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<?xml-stylesheet type="text/xsl" href="https://community.arm.com/utility/feedstylesheets/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/"><channel><title>4 ms Glitch</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/33270/4-ms-glitch</link><description> 
Dear all 

 
I recently start programming STM32F103VB Arm based MCU,
writing simple blinking led on my own HW for testing. it was OK, but
i feel something goes wrong, for the reason writing so simple codes
to test the outputs of mcu as follows: 

 </description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: 4 ms Glitch</title><link>https://community.arm.com/thread/117589?ContentTypeID=1</link><pubDate>Tue, 08 Jul 2014 03:38:36 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:3722b80f-5ad1-4e9a-a7f9-c997a2dc096b</guid><dc:creator>Khodadad Namiri</dc:creator><description>&lt;p&gt;&lt;p&gt;
Thanks of all&lt;/p&gt;

&lt;p&gt;
finding that updating option byte in programmer solved my reset
problem.&lt;/p&gt;

&lt;p&gt;
best regards to all&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: 4 ms Glitch</title><link>https://community.arm.com/thread/107784?ContentTypeID=1</link><pubDate>Tue, 08 Jul 2014 01:03:29 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:cb189f01-1c74-4e3c-ba33-8dec2a96b6ce</guid><dc:creator>Khodadad Namiri</dc:creator><description>&lt;p&gt;&lt;p&gt;
I found that IWDG make the system reset by reloadig the register
in while loop;&lt;/p&gt;

&lt;pre&gt;
while (1) IWDG-&amp;gt;KR = 0xAAAA;
&lt;/pre&gt;

&lt;p&gt;
this is not fine code, I&amp;#39;m trying to find a better way to disable
this type reset.&lt;br /&gt;
is there any solution?&lt;/p&gt;

&lt;p&gt;
best regards;&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: 4 ms Glitch</title><link>https://community.arm.com/thread/118512?ContentTypeID=1</link><pubDate>Mon, 07 Jul 2014 08:05:12 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:d914a70c-d9b9-46ad-a3f3-5db4689358cd</guid><dc:creator>Westonsupermare Pier</dc:creator><description>&lt;p&gt;&lt;p&gt;
Would have thought CMSIS code would have called SystemInit()
before main(). The while(1); is fine, it stops the code dropping out
of main() and going who knows where.&lt;/p&gt;

&lt;p&gt;
Is this using some commercial board? or some home brewed
board?&lt;/p&gt;

&lt;p&gt;
If you scope the NRST/NRESET line is it stable and high while this
behaviour is observed?&lt;/p&gt;

&lt;p&gt;
As Per suggests, perhaps you have other code enabling a IWDG or
WWDG.&lt;/p&gt;

&lt;p&gt;
Tried using a debugger?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: 4 ms Glitch</title><link>https://community.arm.com/thread/82000?ContentTypeID=1</link><pubDate>Mon, 07 Jul 2014 06:03:06 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:04c72af1-2d0a-493b-85f3-d559ce92f50d</guid><dc:creator>Khodadad Namiri</dc:creator><description>&lt;p&gt;&lt;p&gt;
Dear Per&lt;/p&gt;

&lt;p&gt;
I placed while loop at the end of main() procedure, but I&amp;#39;m not
sure about W.D. , may be the&lt;br /&gt;
SystemInit(); SystemCoreClockSetHSI(); SystemCoreClockUpdate();
functions enable the W.D.&lt;br /&gt;
which i should check, do you know the exact job of those functions?
(against of W.D.)&lt;/p&gt;

&lt;p&gt;
best Regards&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: 4 ms Glitch</title><link>https://community.arm.com/thread/68785?ContentTypeID=1</link><pubDate>Mon, 07 Jul 2014 05:34:05 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:76b8da4c-d956-4a45-a99f-435fe2363388</guid><dc:creator>ImPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
It behaves more like if the processor constantly restarts.&lt;/p&gt;

&lt;p&gt;
Are you really sure that you do have that while loop at the end of
mail()?&lt;br /&gt;
And that you haven&amp;#39;t any enabled w-dog timer? (Note - you may not
write the word w-a-t-c-h-d-o-g on the forum, because the forum will
then fail to accept your post because of a stupid spam filter
rule).&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>