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2005-03-24 by Lowry, Jeff
Code running from internal RAM seems to run about 4x faster than running from internal Flash. Is this true or do I have some settings wrong? Anybody know where I can find fetch timings for Ram vs Flash code execution? Thanks, Jeff.
2005-03-24 by Marko Pavlin (home)
Runing from RAM runs at Cclk. Flash has 60ns access time, which is 3x slower at 60MHz. Are you using MAM? Lowry, Jeff wrote:
> Code running from internal RAM seems to run about 4x faster than running > from internal Flash. Is this true or do I have some settings wrong? > Anybody know where I can find fetch timings for Ram vs Flash code > execution? Thanks, Jeff.
2005-03-24 by k b shah (lascaux)
It is a fact that the access from internal flash is slower then internal RAM, that is the reasn they have MAM setting.... it actually caches the instructions and execute from the cache, which results in faster execution. there are three different settings .. MAM -- off --- slowest MAM -- partially on -- Execution time more predictable MAM -- full on... best executin time. kb
----- Original Message -----
From: Marko Pavlin (home)
To: lpc2000@yahoogroups.com
Sent: Thursday, March 24, 2005 12:49 PM
Subject: Re: [lpc2000] LPC2138: Ram vs Flash code execution
Runing from RAM runs at Cclk. Flash has 60ns access time, which is 3x
slower at 60MHz. Are you using MAM?
Lowry, Jeff wrote:
> Code running from internal RAM seems to run about 4x faster than running
> from internal Flash. Is this true or do I have some settings wrong?
> Anybody know where I can find fetch timings for Ram vs Flash code
> execution? Thanks, Jeff.
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[Non-text portions of this message have been removed]2005-03-24 by Gus
(I could be wrong it has been a while) The chip defaults to 7 wait states for every flash access. The internal flash can run at 3 waitstates. This will make things faster. Also enable the MAM Double check the datasheet Gus --- In lpc2000@yahoogroups.com, "Lowry, Jeff" <jlowry@s...> wrote: > Code running from internal RAM seems to run about 4x faster than running
> from internal Flash. Is this true or do I have some settings wrong? > Anybody know where I can find fetch timings for Ram vs Flash code > execution? Thanks, Jeff.
2005-03-24 by Lowry, Jeff
Thanks. Now the same speed for Ram and Flash. Here's what I did: Benchmark: 5 byte memcpy from flash to ram. 12MHz osc, PLL disabled (cclk 12MHz), VPB=0 (1/4 cclk), MAM disabled: 30us. 12MHz osc, PLL disabled (cclk 12MHz), VPB=0 (1/4 cclk), MAM fully enabled with 1 fetch cycle: 7.5us. I'll have to see how much of a hit I took on the current draw. Jeff.
-----Original Message----- From: k b shah (lascaux) [mailto:kbshah@...] Sent: Thursday, March 24, 2005 10:22 AM To: lpc2000@yahoogroups.com Subject: Re: [lpc2000] LPC2138: Ram vs Flash code execution It is a fact that the access from internal flash is slower then internal RAM, that is the reasn they have MAM setting.... it actually caches the instructions and execute from the cache, which results in faster execution. there are three different settings .. MAM -- off --- slowest MAM -- partially on -- Execution time more predictable MAM -- full on... best executin time. kb ----- Original Message ----- From: Marko Pavlin (home) To: lpc2000@yahoogroups.com Sent: Thursday, March 24, 2005 12:49 PM Subject: Re: [lpc2000] LPC2138: Ram vs Flash code execution Runing from RAM runs at Cclk. Flash has 60ns access time, which is 3x slower at 60MHz. Are you using MAM? Lowry, Jeff wrote: > Code running from internal RAM seems to run about 4x faster than running > from internal Flash. Is this true or do I have some settings wrong? > Anybody know where I can find fetch timings for Ram vs Flash code > execution? Thanks, Jeff. Yahoo! Groups Sponsor ADVERTISEMENT ------------------------------------------------------------------------ ------ Yahoo! Groups Links a.. To visit your group on the web, go to: http://groups.yahoo.com/group/lpc2000/ b.. To unsubscribe from this group, send an email to: lpc2000-unsubscribe@yahoogroups.com c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. [Non-text portions of this message have been removed] Yahoo! Groups Sponsor ADVERTISEMENT click here <http://us.ard.yahoo.com/SIG=12930d5s6/M=298184.6191685.7192823.3001176/ D=groups/S=1706554205:HM/EXP=1111774715/A=2593423/R=0/SIG=11el9gslf/*htt p://www.netflix.com/Default?mqso=60190075> <http://us.adserver.yahoo.com/l?M=298184.6191685.7192823.3001176/D=group s/S=:HM/A=2593423/rand=916463166> ________________________________ Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/lpc2000/ * To unsubscribe from this group, send an email to: lpc2000-unsubscribe@yahoogroups.com <mailto:lpc2000-unsubscribe@yahoogroups.com?subject=Unsubscribe> * Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> . [Non-text portions of this message have been removed]