jbb

New SDRAM board?

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Is this the board that is mentioned on the kickstarter than now has sdram instead?

Just got a couple of questions and wanted to make sure I was in the right place.

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Ok mostly I'm interested in this for the synth thing, but also to have a nice new fpga to play with!

Well I asked this on the kickstarter pages but I'll ask here in case anyone has any more information. I don't expect a quick or easy answer, just any information that anyone has at some point in a more appropriate place than a kickstarter page update.

How easy will it be to access the sdram? I realise that using the memory isn't trivial even with a controller, but while I might have been able to control SRAM it's a bit harder to control sdram.

My other question is, is it possible to use the usb port to send data to the fpga or is it only good for programming it? I see there is a schematic but it looks like eagle and I don't have that installed at the moment so thought I'd ask.

Anyway, it looks like an interesting board, just what I need which is why I backed the kickstart project for the synth and this :)

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I'm not familiar with the retrocade synth board, but...

When using SDRAM is quite tricky to get good performance, but getting average performance is relatively simple... I've been worked on a controller a while ago but have yet to find a use for it (http://hamsterworks.co.nz/mediawiki/index.php/SDRAM_Memory_Controller). Using an FPGA with an embedded Memory Controler Block is much easier and more reliable

It is common for the Papilio boards to have the RS232 TX and RX wired to the USB controller. If this board is the same you will be able to send up to 3Mb/sec.

See http://hamsterworks.co.nz/mediawiki/index.php/Module_16 and http://hamsterworks.co.nz/mediawiki/index.php/Module_17 for an example of doing host comms over RS232 on a different board.

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Thank you for that answer, it was what I was hoping for.

Ok, making a controller for sdram looks tricky but easy enough for me to understand it.

It's not as complicated as I thought.

And as your sample is in VHDL it gives me the excuse to learn it I've been looking for. (Only really used verilog until now).

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Hey jbb,

The new Papilio Plus board does indeed use the FT2232 chip like the rest of the boards. So there are two communication channels, one to program the FPGA and SPI, and another for uart comms up to 3Mb/s.

Jack.

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