LeafLabs Garden » Topic: Test data received by interruption

LeafLabs Garden » Topic: Test data received by interruption http://forums.leaflabs.com/topic.php?id=9529 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:20:36 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://forums.leaflabs.com/search.php Bernardo769 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529&page=2#post-21116 Fri, 16 Nov 2012 15:52:27 +0000 Bernardo769 21116@http://forums.leaflabs.com/ Hi, I used a second Maple with this sketch : <pre><code>#include <Servo.h> #define PoloDigi4 26 Servo myservo; void setup(){ pinMode(BOARD_LED_PIN, OUTPUT); // Servo : myservo.attach(PoloDigi4); } // Move the servo to one extreme then to the other void loop(){ togglePin(BOARD_LED_PIN); for (int valServo=1000; valServo<2000; valServo++){ myservo.writeMicroseconds(valServo); // OK delay(1); } togglePin(BOARD_LED_PIN); for (int valServo=2000; valServo>1000; valServo--){ myservo.writeMicroseconds(valServo); // OK delay(1); } }</code></pre> With a connection between Maple1-pin20 to Maple2-pin26 I still have the problem : <a href="http://bernard.o.perso.neuf.fr/Electronic/MAPLE/BugRC/sourceMaplePWM.jpg" rel="nofollow">http://bernard.o.perso.neuf.fr/Electronic/MAPLE/BugRC/sourceMaplePWM.jpg</a> If there is no other solution, I'll put up a soft filter to eliminate and correct the incorrect values. gbulmer on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529&page=2#post-21054 Wed, 14 Nov 2012 15:02:02 +0000 gbulmer 21054@http://forums.leaflabs.com/ Bernardo769 - You can use a second Maple, but you don't need a second Maple. Take a PWM output pin, and connect it back into the pin you are trying to test. The timers are pure hardware, so once the values for frequency and 'pwmWrite' ratio are set, they don't generate interrupts, or run any software. Bernardo769 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529&page=2#post-21053 Wed, 14 Nov 2012 13:13:52 +0000 Bernardo769 21053@http://forums.leaflabs.com/ My lack of experience forces me to ask the obvious questions for you. I'll use a second Maple to generate a PWM signal clean. I will keep you informed of the outcome. gbulmer on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529&page=2#post-21043 Tue, 13 Nov 2012 16:14:23 +0000 gbulmer 21043@http://forums.leaflabs.com/ Bernardo769 - what are you asking? I am not clear. A simple technique to generate consistently timed events, potentially useful to test interrupts, is to use a signal from a timer. Once set, the timer will be relatively stable (using the MCU's crystal), and consistent. A very simple approach, which needs very little software is feed a timers PWM output into a pin, and that gives a signal source which can trigger an interrupt. By adjusting the duration of the timer count, you can sweep it across a range of frequencies in 1/72,000,000 increments. By using two timer outputs from the same timer, you can trigger two pins, and by adjusting the PWM value for each, you can set which pin changes first and second. Bernardo769 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529&page=2#post-21041 Tue, 13 Nov 2012 15:26:29 +0000 Bernardo769 21041@http://forums.leaflabs.com/ If you have specific tests, I can do it, even if I do not control everything... gbulmer on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-21040 Tue, 13 Nov 2012 14:27:40 +0000 gbulmer 21040@http://forums.leaflabs.com/ ala42 - I think it is possible for SysTick to fire after the calculation of millis in <code>while (ms != millis());</code>, but before <code>if(systick_check_underflow())</code> gets to check the value, so it is just possible that this will also give the wrong value very occasionally. AFAIK, SysTick priority can be changed, though I have never tried to do that. So it might be simpler to raise the SysTick priority above the interrupt service routine; simpler in the sense that micros() and millis() would work without extra checking. Bernardo769 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-21012 Mon, 12 Nov 2012 13:26:15 +0000 Bernardo769 21012@http://forums.leaflabs.com/ Despite all the proposed changes, I still worry. In summary of the changes: Sketch : <pre><code>#include "voieRC.h" #include <Servo.h> #include "nvic.h" #define Serial SerialUSB #define pinVoieGAZ 20 voieRC voieGAZ(pinVoieGAZ); #define PoloDigi4 26 Servo myservo; void setup() { attachInterrupt(pinVoieGAZ, interruptRC_GAZ, CHANGE); // Servo : myservo.attach(PoloDigi4); } void loop() { //SerialUSB.println(voieGAZ.valeur()); myservo.writeMicroseconds(constrain(voieGAZ.valeur(), SERVO_DEFAULT_MIN_PW, SERVO_DEFAULT_MAX_PW)); // OK //delay(50); } void interruptRC_GAZ(void) { voieGAZ.etat(); } void voieRC::etat() { //noInterrupts(); if (digitalRead(this->pinRC) == HIGH) { // Front montant timeUP = micros(); timeDOWN = timeUP; } else { // Front descendant timeDOWN = micros(); lastValidValue = timeDOWN - timeUP; } //interrupts(); }</code></pre> wirish_time.h : <pre><code>static inline uint32 micros(void) { uint32 ms; uint32 cycle_cnt; uint32 res; do { ms = millis(); cycle_cnt = systick_get_count(); } while (ms != millis()); if(systick_check_underflow()) { ms++; cycle_cnt = systick_get_count(); } /* 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> All ideas are property came... ala42 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-21001 Mon, 12 Nov 2012 06:15:49 +0000 ala42 21001@http://forums.leaflabs.com/ The systick IRQ has a low prio, lower that your IRQ handler, so the milli seconds counter is not updated, when the overflow occurs in your IRQ handler. Add #include "nvic.h" and use this micros function: <pre><code>static inline uint32 micros(void) { uint32 ms; uint32 cycle_cnt; uint32 res; do { ms = millis(); cycle_cnt = systick_get_count(); } while (ms != millis()); if(systick_check_underflow()) { ms++; cycle_cnt = systick_get_count(); } /* 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> Bernardo769 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-20985 Mon, 12 Nov 2012 00:37:43 +0000 Bernardo769 20985@http://forums.leaflabs.com/ good idea. I renamed the file wirish_time.h in wirish_time.h.new to compile, I get the message : fatal error: wirish_time.h: No such file or directory The change is well used. <pre><code>/** * Returns time (in microseconds) since the beginning of program * execution. On overflow, restarts at 0. * @see millis() */ static inline uint32 micros(void) { uint32 ms; uint32 cycle_cnt; uint32 res; do { ms = millis(); cycle_cnt = systick_get_count(); } 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> gbulmer on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-20977 Sun, 11 Nov 2012 17:04:41 +0000 gbulmer 20977@http://forums.leaflabs.com/ Bernardo769 - Good question. How about change the name of the file from wirish_time.h to xxx..xxx and see if your program compiles? Bernardo769 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-20976 Sun, 11 Nov 2012 15:47:12 +0000 Bernardo769 20976@http://forums.leaflabs.com/ I still have the problem I found the file wirish_time.h in the directory C:\Program Files\maple-ide-0.0.12-windowsxp32\hardware\leaflabs\cores\maple When I look in the directory where the compilation is C:\Users\Olivier\AppData\Local\Temp\build7029581827160573567.tmp, how to verify that the change is taken into account gbulmer on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-20973 Sun, 11 Nov 2012 14:00:06 +0000 gbulmer 20973@http://forums.leaflabs.com/ Bernardo769 - can you find the file wirish_time.h? On my Mac, the path is MapleIDE.app/Contents/Resources/Java/hardware/leaflabs/cores/maple/ so it is likely something similar on other platforms. Copy wirish_time.h to wirish_time.h.old (just in case you make a mistake) Edit the file wirish_time.h, and replace <pre><code>do { cycle_cnt = systick_get_count(); ms = millis(); } while (ms != millis());</code></pre> with <pre><code>do { ms = millis(); cycle_cnt = systick_get_count(); } while (ms != millis());</code></pre> Unfortunately, the whole directory structure has changed, so it might be awkward to navigate. Bernardo769 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-20971 Sun, 11 Nov 2012 13:21:16 +0000 Bernardo769 20971@http://forums.leaflabs.com/ Thank you for the information. I downloaded the file libmaple-master.zip I'm not used to these manipulations. How to install its contents. I would not do anything stupid. gbulmer on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-20970 Sun, 11 Nov 2012 12:49:39 +0000 gbulmer 20970@http://forums.leaflabs.com/ bubulindo - that version of micros() contains a bug. See <a href="http://forums.leaflabs.com/topic.php?id=1098" rel="nofollow">http://forums.leaflabs.com/topic.php?id=1098</a> <pre><code>do { cycle_cnt = systick_get_count(); ms = millis(); } while (ms != millis());</code></pre> should be <pre><code>do { ms = millis(); cycle_cnt = systick_get_count(); } while (ms != millis());</code></pre> Sadly LeafLabs haven't updated the IDE download in the last year, so you need to patch it yourself, or go to github <a href="https://github.com/leaflabs/libmaple" rel="nofollow">https://github.com/leaflabs/libmaple</a> That bug is enough to cause the value returned by micros() to jump backwards by almost 1000 microseconds, which might explain the results. I don't think it is accurate to say <blockquote>Because the systick timer doesn't count microseconds, this is, as far as I can see something like millis() * 1000. </blockquote> systick counts at 72MHz, and counts down from 71999, i.e. 1 milisecond. <code>(ms * US_PER_MS)</code> gives the number of complete milliseconds, measured in microseconds, the timer has been running. <code>(SYSTICK_RELOAD_VAL + 1 - cycle_cnt)</code> gives the number of clock cycles (72MHz) into the current millisecond <code>(SYSTICK_RELOAD_VAL + 1 - cycle_cnt) / CYCLES_PER_MICROSECOND</code> gives the number of microseconds into the current millisecond. So the calculation is yielding a microsecond resolution timer, but with a range much bigger than 1 millisecond. Bernardo769 on "Test data received by interruption" http://forums.leaflabs.com/topic.php?id=9529#post-20969 Sun, 11 Nov 2012 11:54:57 +0000 Bernardo769 20969@http://forums.leaflabs.com/ I have a handheld oscilloscope that gives me a correct signal to the output of the servo tester. The servo connected to the servo tester responds correctly. The output signal of servo tester is like this: <a href="http://robotpic.free.fr/tl_files/willy/images/servotime.gif" rel="nofollow">http://robotpic.free.fr/tl_files/willy/images/servotime.gif</a>