Set output frequency ( 24, 48, 50, 60, 72 Hz for exemple )
Set write adr in video memory
Fill with RGB value the whole memory
Set data mode : 8b / 24b
Swap buffers
8b or 24b data bus
Write/Read byte or RGB value (24b) in module’s video memory
The module works with swapping buffers : it’s displaying FrontBuffer while user write in BackBuffer, then user send Swap command and on the next frame the module swap buffers, so the user can write the next frame in memory without tearing …ect…
The module send on DVI-D/HDMI the video memory as 24b RGB …
HDCP is useless IMO …
Isn’t this a good idea ?!
This kind of module can be used to use HD-TV as display for embeded product … great !
The goal isn’t really to display vidéo, but more to use Home’s TV as Domotic control panel …
Uh, have you done the math on this? You will find that the data rate is very high. Lets consider 640x480. for 24 bit RGB values and a 30 hz update rate, that is a bit under 28 MB/Sec.
You’ll need a big fat pipe to the video memory to make it happen and you’ll need a fair amount of power on both ends of the pipe. PCI express makes the most sense and there are display cards that support that but you are well along to way to building a PC.
A suggestion, just get the cheapest miniITX motherboard you can find with DVI on it. Jetway makes a decent one.
The parts requirements for this project aren’t that big - cheap FPGA, a single SDRAM chip for the framebuffer (don’t need a whole SIMM/DIMM), TFP410 encoder, configuration flash, connectors, regulators.
But using a UART interface to update a framebuffer directly? forget it. If your output is 640x480 at 24bpp, It’ll take you 80 seconds to draw a single frame at a 115200bps baud rate, assuming no compression or draw acceleration. 1920x1080 @ 24bpp is 9 minutes. Based on that alone, I’d go with an actual computer.
Mind you, a FPGA development board with a video output is an interesting project. Throw on an audio output, a few connectors for hooking up game controllers, a flash or SD card interface for storing games and you could build yourself a 100% accurate Atari or NES emulator. Though I’m sure I’m not the first person to come up with a “FPGA-gamestation” idea, so this might be out there already…
I’ve been thinking about designing something like this for a while; essentially the same design that gmarsh / denial have proposed. If I were to design / build it / sell it, what would be a price point that people would be willing to pay?
