markbuckingham

External SRAM?

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It's definitely possible. There was a prototype cpld+sram chip wing (C/RAM wing), but I think it was never put in production.

The new Papilio Plus has a built-in SRAM chip.

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So has anyone messed around with adding some form of volitile memory to the Papilio One?

I need about 200Kbytes, to store images.  And need to be able to read it at 2Mbytes/s minimum.

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It's definitely possible. There was a prototype cpld+sram chip wing (C/RAM wing), but I think it was never put in production.

The new Papilio Plus has a built-in SRAM chip.

 

Unless another version showed up when I wasn't looking, it's Papilio Pro, and DRAM, not SRAM.

 

I'd been intending to wire up a DRAM chip to my Papilio One, but parallel data/address busses are a pain to wire up by hand. I was going to do a board, but now I have a Papilio Pro.

 

 

 

So has anyone messed around with adding some form of volitile memory to the Papilio One?

I need about 200Kbytes, to store images.  And need to be able to read it at 2Mbytes/s minimum.

 

If you just need memory, easiest might probably be a SPI dataflash, just due to the number of address/data lines to hook up in the alternatives. That's not volatile, but while they exist, serial SRAMs are scarce and relatively expensive, and I didn't find any that large in a quick search (largest I saw was 1 Mbit, 128 KB). If you're worried about wear (and note that some are rated for 100000+ cycles), just get a huge one and spread your writes out.

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So has anyone messed around with adding some form of volitile memory to the Papilio One?

I need about 200Kbytes, to store images.  And need to be able to read it at 2Mbytes/s minimum.

 

Donziboy, the Papilio has SPI flash that you can load images into and here is a good writeup about a bootloader that will copy data from SPI Flash into SRAM at boot. The Papilio Pro has SDRAM instead of SRAM so it will be harder to accomplish the same thing but is possible.

 

Another approach is to look at the ZPUino Soft Processor which has a library called smallFS. It will let you place your images in a directory where your Arduino sketch lives and will take care of loading the images from SPI Flash for you. You can then display the image using the ZPUino VGA adapter or, if you have a Papilio Pro, you can use malloc to place the images into SDRAM. The ZPUino implements a rock solid SDRAM controller so you don't have to deal with trying to get SDRAM to work in VHDL.

 

The other option is to use an SD Card and copy from SDCard to SDRAM on the Papilio Pro.

 

Please take a look at this forum thread for a concrete example of how you would use smallFS to load an image to the VGAZX adapter using the ZPUino:

http://forum.gadgetfactory.net/index.php?/topic/1550-building-complete-papilio-soc-for-logicstart-megawing/

 

Jack.

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Im currently working out the details to make a Mk2 version of this.  It had alot of limitations so I am shooting a little higher this time.  My current plan is to use 4 TLC5940's multiplexed to 64 RGB led's.  A single image, that is 64 x 200 will take up 57.6Kbytes (595 version only needs 4800Bytes).  I would like to do animations and effects on most likely a Teensy 3 and then send the information to some storage for the Papilio to pull as it needs it.

 

It may end up a pipe dream but if I dont try I wont succeed.

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