单片机坐标简易电子琴的设计.htm

http://www.edacn.net/cgi-bin/forums.cgi?forum=7&topic=9127下,则R3～R0的输出信号中会有一个为1,但我们还是是无法确定哪一个键被按下,必須要

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                      <TD align=middle><FONT style="FONT-SIZE: 11pt" 
                        color=#000000>简易电子琴的设计</FONT></TD></TR></TBODY></TABLE><BR><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"><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><o:p>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt 21pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo1; tab-stops: list 21.0pt"><SPAN><SPAN 
                  style="mso-list: Ignore"><FONT face="Times New Roman">一、<SPAN 
                  style="FONT: 7pt 'Times New Roman'"><FONT 
                  size=3>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
                  </FONT></SPAN></FONT></SPAN>设计题目：</SPAN><SPAN 
                  lang=EN-US><o:p></o:p></SPAN></P>
                  <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 21pt"><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设计一简易电子琴，要求能够发出</SPAN><SPAN 
                  lang=EN-US><FONT face="Times New Roman">1</FONT></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><FONT face="Times New Roman">2</FONT></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><FONT face="Times New Roman">3</FONT></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><FONT face="Times New Roman">4</FONT></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><FONT face="Times New Roman">5</FONT></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><FONT face="Times New Roman">6</FONT></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><FONT face="Times New Roman">7</FONT></SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等七个音符。</SPAN></P>
                  <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 21pt"><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">使用元件：</SPAN><SPAN 
                  lang=EN-US><FONT face="Times New Roman">AT<st1:chmetcnv 
                  UnitName="C" SourceValue="89" HasSpace="False" 
                  Negative="False" NumberType="1" TCSC="0" 
                  w:st="on">89C</st1:chmetcnv>51</FONT></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><FONT 
                  face="Times New Roman">LM324</FONT></SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，喇叭，按键等</SPAN></P>
                  <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 21pt"><SPAN 
                  lang=EN-US><o:p><FONT 
                  face="Times New Roman">&nbsp;</FONT></o:p></SPAN></P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt 21pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo1; tab-stops: list 21.0pt"><SPAN><SPAN 
                  style="mso-list: Ignore"><FONT face="Times New Roman">二、<SPAN 
                  style="FONT: 7pt 'Times New Roman'"><FONT 
                  size=3>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
                  </FONT></SPAN></FONT></SPAN>设计目的</SPAN><SPAN 
                  lang=EN-US><o:p></o:p></SPAN></P>
                  <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 21pt"><SPAN 
                  lang=EN-US><SPAN style="mso-spacerun: yes"><FONT 
                  face="Times New Roman">&nbsp; </FONT></SPAN></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><FONT face="Times New Roman">1</FONT></SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）能够对电子电路、电子元器件、印制电路板等方面的知识有进一步的认识，独立对其进行测试与检查。</SPAN></P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt 21pt; TEXT-INDENT: 14.9pt; mso-para-margin-left: 2.0gd; mso-char-indent-count: 1.42"><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><FONT face="Times New Roman">2</FONT></SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）熟悉</SPAN><SPAN 
                  lang=EN-US><FONT 
                  face="Times New Roman">8051</FONT></SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">单片机的内部结构和功能，合理使用其内部寄存器，能够完成相关软件编程设计工作。</SPAN></P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt 21pt; TEXT-INDENT: 14.9pt; mso-para-margin-left: 2.0gd; mso-char-indent-count: 1.42"><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><FONT face="Times New Roman">3</FONT></SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）为实现预期功能，能够对系统进行快速的调试，并能够对出现的功能故障进行分析，及时修改相关软硬件。</SPAN></P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt 21pt; TEXT-INDENT: 14.9pt; mso-para-margin-left: 2.0gd; mso-char-indent-count: 1.42"><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><FONT face="Times New Roman">4</FONT></SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）对软件编程、排错调试、焊接技术、相关仪器设备的使用技能等方面得到较全面的锻炼和提高。</SPAN></P>
                  <P class=MsoNormal 
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                  style="mso-list: Ignore"><FONT face="Times New Roman">三、<SPAN 
                  style="FONT: 7pt 'Times New Roman'"><FONT 
                  size=3>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
                  </FONT></SPAN></FONT></SPAN>系统硬件图</SPAN></P>
                  <P class=MsoNormal 
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                  id=_x0000_t75 coordsize="21600,21600" o:spt="75" 
                  o:preferrelative="t" path="m@4@5l@4@11@9@11@9@5xe" filled="f" 
                  stroked="f">&nbsp;<IMG 
                  style="BORDER-LEFT-COLOR: #000000; FILTER: ; BORDER-BOTTOM-COLOR: #000000; BORDER-TOP-COLOR: #000000; BORDER-RIGHT-COLOR: #000000" 
                  alt="" src="单片机坐标简易电子琴的设计.files/200512058933000.jpg" 
                  border=0></v:shapetype></SPAN></SPAN></P>
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                  lang=EN-US 
                  style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><v:shapetype 
                  coordsize="21600,21600" o:spt="75" o:preferrelative="t" 
                  path="m@4@5l@4@11@9@11@9@5xe" filled="f" 
                  stroked="f">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
                  流程图:</v:shapetype></SPAN></SPAN></P>
                  <P class=MsoNormal 
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                  lang=EN-US 
                  style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><v:shapetype 
                  coordsize="21600,21600" o:spt="75" o:preferrelative="t" 
                  path="m@4@5l@4@11@9@11@9@5xe" filled="f" 
                  stroked="f">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<IMG 
                  style="BORDER-LEFT-COLOR: #000000; FILTER: ; BORDER-BOTTOM-COLOR: #000000; BORDER-TOP-COLOR: #000000; BORDER-RIGHT-COLOR: #000000" 
                  alt="" src="单片机坐标简易电子琴的设计.files/200512059038000.gif" 
                  border=0></v:shapetype></SPAN></SPAN></P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt 21pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo1; tab-stops: list 21.0pt"><SPAN><SPAN 
                  lang=EN-US 
                  style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><v:shapetype 
                  coordsize="21600,21600" o:spt="75" o:preferrelative="t" 
                  path="m@4@5l@4@11@9@11@9@5xe" filled="f" stroked="f"><IMG 
                  style="BORDER-LEFT-COLOR: #000000; FILTER: ; BORDER-BOTTOM-COLOR: #000000; BORDER-TOP-COLOR: #000000; BORDER-RIGHT-COLOR: #000000" 
                  alt="" src="单片机坐标简易电子琴的设计.files/200512059057000.jpg" 
                  border=0></v:shapetype></SPAN></SPAN></P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt 21pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo1; tab-stops: list 21.0pt"><SPAN><SPAN 
                  lang=EN-US 
                  style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><v:shapetype 
                  coordsize="21600,21600" o:spt="75" o:preferrelative="t" 
                  path="m@4@5l@4@11@9@11@9@5xe" filled="f" 
                  stroked="f">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 原理:</P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt 57pt; TEXT-INDENT: -36pt; mso-list: l0 level2 lfo1; tab-stops: list 57.0pt"><SPAN 
                  lang=EN-US style="mso-bidi-font-family: 宋体"><SPAN 
                  style="mso-list: Ignore">（一）<SPAN 
                  style="FONT: 7pt 'Times New Roman'">&nbsp;&nbsp; 
                  </SPAN></SPAN></SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">音乐产生原理及硬件设计</SPAN></P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt"><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">由于一首音乐是许多不同的音阶组成的，而每个音阶对应着不同的频率，这样我们就可以利用不同的频率的组合，即可构成我们所想要的音乐了，当然对于单片机来产生不同的频率非常方便，我们可以利用单片机的定时</SPAN><SPAN 
                  lang=EN-US>/</SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">计数器</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'">来产生这样方波频率信号，因此，我们只要把一首歌曲的音阶对应频率关系弄正确即可。</SPAN></P>
                  <P class=MsoNormal 
                  style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt"><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">本次设计中单片机晶振为</SPAN><SPAN 
                  lang=EN-US>12MHZ</SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，那么定时器的计数周期为</SPAN><SPAN 
                  lang=EN-US>1MHZ</SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，假如选择工作方式</SPAN><SPAN 
                  lang=EN-US>1</SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，那</SPAN><SPAN 
                  lang=EN-US>T</SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">值便为</SPAN><SPAN 
                  lang=EN-US>T= 2<SUP>16</SUP>--5</SPAN><SPAN 
                  style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">﹡</SPAN><SPAN