Re: Help for init value of SRAM in MPC 562
"Geoff Field" <[email protected]> Wed, 02 Jul 2008 23:11:13 -0000
| Newsgroups | gmane.comp.hardware.motorola.microcontrollers |
|---|---|
| Message-ID | <[email protected]> |
--fKHPTC2aX7q9hCEI-yGGoKoxWCW9IzYTDomGLOK Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi Sudhersan, I'm not working with MPC500-series chips at the moment, but the usual approach is to declare/use a "non-init" segment. Most compilers will generate startup code that initialises all RAM apart from the non-init segment. I'm not sure of the details for doing this on your specific platform (compiler, in particular). However, your compiler manual should contain something on the subject. As an alternative, you could tweak the startup code itself to skip a certain location(s). Not recommended, but often done. Geoff --- In [email protected], Sudhersan Lal <sudhersanl@...> wrote: > > Hello Everyone=20 > Anybody know or can help me to find out more information regarding the initialization value of SRAM contents during power up .=20 > I would like to save some values in sram so that I can read that back after a reset , for eg saving a byte value and its compliment=20 and check the consistency between these two variables . This would make sure that, the value is really what I saved prior to reset and not the garbage value which would appear in the memory after a power up.=20 > Any existing behavior known for mpc microcontrollers related to this?=20 > if it is stored like the value and its compliment , what is the probability of the random initial values in two bytes to be compliment of each other and mistaken as the good value=20=20=20=20 > Regards > Sudhersan=20 --fKHPTC2aX7q9hCEI-yGGoKoxWCW9IzYTDomGLOK Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> </head> <body style="background-color: #ffffff;"> <!--~-|**|PrettyHtmlStartT|**|-~--> <div id="ygrp-mlmsg" style="width:655px; position:relative;"> <div id="ygrp-msg" style="width: 470px; margin:0; padding:0 25px 0 0; float:left; z-index:1;"> <!--~-|**|PrettyHtmlEndT|**|-~--> <div id="ygrp-text"> <p>Hi Sudhersan,<br> <br> I'm not working with MPC500-series chips at the moment, but the usual<br> approach is to declare/use a "non-init" segment. Most compilers will<br> generate startup code that initialises all RAM apart from the non-init<br> segment.<br> <br> I'm not sure of the details for doing this on your specific platform<br> (compiler, in particular). However, your compiler manual should<br> contain something on the subject.<br> <br> As an alternative, you could tweak the startup code itself to skip a<br> certain location(s). Not recommended, but often done.<br> <br> Geoff<br> <br> --- In <a href="mailto:MPC500%40yahoogroups.com">MPC500@yahoogroups.<wbr>com</a>, Sudhersan Lal <sudhersanl@<wbr>...> wrote:<br> ><br> > Hello Everyone <br> > Anybody know or can help me to find out more information regarding<br> the initialization value of SRAM contents during power up . <br> > I would like to save some values in sram so that I can read that<br> back after a reset , for eg saving a byte value and its compliment <br> and check the consistency between these two variables . This would<br> make sure that, the value is really what I saved prior to reset and<br> not the garbage value which would appear in the memory after a power up. <br> > Any existing behavior known for mpc microcontrollers related to this? <br> > if it is stored like the value and its compliment , what is the<br> probability of the random initial values in two bytes to be compliment<br> of each other and mistaken as the good value <br> > Regards<br> > Sudhersan <br> <br> </p> </div> <!--~-|**|PrettyHtmlStart|**|-~--> <span width="1" style="color: white;">__._,_.___</span> <!-- Start the section with Message In topic --> <div id="ygrp-actbar"> <span class="left"> <a href="http://groups.yahoo.com/group/MPC500/message/3943;_ylc=X3oDMTM0Z2RzZnVqBF9TAzk3MzU5NzE0BGdycElkAzYyNzYzODcEZ3Jwc3BJZAMxNzA2NTU0MjA1BG1zZ0lkAzM5NDgEc2VjA2Z0cgRzbGsDdnRwYwRzdGltZQMxMjE1MDQwMjc1BHRwY0lkAzM5NDM-"> Messages in this topic </a> (<span class="bld">5</span>) </span> <a href="http://groups.yahoo.com/group/MPC500/post;_ylc=X3oDMTJwazNkc3VjBF9TAzk3MzU5NzE0BGdycElkAzYyNzYzODcEZ3Jwc3BJZAMxNzA2NTU0MjA1BG1zZ0lkAzM5NDgEc2VjA2Z0cgRzbGsDcnBseQRzdGltZQMxMjE1MDQwMjc1?act=reply&messageNum=3948"> <span class="bld"> Reply </span> (via web post) </a> | <a href="http://groups.yahoo.com/group/MPC500/post;_ylc=X3oDMTJlMDFmcnZhBF9TAzk3MzU5NzE0BGdycElkAzYyNzYzODcEZ3Jwc3BJZAMxNzA2NTU0MjA1BHNlYwNmdHIEc2xrA250cGMEc3RpbWUDMTIxNTA0MDI3NQ--" class="bld"> Start a new topic </a> </div> <!------- Start Nav Bar ------> <!-- |**|begin egp html banner|**| --> <div id="ygrp-vitnav"> <a href="http://groups.yahoo.com/group/MPC500/messages;_ylc=X3oDMTJlZGNodGpxBF9TAzk3MzU5NzE0BGdycElkAzYyNzYzODcEZ3Jwc3BJZAMxNzA2NTU0MjA1BHNlYwNmdHIEc2xrA21zZ3MEc3RpbWUDMTIxNTA0MDI3NQ--">Messages</a> | <a href="http://groups.yahoo.com/group/MPC500/links;_ylc=X3oDMTJmdGlqcWdkBF9TAzk3MzU5NzE0BGdycElkAzYyNzYzODcEZ3Jwc3BJZAMxNzA2NTU0MjA1BHNlYwNmdHIEc2xrA2xpbmtzBHN0aW1lAzEyMTUwNDAyNzU-">Links</a> </div> <!-- |**|end egp html banner|**| --> <div id="ygrp-grft"> </div> <div id="ygrp-mkp"> <div id="hd">MARKETPLACE</div> <div id="ads"> <div class="ad"> <hr size=1 noshade><a href="http://us.ard.yahoo.com/SIG=13rjkuuc8/M=624381.12730922.13032918.10835568/D=groups/S=1706554205:MKP1/Y=YAHOO/EXP=1215047476/L=/B=oUzfBULaX9s-/J=1215040276370694/A=5396680/R=0/SIG=14e7adlkt/*http://media.adrevolver.com/adrevolver/href?banner=197791&place=26143&url_=http://tc.deals.yahoo.com/tc/blockbuster/display.com?cid=bbi00027 "> Special offer for Yahoo! 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