Choosing a USB development board Topic is solved

[hessa59]

I am getting reasonably comfortable with the startkit and want to move on to a development board that supports USB.
I want to eventually create an instrumentation product that has a GUI on a PC that is written in C#
The PC will communicate with a custom XMOS board using full speed USB

I think that the sweet spot for price/ performance would be an XU series processor but there doesn't seem to be a development board based on the XU series.

The development boards I am considering are :

1) Xcore-200 slicekit (XK-Sk-200-ST)

My concerns are:
a) that this product is very new and there doesn't seem to be a lot of documentation or software support
b)It seems very expensive relative to KIT DEV FOR XE216 Family
c) does it work with all previous slicecards designed for the xs1 slicekit?
d) can I use the existing code base and forum information that pertains to the XS! slice kit? Ie can the xsofttip code be used with it?

2) XCORE-200 explorerKIt

a) this seems to have the same processing power as the XORE-200 slicekit at about half price . If you don't need to use slice boards this seems the way to go.
b)Is there a large amount of code and knowledge base available for this product?
c) I notice that Digikey and Farnell have no stock for this board. Is it declining in popularity.
d) Is it being phased out?

Any help would be greatly appreciated!

[mon2]

XCORE-200 explorerKIt

Pros:

XCORE-200 Series and is current technology
Suitable for USB interfacing
Fair price
USB demos work with this tool (we confirmed a few of them included USB CDC demo)

Cons:

Cannot use SliceBoards 'out of the box'
Believe this tool is EOL but some stock is incoming for August @ Farnell (see their landing page)
No stock

Xcore-200 slicekit (XK-Sk-200-ST)

Pros:

XCORE-200 Series and is current technology
Suitable for USB interfacing
Suitable for SliceBoard interfacing that may work 'out of the box' or with some rework of the source code
USB demos should work with this tool
In stock with Digikey (perhaps others as well)
Includes a few slice boards

Cons:

Expensive

I think that the sweet spot for price/ performance would be an XU series processor but there doesn't seem to be a development board based on the XU series.

There is, but also believed to be EOL. Grab one while you can:

https://www.digikey.com/product-detail/ ... ND/4841595

Pros:

Suitable for USB interfacing
Suitable for SliceBoard interfacing that should work 'out of the box' or with some rework of the source code
USB demos should work with this tool (we recall testing a few demos with USB on this tool)
In stock with Digikey (but believed to be EOL)
Fair price

Cons:

Older XS1 architecture
EOL status (do confirm)
You may be paying a premium for this device vs. the more recent XCORE-200 CPU devices which offer even more features

Regardless, BE SURE to review the datasheets for the inrush current protection required for the VBUS line. Many developers have reported their XMOS CPU devices being killed due to capacitive loading of filter caps and other related transients on the VBUS cpu pin. Further to my ranting and raving on the use of the Diodes Inc. AP2822 USB load switch which should serve an equal or better than the passive parts in the datasheet, be sure to review which footprint is actually shipping from Diodes Inc. and compare the costs of each. Placing a single IC for such protection will be a lower automated assembly cost vs. use of multiple passives.

For example (we got nabbed by the pinout error), AP2822AK is NOT the same pinout as AP2822AKA. Also a large cost difference. AP2822AKA is under $ 0.10 USD while AP2822AK is around $ 0.60 USD - even in T&R volumes. AP2822AKA is stock (at this time of writing); AP2822AK has a 12 week lead time.

Always test the device on lab protos before launching into volume and consider bypass / alternate sourcing of such protection devices to account for vendor shortages.

[hessa59]

Hi mon2

Thanks for your detailed reply.
When I was refering to the XU series I meant xcore-200 chips as opposed to XS1-U. I agree that these offer less functionality without any cost savings.

One Xcore200 chip that looks good is the XU208-256-QF48-C10 at 11.73 in quantities of 490.

There doesn't seem to be a listing for singles of this chip. How would one go about creating a proof of concept board?

Thanks for the heads up on the VBus problem. I assume this applies to USB enabled chips of all XMOS families?

I may have to go with xcore-200 slicekit and hope that the old slicekit code can be made to work without major head aches!

Thanks Again :)

[mon2]

Closest match with stock to your criteria are the following:

XUF208-256-TQ64-C10 (internal flash; 64 pin TQFP)

https://www.digikey.com/product-detail/ ... ND/5358025


XU208-256-TQ64-C10 (no internal flash; 64 pin TQFP)

https://www.digikey.com/product-detail/ ... ND/5148722

I assume this applies to USB enabled chips of all XMOS families?

Recommend this review and solution for all USB based designs for any piece of silicon. See here on the scope captures that confirm the voltage spikes seen by the Vbus rail:

https://www.xcore.com/viewtopic.php?t=5808
* see how the voltage spikes change with the capacitive loads on this line which are dangerous to the CPU

** adding **

http://www.xcore.com/viewtopic.php?f=7&t=5591

[hessa59]

Hi mon2

Thanks I made a mistake when applying the filter at Digikey.
Doesn't look like single quantities will be a problem!

[mon2]

Don't forget about Future Electronics who has stock of the XE216 in TQFP128 package (USB is also available on this version of the device):

http://www.futureelectronics.com/en/CSR ... uage=en-US

[hessa59]

Thanks that's amazing! So far I have only been looking at Farnell and Digikey for XMOS parts.

I am shopping in Canadian dollars. Here are my price search results as of June 29/2017 for single quantities of the XE216-512-128-C20

Digikey $25.13 https://www.digikey.ca/products/en?keyw ... in%20stock

Farnell $25.22 not in stock http://canada.newark.com/xmos/xe216-512 ... a%2Fsearch

Future $13.27 in stock http://www.futureelectronics.com/en/CSR ... uage=en-CA

If I could get the XE chips at the $13 price level when I have completed the project they would certainly be a viable solution!

My concern is that this price may be a one time thing. However I can see that overall bang for the buck is going to be with the xcore-200 parts.

I will probably have to go with the New Slicekit. I am waiting to hear from XMOS sales re it's compatibility with older slicecards and sample code

[mon2]

We are also Canadian. Future can hit and beat your targets for the XE216 devices. Let us know if you require specific contacts @ Future for this line. We work with reps in Toronto (outside reps) and Montreal (inside).

We sourced:

XE216-512-TQ128-C20

XE216-512-FB236-C20

and others through Future.

[hessa59]

Yes I would certainly be interested in the contact information.

Although it may be sometime before I am ready to order the chips in quantity.