http://forums.leaflabs.com/topic.php?id=1098 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:13:58 +0000 http://bbpress.org/?v=1.0.2 q http://forums.leaflabs.com/search.php http://forums.leaflabs.com/topic.php?id=1098#post-6923 Thu, 20 Oct 2011 22:06:27 +0000 mbolivar 6923@http://forums.leaflabs.com/ <p>looks like "someone" indeed made a stupid mistake. sorry about that; and thanks for the fix (again).</p> <p><a href="https://github.com/leaflabs/libmaple/commit/f7e384a5eaa1e1f9f6bf315a8860d9d61284edc3" rel="nofollow">https://github.com/leaflabs/libmaple/commit/f7e384a5eaa1e1f9f6bf315a8860d9d61284edc3</a> </p> http://forums.leaflabs.com/topic.php?id=1098#post-6803 Sun, 09 Oct 2011 20:32:48 +0000 ala42 6803@http://forums.leaflabs.com/ <p>Right, that is buggy. I ment it like I posted it at <a href="http://forums.leaflabs.com/topic.php?id=756#post-4462" rel="nofollow">http://forums.leaflabs.com/topic.php?id=756#post-4462</a>. Looks like someone did not cut&amp;paste my code, so the current version is buggy :( </p> http://forums.leaflabs.com/topic.php?id=1098#post-6793 Sat, 08 Oct 2011 20:09:59 +0000 gbulmer 6793@http://forums.leaflabs.com/ <p>To help a user, I ended up looking at the source of micros()<br /> <a href="http://forums.leaflabs.com/topic.php?id=1082&amp;page=2#post-6792" rel="nofollow">http://forums.leaflabs.com/topic.php?id=1082&amp;page=2#post-6792</a></p> <p>To save folks some time, here is the source of micros() again:<br /> <pre><code>static inline uint32 micros(void) { uint32 ms; uint32 cycle_cnt; uint32 res; do { cycle_cnt = systick_get_count(); ms = millis(); } while (ms != millis()); /* SYSTICK_RELOAD_VAL is 1 less than the number of cycles it actually takes to complete a SysTick reload */ res = (ms * US_PER_MS) + (SYSTICK_RELOAD_VAL + 1 - cycle_cnt) / CYCLES_PER_MICROSECOND; return res; }</code></pre> <p>I think there is a bug.<br /> I think<br /> <pre><code>do { cycle_cnt = systick_get_count(); ms = millis(); } while (ms != millis());</code></pre> <p>should be<br /> <pre><code>do { ms = millis(); cycle_cnt = systick_get_count(); } while (ms != millis());</code></pre> <p>I think the idea is to detect if systick has wrapped around, and hence incremented millis(), hence the second one would be right.<br /> What do you think? </p>