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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>Detect warm/called reset</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/17397/detect-warm-called-reset</link><description> Hello, 
My target is based on AT89C51ED2 and RTX-Tiny. 
I&amp;#39;m trying to detect warm/cold reset. I know that POF bit didn&amp;#39;t work in the RD2 version, so I don&amp;#39;t want to use it here also. 
I defined two global variables one in XDATA and the other one in DATA</description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: Detect warm/called reset</title><link>https://community.arm.com/thread/43106?ContentTypeID=1</link><pubDate>Mon, 08 Nov 2004 12:32:12 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:fbb96191-d6dd-4105-b072-c99b60b5afe4</guid><dc:creator>erik  malund</dc:creator><description>&lt;p&gt;&lt;i&gt;I sow that after cold reset (power up) the values are 0xFF for XDATA and 0x0 for DATA. In the program i change those values to 0x55 and cause to warm reset (by watchdog or hardware reset) I think that in this case I need to receive 0x55 but instead I receive 0xFF in XDATA and 0x0 in DATA.&lt;br /&gt;
Can you tell me why?&lt;/i&gt;&lt;br /&gt;
1) the values after power on reset are indeterminate,thus your method may/will fail.&lt;br /&gt;
2) probably the warm reset result is due to C initializer clearing the DATA and you not having the &amp;#39;set internal xdata&amp;#39; SFR bit set before the startup clears XDATA.&lt;br /&gt;
&lt;br /&gt;
Erik&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>