XU216 memory range guarenteed to be untouched and DFU

Technical discussions around xCORE processors (e.g. General Purpose (L/G), xCORE-USB, xCORE-Analog, xCORE-XA).
cl-b
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XU216 memory range guarenteed to be untouched and DFU

Postby cl-b » Wed Jan 09, 2019 2:44 pm

Hi,

What is the memory zone not affected by the tools on XU216 processor ?

Based on dfu.xc file I suppose that the range is 0x7FFC8 to 0x7FFFF. After receiving a XMOS_DFU_RESETINTODFU command I write specific pattern in this area, but after CPU reset this area is most of the time reset to 0.
How to explain that this supposed area is reset after a CPU reset writing in PLL register ?

I try to write directly in this area just before reboot and the result is the same

#define FLAG_ADDRESS 0x7FFCC

unsigned x =0x11042011;
asm volatile("stw %0, %1[0]" :: "r"(x), "r"(FLAG_ADDRESS));
device_reboot(c_audioControl);


I also test removing the pattern writing in DFU handler, but the area is always reset to 0 after reboot

Any ideas how to explain this problem ?
cl-b
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Posts: 29
Joined: Fri Sep 15, 2017 2:58 pm

Postby cl-b » Thu Jan 17, 2019 6:38 pm

Nobody to explain at least how this zone is set to 0 (except by a voluntary writing) ?

Thanks
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mon2
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Postby mon2 » Fri Jan 18, 2019 5:17 pm

I think it will be best for you to raise a support ticket using the xmos.com website so that the proper staff member can reply on this low level technical question. On a privileged few will know the correct answer. Please update this post once you receive a reply.

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