<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:st1="urn:schemas-microsoft-com:office:smarttags" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<meta name=Generator content="Microsoft Word 11 (filtered medium)">
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="country-region"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="place"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="PersonName"/>
<!--[if !mso]>
<style>
st1\:*{behavior:url(#default#ieooui) }
</style>
<![endif]-->
<style>
<!--
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}
p
{mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:0cm;
font-size:12.0pt;
font-family:"Times New Roman";}
span.E-postmall17
{mso-style-type:personal-compose;
font-family:Arial;
color:windowtext;}
@page Section1
{size:595.3pt 841.9pt;
margin:70.85pt 70.85pt 70.85pt 70.85pt;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body lang=SV link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>There are several bad programming tricks out there
but this one was new for me:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>The purpose is to clear a memory area in a FLASH
card. The code has an ordinary function that writes a data block to the flash
card.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>The function has two parameters, sector number and a
pointer to the 512 bytes large vector with data.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>To clear the sector this should be the typical
method:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>for (loop=0;loop<512;loop++)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>{<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> sectorArray[loop]=0;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> SdFlashWriteSector(sector, sectorArray);<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>}<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>But instead this is how it is done:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>sectorArray = POINTER_OUTSIDE_RAM;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>SdFlashWriteSector(sector, sectorArray);<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>The code uses the fact that reading an area outside
the actual RAM area will return a fixed value. I guess that on most system this
will fill the FLASH with 0xFF and not 0 but 0xFF is the same as an erased
memory card so that may be on purpose.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>The original name of the pointer POINTER_OUTSIDE_RAM
was not so self informative so this took some time to figure out.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Greatings,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Bengt<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<table class=MsoTableGrid border=0 cellspacing=0 cellpadding=0
style='margin-left:.4pt;border-collapse:collapse'>
<tr height=15 style='height:11.25pt'>
<td width=387 colspan=4 height=15 valign=top style='width:290.4pt;border:
none;border-top:solid windowtext 1.5pt;padding:0cm 3.5pt 0cm 3.5pt;
height:11.25pt'>
<p style='margin-left:-.4pt'><st1:PersonName ProductID="Bengt Ragnemalm"
w:st="on"><b><font size=3 face="Times New Roman"><span style='font-size:12.0pt;
font-weight:bold'>Bengt Ragnemalm</span></font></b></st1:PersonName><b><span
style='font-weight:bold'>,</span></b><font size=2><span style='font-size:
10.0pt'> Forskningsingenjör</span></font><b><span style='font-weight:bold'><o:p></o:p></span></b></p>
</td>
<td width=178 height=15 valign=top style='width:133.2pt;border:none;
border-top:solid windowtext 1.5pt;padding:0cm 3.5pt 0cm 3.5pt;height:11.25pt'>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>Tel <b><span
style='font-weight:bold'>013-22 24 97<o:p></o:p></span></b></span></font></p>
</td>
</tr>
<tr>
<td width=179 valign=top style='width:134.6pt;border:solid silver 1.0pt;
border-bottom:none;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'>Leveransadress:<o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=176 valign=top style='width:132.2pt;border-top:solid silver 1.0pt;
border-left:none;border-bottom:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'>Faktureringsadress:<o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=178 valign=top style='width:133.2pt;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'>FAX: +46 13 10 19 02<o:p></o:p></span></font></p>
</td>
</tr>
<tr>
<td width=179 valign=top style='width:134.6pt;border-top:none;border-left:
solid silver 1.0pt;border-bottom:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'>Linköpings Universitet<o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=176 valign=top style='width:132.2pt;border:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'>Linköpings Universitet<o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span lang=EN-GB style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=178 valign=top style='width:133.2pt;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><b><font size=2
face="Times New Roman"><span style='font-size:10.0pt;font-weight:bold'><a
href="mailto:bengt.ragnemalm@imt.liu.se"><span lang=EN-GB>bengt.ragnemalm@imt.liu.se</span></a></span></font></b><b><font
size=2><span lang=EN-GB style='font-size:10.0pt;font-weight:bold'><o:p></o:p></span></font></b></p>
</td>
</tr>
<tr>
<td width=179 valign=top style='width:134.6pt;border-top:none;border-left:
solid silver 1.0pt;border-bottom:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'>Inst. för Medicinsk
Teknik</span></font><font size=2><span lang=EN-GB style='font-size:10.0pt'><o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span lang=EN-GB style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=176 valign=top style='width:132.2pt;border:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'>Faktura support<o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span lang=EN-GB style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=178 valign=top style='width:133.2pt;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span lang=EN-GB style='font-size:10.0pt'><a
href="http://www.imt.liu.se/"><font color=purple><span style='color:purple'>http://www.imt.liu.se</span></font></a><o:p></o:p></span></font></p>
</td>
</tr>
<tr>
<td width=179 valign=top style='width:134.6pt;border-top:none;border-left:
solid silver 1.0pt;border-bottom:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span lang=EN-GB style='font-size:10.0pt'>S-581 85
Linköping <st1:place w:st="on"><st1:country-region w:st="on">SWEDEN</st1:country-region></st1:place><o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span lang=EN-GB style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=176 valign=top style='width:132.2pt;border-top:none;border-left:
none;border-bottom:solid silver 1.0pt;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span lang=EN-GB style='font-size:10.0pt'>581 83
Linköping<o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span lang=EN-GB style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=178 valign=top style='width:133.2pt;padding:0cm 5.4pt 0cm 5.4pt'>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
</tr>
<tr>
<td width=179 valign=top style='width:134.6pt;border:solid silver 1.0pt;
border-top:none;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=176 valign=top style='width:132.2pt;border-top:none;border-left:
none;border-bottom:solid silver 1.0pt;border-right:solid silver 1.0pt;
padding:0cm 5.4pt 0cm 5.4pt'>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>Ref
1700 <st1:PersonName ProductID="Bengt Ragnemalm" w:st="on">Bengt Ragnemalm</st1:PersonName><br>
Märk med vårt Beställningsnr<o:p></o:p></span></font></p>
</td>
<td width=16 valign=top style='width:11.8pt;border:none;padding:0cm 5.4pt 0cm 5.4pt'>
<p style='margin:0cm;margin-bottom:.0001pt'><font size=2
face="Times New Roman"><span style='font-size:10.0pt'><o:p> </o:p></span></font></p>
</td>
<td width=178 style='width:133.2pt;padding:0cm 5.4pt 0cm 5.4pt'>
<p class=MsoNormal><i><font size=1 face="Times New Roman"><span
style='font-size:8.0pt;font-style:italic'>Vi kan göra mer än du kan drömma om
men för det omöjliga behöver vi en liten leveranstid.</span></font></i><font
size=2><span style='font-size:10.0pt'><o:p></o:p></span></font></p>
</td>
</tr>
</table>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
</body>
</html>