Thomas Hornschuh

Papilio Pro still produced?

8 posts in this topic

Hi,

I have seen the pro is out of stock, and also can't be preordered. Will it be in produced again or is the product retired?

Regards

Thomas

 

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It's not retired but the SDRAM chip that is used is obsolete. We are looking for replacements which will take a little time...

Jack.

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Are there still SDR-SDRAMs on the market?  DDR will be difficult with a soft memory controller, and SRAM is small and expensive...

I'm currently working on a project which implements th RISC-V ISA (see riscv.org) and runs a port of eLua  to this architecture on a Papilio Pro.

It is making great progress, I will post more information here in the forum in the next days. 

I'm already thinking about moving to another board (e.g. Pipistrello, Arty). But in some way I like the PaPro a lot:

  • It is "publishing friendly" because I don't need a Xilinx CoreGen generated core to access the DRAM.
  • With ISE a synthesis run for the LX9 usually takes only a few minutes including map, place and route, so it is possible to quick check design changes in Hardware

As long a design fits in the LX9 it is really a convenient platform. And Xilinx has recently announced that they continue supporting the Spartan 6 series because of their success.

Thomas

 

 

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Hello Thomas,

Yes, it will continue with SDRAM, we have identified an ISSI SDRAM chip to use instead but there is still some work to be done to verify before we do the next run of boards. I'm also seeing if I can find a supply of the current SDRAM chips to do one more run of the Papilio Pro with the current chip.

Jack.

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On 20/3/2017 at 1:49 PM, Jack Gassett said:

Hello Thomas,

Yes, it will continue with SDRAM, we have identified an ISSI SDRAM chip to use instead but there is still some work to be done to verify before we do the next run of boards. I'm also seeing if I can find a supply of the current SDRAM chips to do one more run of the Papilio Pro with the current chip.

Jack.

So, where can I buy it now? 

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I wonder how many users of this board are frightened or put off using the SDRAM due to the complexity? I am! I have read the datasheet, and I was surprised that this device is a lot more complicated than an old fashioned 64kbit DRAM which at least only needed the refresh.

I was tempted by the Duo, mainly because of the use of the Static RAM, but the cost in the UK (from SKPang) has risen enough to put me off. I will be in the US in May, so perhaps I could order one and have it delivered to the hotel???

For my current project (which is stalled somewhat) I am using all the I/O for DAC and ADC connections, leaving no spare pins to wire up a simple DIL SRAM, or even the VGA adapter.

I guess I was wondering how many people bought the Pro and then didn't ever use the SDRAM. Given that you possible have to re-work the board to take a different SDRAM, could you make connections for SDRAM on the top layer and SRAM on the bottom layer, allowing you to offer a Pro+ with either SDRAM mounted or SRAM mounted. Just wondering...

Anyway Jack, thanks for a great product.

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Hi Papry, I can‘t speak for others, but at the end the DRAM is not that complicated, given that you don’t need to write all the code from scratch, there exist several implementations, one is the Hamsterworks controller.

The latest version on his website unfortunately had a small issue which prevents running it out of the box. 

Here https://github.com/bonfireprocessor/bonfire-soc/tree/master/sdram

you find my slightly modified version which definitely works (tested with a clock frequency of 96Mhz, its best you start with a clock close to it.

When you build a design with it, you should definitely simulate it, there are two different simulation models for the SDRAM chip in the link above, I only have used the sdram_model.vhd yet. With simulation you will also easily understand how the thing works and how to run fast pipelined back-to-back reads or writes.

The DRAM has some advantages over SRAM: 

It requires less adress lines and has 16 Bit width. So the peak throuput is actually nearly twice of a 8 Bit SRAM.

If you are interested in a SRAM based board in the Papilio price range take a look at the Digilent Cmod A7, it works with the newer Artix-7 FPGA and 512KBytes SRAM, otherwise it is quite similar to the Papilio Pro.

 

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