http://forums.leaflabs.com/topic.php?id=1958 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:15:48 +0000 http://bbpress.org/?v=1.0.2 q http://forums.leaflabs.com/search.php http://forums.leaflabs.com/topic.php?id=1958#post-11434 Wed, 27 Jun 2012 22:42:38 +0000 mbolivar 11434@http://forums.leaflabs.com/ <p>Thanks for making sure I didn't botch the fix forever ;) </p> http://forums.leaflabs.com/topic.php?id=1958#post-11427 Wed, 27 Jun 2012 18:16:37 +0000 ala42 11427@http://forums.leaflabs.com/ <p>Right. I caught the bug in the initial version and posted a fix, my fix was messed up when added to the libmaple code and I caught it again :) </p> http://forums.leaflabs.com/topic.php?id=1958#post-11423 Wed, 27 Jun 2012 12:56:51 +0000 mbolivar 11423@http://forums.leaflabs.com/ <p>Actually, looks like ala42 caught this in <a href="https://github.com/leaflabs/libmaple/commit/f7e384a5eaa1e1f9f6bf315a8860d9d61284edc3">f7e384a5</a>. This patch will be part of the next release. </p> http://forums.leaflabs.com/topic.php?id=1958#post-11398 Tue, 26 Jun 2012 22:31:04 +0000 mbolivar 11398@http://forums.leaflabs.com/ <p>Thanks for the report; will fix. </p> http://forums.leaflabs.com/topic.php?id=1958#post-11383 Tue, 26 Jun 2012 09:47:07 +0000 magnuskarlsson 11383@http://forums.leaflabs.com/ <p>The code in wirish_time.h for micros() has a bug - it sometimes return a value 1000 uS more than the actual microsecond count due to an unprotected systick overflow.</p> <p>Original code:</p> <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 = (fms * US_PER_MS) + (SYSTICK_RELOAD_VAL + 1 - cycle_cnt) / CYCLES_PER_MICROSECOND; return res; }</code></pre> <p>Fixed code:</p> <pre><code>static inline uint32 micros(void) { uint32 fms, lms; uint32 cycle_cnt; uint32 res; do { // make sure millis() return the same value before and after // getting the systick count fms = millis(); cycle_cnt = systick_get_count(); lms = millis(); } while (lms != fms); /* SYSTICK_RELOAD_VAL is 1 less than the number of cycles it actually takes to complete a SysTick reload */ res = (fms * US_PER_MS) + (SYSTICK_RELOAD_VAL + 1 - cycle_cnt) / CYCLES_PER_MICROSECOND; return res; }</code></pre>