<html>
<head>
<style>
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 10pt;
font-family:Verdana
}
</style>
</head>
<body class='hmmessage'>
Hi,<BR>
<BR>
I want to post a message in the forum:<BR>
<BR>
<A href="http://www.coreboot.org/pipermail/coreboot/2008-July/036446.html">http://www.coreboot.org/pipermail/coreboot/2008-July/036446.html</A><BR>
<BR>
I am not sure how to post the message. I have written my response below to one of the messages in the forum. Can you help me in posting the message written below.<BR>
<BR>
Regards,<BR>
Hardik Patel<BR>
<BR>
<BR>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">MY RESPONSE TO THE ENGINEER IN THE FORUM:</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Yes, just looking at overhead it does seem that the over head time for AAI is greater than Page Program time. However, overhead time is insignificant compared to overall program time. </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Let’s do a quick compare between the below two cases:</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P><PRE style="MARGIN-LEFT: 1in"><FONT face="Courier New" color=blue size=2><SPAN style="FONT-SIZE: 10pt; COLOR: blue">Programming in AAI needs</SPAN></FONT></PRE><PRE style="MARGIN-LEFT: 1in"><FONT face="Courier New" color=blue size=2><SPAN style="FONT-SIZE: 10pt; COLOR: blue">1(command)+3(dummyaddr)+2(data)+(1(command)+2(data))*127(aaiwrites) =</SPAN></FONT></PRE><PRE style="MARGIN-LEFT: 1in"><FONT face="Courier New" color=blue size=2><SPAN style="FONT-SIZE: 10pt; COLOR: blue">387 cycles for 256 bytes</SPAN></FONT></PRE><PRE style="MARGIN-LEFT: 1in"><FONT face="Courier New" color=blue size=2><SPAN style="FONT-SIZE: 10pt; COLOR: blue"> </SPAN></FONT></PRE><PRE style="MARGIN-LEFT: 1in"><FONT face="Courier New" color=blue size=2><SPAN style="FONT-SIZE: 10pt; COLOR: blue">Page Programming</SPAN></FONT></PRE><PRE style="MARGIN-LEFT: 1in"><FONT face="Courier New" color=blue size=2><SPAN style="FONT-SIZE: 10pt; COLOR: blue">Programming in 256 byte chunks needs 1(command)+3(address)+256(data) =</SPAN></FONT></PRE><PRE style="MARGIN-LEFT: 1in"><FONT face="Courier New" color=blue size=2><SPAN style="FONT-SIZE: 10pt; COLOR: blue">260 cycles for 256 bytes</SPAN></FONT></PRE>
<P class=MsoNormal style="MARGIN-LEFT: 1in"><FONT face=Arial color=black size=2><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">In AAI programming:</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Sending the bytes using the AAI protocol will depend on the clock frequency at which the memory accepts writes. For 50 Mhz clock, 387 cycles would take 387*(1/50Mhz)=7.74us</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Now the memory will take time to do internal programming. For AAI programming, it takes maximum 10us to program 1 word (or two bytes). Hence it would take 10us *127=1.27ms</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">So the total time = 1.27ms + 7.74us=1.27774us. Thus the overhead time is insignificant portion of the total time.</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Now For Page Programming:</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Sending the Page data at 50Mhz clock frequency would take 260*(1/50Mhz) = 5.2us</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Now the memory will take time to do internal programming of the 256bytes which it just received. For example MX25L3235D macronix part would take 1.4ms (typical) to do page programming. </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">So the total time = 1.4ms(typ) + 5.2us = 1.4052ms. </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">THUS, clearly the above calculation suggests that overall time for AAI programming is faster than Page programming. Page programming time can take several milliseconds for many memories. I would prefer AAI.</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"> </SPAN></FONT></P>
<BR>
<BR>
<RTE_TEXT></RTE_TEXT><BR><br /><hr />Win a trip with your 3 best buddies. <a href='http://www.messengerbuddies.ca/?ocid=BUDDYOMATICENCA19' target='_new'>Enter today.</a></body>
</html>