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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>Contents of not initialized memory</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/14935/contents-of-not-initialized-memory</link><description> Hello! 
 
Here is a general question that probably doesn&amp;#39;t have a definite answer: 
 
What data does memory (static RAM) hold if it never was initialized? What I mean is if the controller boards (with external S-RAM) are manufactured, then a software</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: Contents of not initialized memory</title><link>https://community.arm.com/thread/38614?ContentTypeID=1</link><pubDate>Tue, 16 Apr 2002 11:19:00 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:c771ec2a-19ea-4702-9ad8-2481c03d79a8</guid><dc:creator>Andy Neil</dc:creator><description>&lt;p&gt;The content of SRAM after powerup is &lt;i&gt;udefined&lt;/i&gt; - that is, it could be &lt;i&gt;anything,&lt;/i&gt; and it doesn&amp;#39;t have to be repeatable or predictable.&lt;br /&gt;
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This is why embedded code must &lt;b&gt;never&lt;/b&gt; use a variable before it has been initialised (whether explicitly in your code, or by your startup routines).&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: Contents of not initialized memory</title><link>https://community.arm.com/thread/38613?ContentTypeID=1</link><pubDate>Tue, 16 Apr 2002 11:15:28 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:7512fb09-7a28-47cb-a1be-a79b7cb63cb4</guid><dc:creator>Mark Odell</dc:creator><description>&lt;p&gt;SRAM will hold whatever random value that the device will hold after power is applied. One doesn&amp;#39;t have to &amp;quot;initialize&amp;quot; SRAM anyhow. SDRAM, requires an init. sequence before it can be used. &lt;br /&gt;
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If this is C related, all file scoped variables are either zeroed by the C run-time (.bss) or set to a particular value by the C run-time (.data). Automatic variables are indeterminate and should always be set before use.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: Contents of not initialized memory</title><link>https://community.arm.com/thread/38610?ContentTypeID=1</link><pubDate>Tue, 16 Apr 2002 10:43:56 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:3b87da13-988b-41f3-a926-75ab87dc30b3</guid><dc:creator>Walt Conley</dc:creator><description>&lt;p&gt;Hi Holger:&lt;br /&gt;
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I cannot really answer your question but the rule of thumb I usually follow is to never count on things that are not absolutely guaranteed in the data sheet of the device I&amp;#39;m using.&lt;br /&gt;
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-Walt&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>