Dual In-line Adaptor Board?

[leon_heller]

I was intending to raise the issue of the Xtag connector. I favour having it off the module, and connected via the pins. Alternatively, there could be a small connector on the module with just the essential signals on it, and a little adapter could be supplied for the Xtag-2. The former keeps the cost down, at the expense of some I/O. I don't think that many users of this type of product will want lots of I/O, they will mainly be hobbyists. I also intend to provide a prototyping board for the module with a 40-way socket and lots of holes, which would include the XTAG-2 connector, 5V and 3.3V regulators, and a DC input connector. With my favoured solution, there is a problem if people want to use solderless breadboards (I don't like them) in that some sort of adapter will still be needed for the XTAG-2 connections. A solderless breadboard could be mounted on the prototyping board, or a similar board, of course

Leon

[jonathan]

I think one of the big wins of these would be to allow people to use solderless breadboards. If you can find a way to do that I'd already place an order for 5 (at present).

[Folknology]

The problem with adding an smd JTAG is that it requires a JTAG programmer and an extra cable, this can act as a barrier to entry. However there is always a compromise between cost and functionality, what is the impact of adding an XC-5 like usb to the board on cost and board space Leon? Is it feasible to add this?

[JohnR]

Hi,

I may have posted about this before on Xlinkers - there is a very useful company in the USA, (beldynsys.com) that makes a wide range of SMT prototyping adapters. These include snap-apart cards for most types of SMT components as well as bigger prototype boards with a large grid of .100" pitch through-holes as well as a power supply area.

FWIW, I have quite often used their indivual small SMT cards expoxied on to the insulated side of single-sided printed circuit card to make quick prototypes that would fairly closely represent a 'real' PCB.

John

[leon_heller]

I'd rather make it XTAG-2 compatible, to match all future XMOS products. It'll also save the cost of an FTDI chip. Users won't have access to a virtual PC COM port as they do with the XC-5, of course. If they need that they will have to interface an FTDI chip to the module, they are available on convenient break-out boards.

Leon

[Corin]

Hi Leon,

I looked at this a while ago and designed a shcematic with a XS1-L1-64TQFP. Unfortunately due to the size of the package it won't easily fit on a 600mil wide DIP footprint.

I have attached a zipped pdf schematic which has a switch mode core supply, the PLL filtered and connected and the required reset cirucitry. JTAG is on the connector pins rather than having an on board XSYS header. I've used a 25MHz xtal to give a core frequency of 500MHz.

Regards,
Corin

[leon_heller]

Thanks. It's a similar concept.

It would be nice if there was a QFN option for the single-core devices.

Leon

[Folknology]

Agreed on the QFN package, any estimate on pricing for your board Leon? looking forward to seeing it.

@Corin really 500Mhz! is that possible, how fast can it be clocked?

regards
Al

[leon_heller]

Something like £30-£35, hopefully. It depends on how many I get made in a batch. I have a contact in China who might help me get a good manufacturing deal, even for what is a small order by their standards.

Leon

[leon_heller]

I'm thinking of using this Molex connector for the XTAG adapter:

http://uk.rs-online.com/web/search/sear ... &R=5427012

and this cable:

http://uk.rs-online.com/web/search/sear ... &R=4591960

I've just ordered some so that I can check the PCB footprint, and the cable security.

Leon