📄 ——单片机系统在测控领域的稳定性探讨.htm
字号:
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">非</SPAN><SPAN
lang=EN-US>EPROM</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">地址选通信号</SPAN></P></DIV></TD></TR></TBODY></TABLE></v:textbox></v:shape></v:group><SPAN
lang=EN-US> <IMG
src="——单片机系统在测控领域的稳定性探讨.files/picrad254DB.gif"></SPAN><BR
style="mso-ignore: vglayout" clear=all></P>
<P class=MsoNormal
style="TEXT-INDENT: 21pt; mso-char-indent-count: 2.0; mso-char-indent-size: 10.5pt"><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">我们也可通过硬件的方法用一个缓冲器直接给数据线写一个值，其原理与上述方法相同。</SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 36.75pt; TEXT-INDENT: -21pt; mso-list: l1 level2 lfo2"><B><SPAN
lang=EN-US
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">三、<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></B><B><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">软件看门狗技术</SPAN><SPAN
lang=EN-US><o:p></o:p></SPAN></B></P>
<P class=MsoNormal
style="TEXT-INDENT: 21pt; mso-char-indent-count: 2.0; mso-char-indent-size: 10.5pt"><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">我们知道看门狗的作用就是防止程序发生死循环，或者说程序跑飞。硬件看门狗是利用了一个定时器，来监控主程序的运行，也就是说在主程序的运行过程中，我们要在定时时间到之前对定时器进行复位如果出现死循环，或者说</SPAN><SPAN
lang=EN-US>PC</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">指针不能回来。那么定时时间到后就会使单片机复位。</SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 15.75pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5; mso-char-indent-size: 10.5pt"><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">软件看门狗技术的原理和这差不多，只不过是用软件的方法实现，我们还是以</SPAN><SPAN
lang=EN-US>51</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">系列来讲，我们知道在</SPAN><SPAN
lang=EN-US>51</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">单片机中有两个定时器，我们就可以用这两个定时器来对主程序的运行进行监控。我们可以对</SPAN><SPAN
lang=EN-US>T0</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设定一定的定时时间，当产生定时中断的时候对一个变量进行赋值，而这个变量在主程序运行的开始已经有了一个初值，在这里我们要设定的定时值要小于主程序的运行时间，这样在主程序的尾部对变量的值进行判断，如果值发生了预期的变化，就说明</SPAN><SPAN
lang=EN-US>T0</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中断正常，如果没有发生变化则使程序复位。</SPAN></P>
<P class=MsoNormal
style="MARGIN-LEFT: 15.75pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5; mso-char-indent-size: 10.5pt"><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对于</SPAN><SPAN
lang=EN-US>T1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">我们用来监控主程序的运行，我们给</SPAN><SPAN
lang=EN-US>T1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设定一定的定时时间，在主程序中对其进行复位，如果不能在一定的时间里对其进行复位，</SPAN><SPAN
lang=EN-US>T1 </SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的定时中断就会使单片机复位。在这里</SPAN><SPAN
lang=EN-US>T1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的定时时间要设的大于主程序的运行时间，给主程序留有一定的的裕量。而</SPAN><SPAN
lang=EN-US>T1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的中断正常与否我们再由</SPAN><SPAN
lang=EN-US>T0</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">定时中断子程序来监视。这样就够成了一个循环，</SPAN><SPAN
lang=EN-US>T0</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">监视</SPAN><SPAN
lang=EN-US>T1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，</SPAN><SPAN
lang=EN-US>T1</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">监视主程序，主程序又来监视</SPAN><SPAN
lang=EN-US>T0</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，从而保证系统的稳定运行。</SPAN></P>
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style="MARGIN-LEFT: 15.75pt; TEXT-INDENT: 26.25pt; mso-char-indent-count: 2.5; mso-char-indent-size: 10.5pt"><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">作者联系：
<A
href="mailto:zc_wang765@sina.com">zc_wang765@sina.com</A></SPAN></P>
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