jbb

Got mine

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Mine just arrived in the post this morning, excited to see what I can do with it. It took 13 days from ordering it at seeed to delivery in the UK which was far faster than I'd expected.

I would like to use it to generate some graphics, I think my first project will of course be to flash some LEDs to make sure everything works, then I want to get VGA output working. I'll want to get the RAM working for that too. I've done VGA on other devices so I'm confident I can make that work but RAM is new to me, so that should be fun. I'm more interested in verilog than embedded CPUs although I might try that out too :)

I'd like to make it generate HDMI after reading other posts eventually. Am I right to understand that it can be directly connected to an HDMI lead, subject obviously to correct configuration and design? The signal levels etc are correct for it? Going to be a while before I'm up to doing that anyway.

Thanks for this anyway, gives me something fun to play with and learn over christmas :)

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Yes, it should be possible to just cut the end off an HDMI cable and connect it to the Papilio pins. There is a Xilinx App note where they did so in their initial testing with HDMI.

Here are two projects that do HDMI on the Papilio:

http://forum.gadgetf...put-on-fpga-r21

http://forum.gadgetf...apilio-plus-r61

Here is the Xilinx App note:

http://www.xilinx.com/support/documentation/application_notes/xapp495_S6TMDS_Video_Interface.pdf

Jack.

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Thank you for the information.

It's going to be a while before I feel ready to tackle HDMI but it's good to have some reading. SO much to learn :)

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Well I got a simple VGA 1 bit per color adapter working, next step is I want to get it to display from SDRAM rather than just low resolution block memory. I'm thinking first I should get it working with block memory with artificially introduced latency as I'll have a few clock cycles latency on any SDRAM controller, does that make sense.

My real next question is about SDRAM memory controllers. Do we have anything we can just drop in? I looked at the hamsterworks posts which were very helpful but not quite a drop in component. I can work on my own, it's a little out of my comfort zone as I'm a c++ developer and new to this, but I figure it's not beyond me to make one. Am I right in thinking that you need to ensure you do refresh cycles frequently enough but apart from that the speed isn;t that important as I think it would be nice to start slow so I can look at outputs on my oscilloscope if necessary...

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jbb,

Here are the SDRAM options so far (http://retrocade.gadgetfactory.net/index.php?n=Main.PapilioPro#PProSdram). Probably the closest to drop in ready is Alvie's SDRAM controller. I also was looking at the Xula's Open Source SDRAM controller at one point but never finished getting it to work with the Papilio.

Might be easiest to start with the 64KB of internal BRAM and then see what kind of SDRAM controller are posted.

Jack.

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First of all Merry Christmas to everyone here :)

Secondly I've been looking into using the sdram for video. I have a question though. With a fairly low video resolution of 640x480 there is a pixel clock of 25MHz or so. If I need 3 bytes per pixel for RGB then that's 75MB per second needed. But looking at the memory it can only return one every 10ns but that's if you manage to read a byte every clock cycle at 100MHZ which isn't really possible and if you manage one every 2 clocks then it's only 50MB/s which isn't enough even for this lowish resolution.

Am I missing something?

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