Guest Tb_

stack of papilio Shield

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Guest Tb_

Hi

Would be possible to build a stack of papilio shield ? The basic idea is if my design doesn't fit in one FPGA. I would like to be able to split it into several FPGA. Which will communicate them self using io pin on the board.

Idealy board would have a configurable switch in order to identify them. So the Arduino could identify papilio Shield and send the correct bitfield in case an update is required.

This kind of feature would be i think very useful, specially to design SoC on FPGA.

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Guest Van

That's a good point, not sure how the Ardunio plays the bitstream, but if we are talking JTAG, being able to add to the device chain would be very nice. Not only for another FPGA but memories and other devices.

Van

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Guest Tb_

Yes there is the jtag chain. But not only. The board should have dedicated IO to allow FPGA inter-connection.

Thomas

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Good idea, I can't think off the top of my head any easy way to have the Arduino program a stack of Papilio Shields.

But I'm going to be adding a Programming Wing header which exposes each Shields JTAG port. Worst case scenario would be that each Shield would have a programming wing and would plug into the USB port independently.

Then the only question becomes whether the 3.3V and 5V pins on the Wing Slots need to be disconnected or if the power supplies can handle any potential reverse current from the other Shields 3.3V and 5V power supplies...

It should be doable but while probably need a little hacking to make it happen.

Jack.

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Guest Tb_

I don't know very well jtag but it is possible to connect several chip (memory, fpga,avr) and program then. At least it is was what i understood... i may be wrong.

May be dedicated hw ressource should reserved for this task ... or a dedicated board for next project

I already plug 2 7805 to increase output current and avoid thermal shunt.

I didn't check what you actually plan to use as regulator. But i expect that they work similar.

Thomas

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For a JTAG chain to work the JTAG pins have to be daisy chained which makes things a lot more complicated. Probably not going to attempt for this board at least. :)

Jack.

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