Amino and HW_Slices

[dan]

OK look forwards to seeing your proposal.

Regarding the 5V, the G4 is a good bit more expensive than the L series so less good for entry level stuff in that sense.

However as I said before there is nothing standing in the way of a G4 based core board for people who value the 5V capability - we just need to make sure that the connector definitions support the G4 properly.

We are focusing on the L series first because as you may have noticed the dev board support for L1/L2 is not as extensive as it is for the G4, and because the resulting boards will be cheaper.

[Interactive_Matter]

I sketched something in my copy of the repository https://github.com/interactive-matter/h ... nector.rst.
In the end pretty much the same as the XC kist - the longer I think about it the more sense the XC pinout makes to me. But most probably I am missing some important point since you came up with a different solution.

I think you can still (hopefully) understand my point.

I am quite bad at searching connectors and got no real good overview - so take my proposal with a shovel of salt.

The only basic idea is that we can get away with 16 pins and on IDC that is 2*8. An 2*8 connector is 11 pins wide (physical dimension) - so if you add e.g. 4 pins in 2 rows (2 pin positions) with no real function (VCC/GND/NC) you can use a 24 pin IDC connector to access the whole 16bit port (which is currently not possible with the XC kits).

Using quite standard connectors like IDC gives you plenty of mounting options and can be user provided (buy your own). Additionally the IDC connectors make it quite easy to use ribbon cable for connections.

But I think something similar would be true for FFC connectors


Marcus

[dan]

Hi marcus,

Thanks for that proposal. Incidentally you could submit it as a pull request to the xcore repo.

I take the point about having two connectors with incompatible pinout. However I still can't quite see why you'd want four connectors rather than 2 say, if one assumes that the two connectors are compatible. Would you really want to have 4 tiny boards connected to one core? Maybe you would but what are the example applications?

If you contrast the alternate IDC proposal with the PCI connector idea we can get some perspective on the relative costs in terms of dollars and PCB real estate. In the PCI connector case you would have 2 36-pin PCI edge connectors per core, so 4 per L2 core board with 144 pins in total, with some extra space to export JTAG and CLOCK to all daughterboards. The daughtercards would need to have no connectors at all (just teeth), so thats 4 in total.

The alternate IDC proposal, when used with our proposed L2 based core board, would require 8 16-pin connectors on the board (128 pins in total) plus another 8 female ones on the daughtercards for a full population of daughtercards. I'm pretty sure that one 36-pin PCI edge connector is cheaper than one 16-pin male IDC (we are looking at the relative prices now) so the cost difference is really quite significant, and then there is the issue of real estate.

I think the important thing for us to understand at the moment about your proposal, is what unwanted constraints having 2 compatible rather than four compatible connectors would impose for the kinds of projects you are thinking about.

Cheers,

Dan

[Interactive_Matter]

Hi,

having compatible connectors is a very important thing from my point of view.

I designed 4 connectors since I noticed that for most of my purpose some pins are enough - like one or two 12C or SPI connectios, some select bits and so on.
But that point is not very important for me. I just liked the XC pinout because the output ports are due to its relatively small size quite versatile. But having 'just' 2 ports are ok too. Most probably there will be special breakout slices (e.g. X SPI ports, each with CS and one interrupt).

I realy like the idea of using PCI connectors. I think for real applications you would need special plated connection pins, but for just some tests normal pads should be enough.

My only concern regarding PCI is that it is a an obsolete standard and will eventually get hard to get or economically extinct. But then there is still PCIe or similar adapted connectors: http://search.digikey.com/scripts/DkSea ... 09-2025-ND 0,2$@1000 for 36 pins!!!

While researching on connectors I though about alternatively using SATA connectors: You can get them cheap as hell since they are produced in real high volumes. Cables come more or less for free (everybody got one or two laying at home - and they are inexpensive too). Physical connection is quite robust. Unfortunately it is just 22 pins. And eventually somebody will realy connect a HDD ;)
This cost ~1$@1000 http://search.digikey.com/scripts/DkSea ... ND&x=0&y=0

[dan]

My only concern regarding PCI is that it is a an obsolete standard and will eventually get hard to get or economically extinct. But then there is still PCIe or similar adapted connectors: http://search.digikey.com/scripts/DkSea ... 09-2025-ND 0,2$@1000 for 36 pins!!!

Sorry, that is what I meant - the proposal is exactly to use the PCIe connectors as you suggest above.

[TonyD]

@Dan

Have you got a sketch / drawing you could post to help us visualize what's being proposed?

Speaking of connectors, I've always been a big fan of IDC connectors, they're easy to work with and I've always got them in my parts bin. I know as soon as I see a board with FCC connectors I'll have to order them in :(.

[dan]

Hi Tony,

We're working on some kind of space model, made from a combo of cardboard and the connectors in question, and will post some pics in the repo when done. Since we have the following connectors proposed thus far:

* PCIe style 36-pin edge connectors
* FFC surface mount connectors using short flexible ribbon cables.
* IDC connectors of various proposed widths

We'll work on a mock up of each kind to assist visualisation of the competing proposals.

For the FFC ones, XMOS would likely order them in bulk and then distribute them in packs of 5 or 10 which should be very affordable. The IDC connectors would end up adding a good deal more to the overall price than the other two options, but I do recognise their advantages and general popularity.

[Corin]

Please see the new update to the connectors https://github.com/xcore/hw_slicekit_sy ... nector.rst

Cheers,
Corin

[dan]

Corin, is the ULPI bus all collected on one of the two 36-pin connectors? IIRC ULPI involves 8B and 1E, and these are on different connectors according to this update.

[Corin]

No - Henk's view is that a USB slice will use both connectors.

Corin