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zzdz2 · 2012-10-11

Posted on October 11, 2012 at 10:00ST Cortex-M3 programming manual nicely describes all instruction, how they work and what they do but there is no info how many clock cycles it takes to execute given instruction.Fortunately I found ARM Cortex-M3 ma...

zzdz2 · 2015-01-18

Posted on January 18, 2015 at 18:08It's compiler specific, some compilers can have an option to enable loop alignment.But generally, using CPU to generate pulses with single cycle accuracy is tricky.You can try timers to avoid such problems with CPU...

zzdz2 · 2014-12-11

Posted on December 12, 2014 at 08:39Do you have any global variables?I you have local vars, these are allocated on the stack and compiler doesn't warn about stack overrun.If possible try to use global data instead of local data on the stack.

zzdz2 · 2014-11-27

Posted on November 27, 2014 at 19:06I think the most feasible way to do the alignment is to put two NOP asm instructions before the gpio output block. It may work.I guess I was just lucky when I did the test and I got aligned instructions by chance.

zzdz2 · 2014-11-20

Posted on November 20, 2014 at 09:56I don't know, it should be single cycle.Maybe it's about flash read time.The code in your assembly listing is not aligned to 32-bit/4-byte address so it would need two reads per instruction.It's quite possible it ...

zzdz2 · 2014-11-19

Posted on November 19, 2014 at 17:27Hi,Yes, it looks like the CPU clock is set to 2MHz.Can you see the resulting assembly code from your compiler, maybe it would explain something here.I did some similar tests but with different compiler, if I remem...

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