📄 p16mem.htm

📁 著名的《tcplean》的配套光盘
💻 HTM
字号:
<!DOCTYPE HTML PUBLIC "-//SoftQuad Software//DTD HoTMetaL PRO 6.0::19990601::extensions to HTML 4.0//EN" "hmpro6.dtd">
<HTML> 
  <HEAD> 
	 <TITLE>ChipWeb memory usage</TITLE> 
  </HEAD> 
  <BODY> 
	 <H3>Iosoft Ltd. - ChipWeb memory usage</H3> 
	 <H4>PIC16F877 and PCW compiler</H4> 
	 <P>The following table gives an indication of the memory used by the
		various ChipWeb protocols in the PIC16F877, when using the Custom Computer
		Services PCW compiler. Due to the tight integration between the various
		software components, and the way the compiler overlays the local variables from
		various functions, these figures can only serve as a rough guide. Relatively
		minor modifications to the standard code can have a significant effect on
		memory usage, so it is strongly recommended that you perform your own tests
		when seeking to establish whether a specific protocol will fit in the target
		device.</P> 
	 <P>The figures (in bytes) were obtained from the PCW compiler using the
		standard ChipWeb software with the relevant protocols disabled; the RAM value
		is the 'worst-case' figure. The low RAM sizes are a result of 'on-the-fly'
		message parsing techniques, and the extensive re-use of the Ethernet buffers by
		higher-level functions.</P> 
	 <TABLE BORDER="1"> 
		<TR> 
		  <TH>Protocol</TH> 
		  <TH>ROM</TH> 
		  <TH> RAM</TH> 
		</TR> 
		<TR> 
		  <TD>Ethernet drivers</TD> 
		  <TD>988</TD> 
		  <TD>134</TD> 
		</TR> 
		<TR> 
		  <TD>IP</TD> 
		  <TD>301</TD> 
		  <TD>38</TD> 
		</TR> 
		<TR> 
		  <TD>ARP</TD> 
		  <TD>636</TD> 
		  <TD>0</TD> 
		</TR> 
		<TR> 
		  <TD>ICMP</TD> 
		  <TD>562</TD> 
		  <TD>2</TD> 
		</TR> 
		<TR> 
		  <TD>TCP (stateless)</TD> 
		  <TD>1159</TD> 
		  <TD>6</TD> 
		</TR> 
		<TR> 
		  <TD>HTTP</TD> 
		  <TD>146</TD> 
		  <TD>6</TD> 
		</TR> 
		<TR> 
		  <TD>File handling</TD> 
		  <TD>1069</TD> 
		  <TD>28</TD> 
		</TR> 
		<TR> 
		  <TD>Analog I/Ps</TD> 
		  <TD>108</TD> 
		  <TD>0</TD> 
		</TR> 
		<TR> 
		  <TD>User interface</TD> 
		  <TD>1505</TD> 
		  <TD>0</TD> 
		</TR> 
		<TR> 
		  <TD>LCD &amp; serial </TD> 
		  <TD>377</TD> 
		  <TD>0</TD> 
		</TR> 
		<TR> 
		  <TD><B>TOTAL</B></TD> 
		  <TD><B>6851</B></TD> 
		  <TD><B>214</B></TD> 
		</TR> 
	 </TABLE> 
	 <P>If SLIP drivers are used instead of Ethernet, they occupy around 1400
		bytes of code space and 180 bytes of RAM, though there is an overall decrease
		in code size to 5810 bytes ROM, and increase to 308 bytes RAM. Note that the
		Ethernet and SLIP Web servers have differing functionality, so this is not a
		strictly like-for-like comparison.</P>
	 <P>&copy; Iosoft Ltd 2001</P> </BODY>
</HTML>
⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -