come up with is using a cheap FPGA and some > > reasonably fast SDRAM with enough space to hold two images - one > > buffer, and one active. This would be around 18MB for 4 displays of > > 1024x768x24bit imagery. Unfortunately this runs to 540Mbytes/second > > of memory throughput not counting updating the memory (1024x768 pixels > > * 3bytes * 4 screens). > > > > And from there the cost just goes up since I can't easily use an off > > the shelf fpga board for this since the memory requirements are so > > interesting. I could get 4 separate FPGA boards, though. I suppose a > > high end FPGA board with DDR ram would do it, but cost is high. > > > > I'd prefer not having 4 PCs running, but have considered getting a > > cheap computer with several VGA adaptors and windows XP. Would be > > nice if it were smaller with lower power requirements though. Might > > be the cheapest option, and certainly the easiest/quickest to develop > > for. > > > > So... Suggestions? Any FPGA boards I should look at? Alternative methods? > > > > -Adam > > > > -- > > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > > - - - - - - - - - - - - - - - - - - - - - - - - - > > Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ > > > > Interested in electronics? Check out the projects at http://ubasics.com > > > > Building your own house? Check out http://ubasics.com/home/ > > --

There's a different approach - using PCI cards. I always shied away from them due to the bus complexity, but thinking back to my school days I do recall going over it and thinking that it's not nearly as complex as I had expected. Still more than ISA... Adds size, but may be simpler, and possibly cheaper if I can creatively source some PCI cards... -Adam On 1/4/08, Dario Greggio <.....adpm.toKILLspam.....inwind.it> wrote: {Quote hidden}> M. Adam Davis wrote: > > > I'm considering a project which involves displaying essentially static > > content on 4 15" LCDs. Essentially static being defined as "If it can > > be done cheaper at the expense of update rate, then let's make it > > cheaper." I'm thinking updating maybe once per minute. > > Welcome to the club :) > http://forum.microchip.com/tm.aspx?m=288313 > > Yeah, sure the FPGA way is the right one, but needs some development. > > I'll be interested in how you proceed on that. > > -- > Ciao, Dario > -

Is this a one-off, a fun hobby project, or a commercial venture? If it's a one-off, here's something not quite the same but similar: digital photo picture frame: www.newegg.com/Product/Product.aspx?Item=N82E16882597005 brochure here: http://www.viewsonic.com/pdf/us_eng/products/DF88W-523_Dec_2007a.pdf USB connection and price around US$150... M. Adam Davis wrote: {Quote hidden}> Is there a $350 ready made FPGA kit for this? Or a $350 FPGA kit that > needs a few video dacs or R2R ladders or etc (minor stuff) to do this? > > The displays need to be able to display separate info - otherwise a > $50 FPGA kit could do it with a video amplifier/splitter circuit. > However, they need to be synchronized (think video wall type app) so > separate controllers would need to be sync-able to some degree. If I > could get a very cheap, very small, very low power solution that > couldn't synchronize better than within one second then I'd consider > it simply due to the other factors. Shouldn't be too great an issue, > but does limit some choices. > > I did poke around a bit. Looks like an FPGA with 16 bit wide DDR2 > 200MHz memory (800MBytes/second) could manage the throughput. Add > some video DACs... > > -Adam

So are you talking text or graphics? Text..there is a company that has a serial to VGA interface (have it somewhere) and it works pretty good. Just a TTL serial for commands to where you place the data (x/y offsets essentially) and then send the text to display. You can update just pieces of it as well. If graphics....different story. SVGA is what...1024 pixels x 768 lines, non-interlaced. So your doing 8 bit graphics, thats 24 bits per pixel (RGB), times 1024 time 768. Thats just for one frame of what needs to be displayed. Since you want a seemless update, you will need two video buffers. Probably the easiest is to use VRAM (whoa...do they still make that?) or SDRAM, (i think it was SDRAM?) where you have a buffer that you dump a 'line' of data out and then you can serially stream it out. Worked great on a video card I did years ago. So you have two sets of these, and you will have to constantly stream out one buffer else the video of course will just fade away. The syncs are pretty easy, can just do a FPGA state machine for that....pre-sync, sync and post sync then the video for each line and then the vsync pulse including the blank lines for settle at the top. Oh..this is all from driving CRT's but the LCD analog interface has to be the same. For digiital video, its a different story but its similiar. The video from each line if designed right, would be a stream of red, green and blue pixel data and that would then be driven directly into a triple 8 bit video DAC, and followed by a video driver. The syncs can just be driven out using a line driver device. Updating the frame memory is simply setting the RGB values for each pixel. Think of your memory as mapped to the display and it makes more sense as you address for this. You didnt mention the 'source' for the data, so that will have to be considered. Since you only need to update once a minute or so, that gives you plenty of time to stream in the new data. Sounds like a fun project. A challenge, but fun. "M. Adam Davis" <EraseMEstienmanspam_OUTTakeThisOuTgmail.com> wrote: I'm considering a project which involves displaying essentially static content on 4 15" LCDs. Essentially static being defined as "If it can be done cheaper at the expense of update rate, then let's make it cheaper." I'm thinking updating maybe once per minute. I'd like to keep the hardware as cheap as possible. I don't need to do anything fancy, but one thing I do want to avoid is seeing the screen slowly update - even though it's only updating once a minute or so, I want the update to happen instantly. The data for a new image could come over USB, or a memory card, or whatever's convenient. I can always create a data path later, the thing I'm working on now is the actual driving of four displays. So the best I've come up with is using a cheap FPGA and some reasonably fast SDRAM with enough space to hold two images - one buffer, and one active. This would be around 18MB for 4 displays of 1024x768x24bit imagery. Unfortunately this runs to 540Mbytes/second of memory throughput not counting updating the memory (1024x768 pixels * 3bytes * 4 screens). And from there the cost just goes up since I can't easily use an off the shelf fpga board for this since the memory requirements are so interesting. I could get 4 separate FPGA boards, though. I suppose a high end FPGA board with DDR ram would do it, but cost is high. I'd prefer not having 4 PCs running, but have considered getting a cheap computer with several VGA adaptors and windows XP. Would be nice if it were smaller with lower power requirements though. Might be the cheapest option, and certainly the easiest/quickest to develop for. So... Suggestions? Any FPGA boards I should look at? Alternative methods? -Adam -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ Interested in electronics? Check out the projects at http://ubasics.com Building your own house? Check out http://ubasics.com/home/

On 1/4/08, M. Adam Davis <stienmanspam_OUTgmail.com> wrote: > Is there a $350 ready made FPGA kit for this? Actually $400: http://www.altera.com/products/devkits/altera/kit-cyc3-embedded.html Or a $350 FPGA kit that {Quote hidden}> needs a few video dacs or R2R ladders or etc (minor stuff) to do this? > > The displays need to be able to display separate info - otherwise a > $50 FPGA kit could do it with a video amplifier/splitter circuit. > However, they need to be synchronized (think video wall type app) so > separate controllers would need to be sync-able to some degree. If I > could get a very cheap, very small, very low power solution that > couldn't synchronize better than within one second then I'd consider > it simply due to the other factors. Shouldn't be too great an issue, > but does limit some choices. > > I did poke around a bit. Looks like an FPGA with 16 bit wide DDR2 > 200MHz memory (800MBytes/second) could manage the throughput. Add > some video DACs... > > -Adam > > On 1/4/08, Vasile Surducan <@spam@piclist9KILLspamgmail.com> wrote: > > $350 ready made kit, using an FPGA > > However a $20, 100MHz old desktop PC would be cheaper. > > You didn't say if there is the same information on those four LCD or > > it's different... > > > > On 1/4/08, M. Adam Davis <KILLspamstienmanKILLspamgmail.com> wrote: > > > I'm considering a project which involves displaying essentially static > > > content on 4 15" LCDs. Essentially static being defined as "If it can > > > be done cheaper at the expense of update rate, then let's make it > > > cheaper." I'm thinking updating maybe once per minute. > > > > > > I'd like to keep the hardware as cheap as possible. I don't need to > > > do anything fancy, but one thing I do want to avoid is seeing the > > > screen slowly update - even though it's only updating once a minute or > > > so, I want the update to happen instantly. The data for a new image > > > could come over USB, or a memory card, or whatever's convenient. I > > > can always create a data path later, the thing I'm working on now is > > > the actual driving of four displays. > > > > > > So the best I've come up with is using a cheap FPGA and some > > > reasonably fast SDRAM with enough space to hold two images - one > > > buffer, and one active. This would be around 18MB for 4 displays of > > > 1024x768x24bit imagery. Unfortunately this runs to 540Mbytes/second > > > of memory throughput not counting updating the memory (1024x768 pixels > > > * 3bytes * 4 screens). > > > > > > And from there the cost just goes up since I can't easily use an off > > > the shelf fpga board for this since the memory requirements are so > > > interesting. I could get 4 separate FPGA boards, though. I suppose a > > > high end FPGA board with DDR ram would do it, but cost is high. > > > > > > I'd prefer not having 4 PCs running, but have considered getting a > > > cheap computer with several VGA adaptors and windows XP. Would be > > > nice if it were smaller with lower power requirements though. Might > > > be the cheapest option, and certainly the easiest/quickest to develop > > > for. > > > > > > So... Suggestions? Any FPGA boards I should look at? Alternative methods? > > > > > > -Adam > > > > > > -- > > > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > > > - - - - - - - - - - - - - - - - - - - - - - - - - > > > Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ > > > > > > Interested in electronics? Check out the projects at http://ubasics.com > > > > > > Building your own house? Check out http://ubasics.com/home/ > > > -- >

On 1/4/08, M. Adam Davis <RemoveMEstienmanTakeThisOuTgmail.com> wrote: > Is there a $350 ready made FPGA kit for this? Actually $400: http://www.altera.com/products/devkits/altera/kit-cyc3-embedded.html Or a $350 FPGA kit that {Quote hidden}> needs a few video dacs or R2R ladders or etc (minor stuff) to do this? > > The displays need to be able to display separate info - otherwise a > $50 FPGA kit could do it with a video amplifier/splitter circuit. > However, they need to be synchronized (think video wall type app) so > separate controllers would need to be sync-able to some degree. If I > could get a very cheap, very small, very low power solution that > couldn't synchronize better than within one second then I'd consider > it simply due to the other factors. Shouldn't be too great an issue, > but does limit some choices. > > I did poke around a bit. Looks like an FPGA with 16 bit wide DDR2 > 200MHz memory (800MBytes/second) could manage the throughput. Add > some video DACs... > > -Adam > > On 1/4/08, Vasile Surducan <spamBeGonepiclist9spamBeGonegmail.com> wrote: > > $350 ready made kit, using an FPGA > > However a $20, 100MHz old desktop PC would be cheaper. > > You didn't say if there is the same information on those four LCD or > > it's different... > > > > On 1/4/08, M. Adam Davis <TakeThisOuTstienmanEraseMEspam_OUTgmail.com> wrote: > > > I'm considering a project which involves displaying essentially static > > > content on 4 15" LCDs. Essentially static being defined as "If it can > > > be done cheaper at the expense of update rate, then let's make it > > > cheaper." I'm thinking updating maybe once per minute. > > > > > > I'd like to keep the hardware as cheap as possible. I don't need to > > > do anything fancy, but one thing I do want to avoid is seeing the > > > screen slowly update - even though it's only updating once a minute or > > > so, I want the update to happen instantly. The data for a new image > > > could come over USB, or a memory card, or whatever's convenient. I > > > can always create a data path later, the thing I'm working on now is > > > the actual driving of four displays. > > > > > > So the best I've come up with is using a cheap FPGA and some > > > reasonably fast SDRAM with enough space to hold two images - one > > > buffer, and one active. This would be around 18MB for 4 displays of > > > 1024x768x24bit imagery. Unfortunately this runs to 540Mbytes/second > > > of memory throughput not counting updating the memory (1024x768 pixels > > > * 3bytes * 4 screens). > > > > > > And from there the cost just goes up since I can't easily use an off > > > the shelf fpga board for this since the memory requirements are so > > > interesting. I could get 4 separate FPGA boards, though. I suppose a > > > high end FPGA board with DDR ram would do it, but cost is high. > > > > > > I'd prefer not having 4 PCs running, but have considered getting a > > > cheap computer with several VGA adaptors and windows XP. Would be > > > nice if it were smaller with lower power requirements though. Might > > > be the cheapest option, and certainly the easiest/quickest to develop > > > for. > > > > > > So... Suggestions? Any FPGA boards I should look at? Alternative methods? > > > > > > -Adam > > > > > > -- > > > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > > > - - - - - - - - - - - - - - - - - - - - - - - - - > > > Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ > > > > > > Interested in electronics? Check out the projects at http://ubasics.com > > > > > > Building your own house? Check out http://ubasics.com/home/ > > > -- >

Well I want it all, but cost is the driving factor. If I can't afford it, I'm not going to do it. If I can afford it, but it's large, noisy, and power hungry I probably will. Complexity is an issue in that I don't want to spend any time doing maintenance, and I want to spend as little time as possible building it unless it yields benefits in either a marketable product, or tangible learning opportunities. If possible I'd like to come out on the other end with a marketable product, which means that the unit needs to cost less than ~$50 [USD] in parts and labor (which I believe is possible given my current optimism) for a memory card or USB version (monitors not included). So while I'm looking at a lot of options, I'm focusing on building one for personal use, and building a prototype using dev boards for proof of concept as a product. So the PC idea is fine, but it pretty much throws out possible production. Same with using the PCI cards. -Adam On Jan 4, 2008 4:56 PM, alan smith <micro_eng2EraseME.....yahoo.com> wrote: {Quote hidden}> you want it simple....is cost an issue then? Within reason ? > > > peter green <EraseMEplugwashp10link.net> wrote: > > I'd prefer not having 4 PCs running, but have considered getting a > > cheap computer with several VGA adaptors and windows XP. Would be > > nice if it were smaller with lower power requirements though. > How about using say a VIA epia based system? stick in a dualhead PCI > graphics card and then use a USB adaptor or something for the fourth > monitor. > > > -

On 1/4/08, M. Adam Davis <RemoveMEstienmanspam_OUTKILLspamgmail.com> wrote: > Well I want it all, but cost is the driving factor. If I can't afford > it, I'm not going to do it. If I can afford it, but it's large, > noisy, and power hungry I probably will. Complexity is an issue in > that I don't want to spend any time doing maintenance, and I want to > spend as little time as possible building it unless it yields benefits > in either a marketable product, or tangible learning opportunities. > > If possible I'd like to come out on the other end with a marketable > product, which means that the unit needs to cost less than ~$50 [USD] > in parts and labor I believed you are an old boy. It seems not. :) (which I believe is possible given my current {Quote hidden}> optimism) for a memory card or USB version (monitors not included). > > So while I'm looking at a lot of options, I'm focusing on building one > for personal use, and building a prototype using dev boards for proof > of concept as a product. So the PC idea is fine, but it pretty much > throws out possible production. Same with using the PCI cards. > > -Adam > > On Jan 4, 2008 4:56 PM, alan smith <RemoveMEmicro_eng2TakeThisOuTspamyahoo.com> wrote: > > you want it simple....is cost an issue then? Within reason ? > > > > > > peter green <EraseMEplugwashspamspamBeGonep10link.net> wrote: > > > I'd prefer not having 4 PCs running, but have considered getting a > > > cheap computer with several VGA adaptors and windows XP. Would be > > > nice if it were smaller with lower power requirements though. > > How about using say a VIA epia based system? stick in a dualhead PCI > > graphics card and then use a USB adaptor or something for the fourth > > monitor. > > > > > > --

I have one that I haven't played with yet - got to meet Chip at last spring's ESC. It's fast enough to drive several VGA monitors, as well as do color composite video, but the internal memory is small so I would have to look at using external memory. Still, it would probably work well, and should be fairly inexpensive. Digikey has 4Mx16 (64Mbit) 133MHz SDRAM in TSOP for $2.66 in quantities of one. I could use one for each monitor to meet bandwidth requirements if I'm happy with 16 bits of color. They are fast enough to give me 32 bits per pixel or drive two monitors as well (each monitor needs 47M+ pixels per second). They are 3.3V devices, and standard SDRAM, so I imagine the propeller can handle them, though I'd probably want to look at having a shared data bus so the pixel data goes from memory to the DACs, rather than through the propeller. Although I just unearthed another PC and a 2 output PCI card, so I might just go the easy route... -Adam On Jan 5, 2008 10:26 AM, Dave Lagzdin <dtekk.comSTOPspamspam_OUTgmail.com> wrote: {Quote hidden}> On 04/01/2008, M. Adam Davis <spamBeGonestienmanSTOPspamEraseMEgmail.com> wrote: > > > > I'm considering a project which involves displaying essentially static > > content on 4 15" LCDs. Essentially static being defined as "If it can > > be done cheaper at the expense of update rate, then let's make it > > cheaper." I'm thinking updating maybe once per minute. > > > > I > > So... Suggestions? Any FPGA boards I should look at? Alternative > > methods? > > > > -Adam > > > > - > > What about the "Propeller" ? They claim it does multiple video feeds > --

Hey, Do your monitors have a digital or analog input? If analog, prepare to get a proper A/D converter. I've used the onboard on an Altera DE1 kit (R-2R network) and it's too slow to drive the horizontal speed of 640*480 at 60hz. Driving 4 times 1024*768 at 60 hz would eat up about 750MB/s of bandwidth in your memory. You would be best off with a 32-bit or 64-bit interface, fighting for the last few Hz is not fun. Using an FPGA you would be able to get very far. DVI driving should be well possible without any converter but with a bit more onboard logic. You wouldn't need a big FPGA to do the driving, I think an 8k unit from Altera or an equivalent one from another company (Xilinx, Actel, Lattice etc.) would be sufficient in terms of connections. For development, a DE1 like the one I have, or even a simpler board would be sufficient, but do watch out that you get one with a 32/64 bit memory interface (DE1 is 2x 16bit and slightly insufficient memory). If it's just for you, make it with an old PC and four identical PCI video cards. If it's not just for you, try the FPGA route for a lot of learning. Regards, Peter