讯享网<span style="font-family:宋体;">在方式0中，波特率为时钟频率的1/12，即fOSC/12，固定不变。在方式2中，波特率取决于PCON中的SMOD值，即波特率为：当SMOD=0时，波特率为fosc/64;当SMOD=1时，波特率为fosc/32。方式1和方式3的波特率可变，由定时器1的溢出率决定。当定时器T1用作波特率发生器时，通常选用定时初值自动重装的工作方式2(注意：不要把定时器的工作方式与串行口的工作方式搞混淆了)。其计数结构为8位，定计数初值为Count，单片机的机器周期为T，则定时时间为(256?Count)×T。<br /> 

一﹑煤矿用阻燃光缆产品用途及特点

<span style="font-family:宋体;">本产品适用于</span><span>485</span><span style="font-family:宋体;">等同性设备数据信号传输。</span><span></span> 

讯享网<span style="font-family:宋体;">二﹑执行标准</span><span></span> 

<span style="font-family:宋体;">参照</span><span>UL AWM 2919</span><span style="font-family:宋体;">文件</span> 

讯享网<span style="font-family:宋体;">三、使用特性</span><span></span> 

<span style="font-family:宋体;">1.</span><span style="font-family:宋体;">电缆长期使用温度：</span><span>-40</span><span style="font-family:宋体;">～</span><span>7</span><span style="font-family:宋体;">0</span><span style="font-family:宋体;">℃</span><span style="font-family:宋体;"></span> 

讯享网<span style="font-family:宋体;">2.</span><span style="font-family:宋体;">环境温度：固定敷设<span>-40</span>℃非固定敷设<span>-15</span>℃。<span></span></span> 

<span style="font-family:宋体;">3.</span><span style="font-family:宋体;">电缆敷设温度：<span><span>&nbsp;&nbsp; </span></span>不低于<span>0</span>℃<span></span></span> 

讯享网<span style="font-family:宋体;">4.</span><span> RS 485</span><span style="font-family:宋体;">通讯电缆</span><span style="font-family:宋体;">型电缆弯曲半径应不小于电缆直径的<span>10</span>倍。<span></span></span> 

<span style="font-family:宋体;">四、煤矿用阻燃光缆型号、名称及用途<span></span></span> 

讯享网<span style="font-family:宋体;">型号：</span><span>RS 485</span> 

<span style="font-family:宋体;">规格：</span><span>3</span><span style="font-family:宋体;">×</span><span>2</span><span style="font-family:宋体;">×</span><span>0.75+1</span><span style="font-family:宋体;">×</span><span>0.2</span><span style="font-family:宋体;"></span> 

讯享网<span style="font-family:宋体;">名称：聚乙绝缘聚氯乙护套</span><span>485</span><span style="font-family:宋体;">通讯电缆</span><span></span> 

<span style="font-family:宋体;">煤矿用阻燃光缆用途：用于</span><span>485</span><span style="font-family:宋体;">等同性设备数据信号传输，使</span><span style="font-family:宋体;">用或固定敷设</span> 

讯享网 <tr> <td style="border-bottom:windowtext 1pt solid;border-left:windowtext 1pt solid;border-top:windowtext 1pt solid;border-right:windowtext 1pt solid;" valign="top" width="152"> <p style="text-align:center;" align="center"> <span style="font-family:宋体;">项目</span> </p> </td> <td style="border-bottom:windowtext 1pt solid;border-left:windowtext 1pt solid;border-top:windowtext 1pt solid;border-right:windowtext 1pt solid;" valign="top" width="72"> <p style="text-align:center;" align="center"> <span style="font-family:宋体;">单位</span> </p> </td> <td style="border-bottom:windowtext 1pt solid;border-left:windowtext 1pt solid;border-top:windowtext 1pt solid;border-right:windowtext 1pt solid;" valign="top" width="74"> <p style="text-align:center;" align="center"> <span>0.2 mm</span><sup><span>2</span></sup> </p> </td> <td style="border-bottom:windowtext 1pt solid;border-left:windowtext 1pt solid;border-top:windowtext 1pt solid;border-right:windowtext 1pt solid;" valign="top" width="74"> <p style="text-align:center;" align="center"> <span>0.75 mm</span><sup><span>2</span></sup> </p> </td> </tr> <tr> <td style="border-bottom:windowtext 1pt solid;border-left:windowtext 1pt solid;border- </div>