Boot Modes for 3 x XL216 TQ128 design

Technical discussions around xCORE processors (e.g. General Purpose (L/G), xCORE-USB, xCORE-Analog, xCORE-XA).
CousinItt
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Joined: Wed May 31, 2017 6:55 pm

Re: Boot Modes for 3 x XL216 TQ128 design

Postby CousinItt » Fri Dec 07, 2018 4:31 pm

That's very useful - thanks for the update. I've looked for some more info and I can't find much. That snippet from the XN specification I quoted earlier refers to a line of devices, so clearly there should be some way in which it can work. The only other thing I've found is for the first generation devices in XS1 Link Performance and Design Guidelines which shows more than one device booting from a single flash, which says the first bootee has to use X0LB (presumably replaced by XL0 in the XCORE-200) but then adds
All slave devices are connected in the master-ward direction using X0LB
and
Any free outgoing link can then be used to boot further downstream devices.
CousinItt
XCore Addict
Posts: 138
Joined: Wed May 31, 2017 6:55 pm

Postby CousinItt » Mon Feb 04, 2019 10:07 pm

cluster_small.jpg
Well, at last, here it is. Booting from flash works well, and all local links are rock solid at two clocks.

A couple of things I've noted:

1) For the xscope link to work the JTAG connection needs to be really short. I started off with a few more cm of JTAG ribbon cable and no joy.

2) I should have allowed for more flexibility in the VCC supply converter. Power up isn't monotonic, but adding a feedback capacitor and a bigger output cap fixes it. Fortunately there are places I can tack these parts on, and I'll include them properly in the next revision.

At the moment I'm using the IS25LQ016B. I'll also experiment with the LP part.
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