8051外部接口.htm

51 bian cheng bang zhu

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  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>I</span></p>
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  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>I</span></p>
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  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>I</span></p>
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  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
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  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>I</span></p>
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  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
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  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>O</span></p>
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  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
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  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>O</span></p>
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 </tr>
 <tr style='mso-yfti-irow:3;mso-yfti-lastrow:yes'>
  <td width=63 valign=top style='width:47.3pt;border:solid windowtext 1.0pt;
  border-top:none;mso-border-top-alt:solid windowtext .5pt;mso-border-alt:solid windowtext .5pt;
  padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span
  style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
  "Times New Roman"'>位寻址</span></p>
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  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
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  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>B0</span></p>
  </td>
  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
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  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>B1</span></p>
  </td>
  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>B2</span></p>
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  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>B3</span></p>
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  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
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  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>B4</span></p>
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  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
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  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>B5</span></p>
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  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
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  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>B6</span></p>
  </td>
  <td width=63 valign=top style='width:47.35pt;border-top:none;border-left:
  none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
  mso-border-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=EN-US>B7</span></p>
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<p class=MsoNormal><span lang=EN-US><o:p>&nbsp;</o:p></span></p>

<p class=MsoNormal><span style='font-size:12.0pt;font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>控制线：</span><span
lang=EN-US style='font-size:12.0pt'><o:p></o:p></span></p>

<p class=MsoNormal><span lang=EN-US>~PSEN</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>：外部存储器读选通信号。读</span><span
lang=EN-US>ROM</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>时自动发出负脉冲，作为外部</span><span lang=EN-US>ROM</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>选通信号。</span></p>

<p class=MsoNormal style='margin-top:0cm;margin-right:305.95pt;margin-bottom:
0cm;margin-left:21.0pt;margin-bottom:.0001pt;mso-para-margin-top:0cm;
mso-para-margin-right:29.14gd;mso-para-margin-bottom:0cm;mso-para-margin-left:
21.0pt;mso-para-margin-bottom:.0001pt;text-indent:-21.0pt;mso-char-indent-count:
-2.0'><span lang=EN-US>ALE/~PROG</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>ALE</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>是地址锁存信号。</span><span lang=EN-US>~PROG</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>是</span><span lang=EN-US>8751</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>内部</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"'>编程时的编程脉冲输入端，</span><span lang=EN-US>ALE</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>用来锁存</span><span lang=EN-US>P0</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>送出的低</span><span
lang=EN-US>8</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>位地址信号，当不访问外存储器时输出</span><span
lang=EN-US>1/6</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>的晶振频率。</span></p>

<p class=MsoNormal style='margin-top:0cm;margin-right:305.95pt;margin-bottom:
0cm;margin-left:26.25pt;margin-bottom:.0001pt;mso-para-margin-top:0cm;
mso-para-margin-right:29.14gd;mso-para-margin-bottom:0cm;mso-para-margin-left:
26.25pt;mso-para-margin-bottom:.0001pt;text-indent:-26.25pt;mso-char-indent-count:
-2.5'><span lang=EN-US>~EA/VPP</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>~EA</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>是访问程序存储器控制信号，</span><span lang=EN-US>VPP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>是</span><span lang=EN-US>8751</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>编程时的</span><span
lang=EN-US>21V</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>电压输入端，当</span><span lang=EN-US>~EA</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>为低电平时访问限定在片外程序存储器，而当</span><span lang=EN-US>~EA</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>为高电平时</span><span lang=EN-US>CPU</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>访问限于片内</span><span lang=EN-US>ROM 4K</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>以下空间和自动延伸至片外</span><span lang=EN-US>4K</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>以上空间。</span></p>

<p class=MsoNormal style='margin-top:0cm;margin-right:305.95pt;margin-bottom:
0cm;margin-left:26.25pt;margin-bottom:.0001pt;mso-para-margin-top:0cm;
mso-para-margin-right:29.14gd;mso-para-margin-bottom:0cm;mso-para-margin-left:
26.25pt;mso-para-margin-bottom:.0001pt;text-indent:-26.25pt;mso-char-indent-count:
-2.5'><span lang=EN-US>RST/Vpd</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>RST</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>是复位输入端，</span><span lang=EN-US>2</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>个机器周期以上高电平复位。</span><span lang=EN-US>VPD</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>是备用电源输入端，当</span><span lang=EN-US>VCC</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>下降到一定电压或断电时，通过</span><span lang=EN-US>VPD</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>向片内</span><span lang=EN-US>RAM</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>提供电源，保持数据不丢失。</span></p>

<p class=MsoNormal style='margin-top:0cm;margin-right:305.95pt;margin-bottom:
0cm;margin-left:35.0pt;margin-bottom:.0001pt;mso-para-margin-top:0cm;
mso-para-margin-right:29.14gd;mso-para-margin-bottom:0cm;mso-para-margin-left:
35.0pt;mso-para-margin-bottom:.0001pt;text-indent:-35.0pt;mso-char-indent-count:
-2.5'><span lang=EN-US style='font-size:14.0pt;color:red'>89C2051/1051</span><span
style='font-size:14.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman";color:red'>：</span><span lang=EN-US
style='font-size:14.0pt;color:red'><o:p></o:p></span></p>

<p class=MsoNormal><span lang=EN-US><o:p>&nbsp;</o:p></span></p>

<p class=MsoNormal><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>内部有模拟比较器相比较的信号由</span><span
lang=EN-US>P1.1(AIN0)</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>P1.0(AIN1)<span style='mso-no-proof:yes'> </span></span><!--[if gte vml 1]><v:shapetype
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lang=EN-US><o:p></o:p></span></p>

<p class=MsoNormal style='margin-top:0cm;margin-right:305.95pt;margin-bottom:
0cm;margin-left:26.25pt;margin-bottom:.0001pt;mso-para-margin-top:0cm;
mso-para-margin-right:29.14gd;mso-para-margin-bottom:0cm;mso-para-margin-left:
26.25pt;mso-para-margin-bottom:.0001pt;text-indent:-26.25pt;mso-char-indent-count:
-2.5'><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>输入</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"'>而输出由内部引脚</span><span lang=EN-US>P3.6</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>输出</span><span lang=EN-US>;</span><span lang=EN-US
style='font-size:14.0pt;color:red'><o:p></o:p></span></p>

<p class=MsoNormal><span lang=EN-US><o:p>&nbsp;</o:p></span></p>

<p class=MsoNormal style='margin-left:220.5pt'><span lang=EN-US><o:p>&nbsp;</o:p></span></p>

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