LeafLabs Garden » Topic: ARM acronyms somewhere

LeafLabs Garden » Topic: ARM acronyms somewhere http://forums.leaflabs.com/topic.php?id=99 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:09:23 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://forums.leaflabs.com/search.php Feyr on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-604 Thu, 22 Jul 2010 23:49:36 +0000 Feyr 604@http://forums.leaflabs.com/ i honestly haven't looked at intregrating it to wirish yet. i barely looked at the timers branch. that will probably take a while as my C is seriously rusty there's a couple limitation with my current code -in my case, since the dynamic range is so high the timer roll over and i don't think i can merge two timers to make a 32 bit (because the SMC is already used). this might need to be addressed in an interrupt.i haven't looked at implementing those yet - CCR1 and CCR2 seem to be swapped from what the ref manual say they should be. so it might not be measuring exactly what i think it's measuring (i sense more scope debugging this weekend ): CCR1 is the one moving in response to changes in distance, when it's CCR2 that should be -the code you commented on isn't the "working" version, for some reason github hasn't updated it yet. what's wrong with twiddling registers in a sketch? :) *mumbles something about 100 lines vimrc* bnewbold on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-603 Thu, 22 Jul 2010 23:09:19 +0000 bnewbold 603@http://forums.leaflabs.com/ Wow, super awesome! Great to see others twiddling register bits, especially from a sketch! Do you have any thoughts on how this functionality could be integrated with the new Timers library? (see <a href="http://leaflabs.com/docs/maple/timers/" rel="nofollow">http://leaflabs.com/docs/maple/timers/</a> ) Maybe something like Timer1.setChannel1Mode(TIMERS_PULSEIN); Timer1.readPulseMicros(); Timer1.readPulseMillis(); Feyr on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-602 Thu, 22 Jul 2010 22:27:03 +0000 Feyr 602@http://forums.leaflabs.com/ well, i am happy to announce that i have finally gotten the input capture to work. the offending line in the reference manual was this: Note: CC1S bits are writable only when the channel is OFF (CC1E = 0 in TIMx_CCER). and i wrongly assumed everything was OFF right after bootup. i will leave the code in github for future reference. now to package that in a useful way. refspec 5df13e743ee57150254998c8c7887afcb925662f Feyr on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-600 Thu, 22 Jul 2010 17:37:47 +0000 Feyr 600@http://forums.leaflabs.com/ hey perry, if you still plan on taking a look, i made a github repo to document my trials git://github.com/Feyr/PWM_Capture.git Feyr on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-573 Mon, 19 Jul 2010 06:53:58 +0000 Feyr 573@http://forums.leaflabs.com/ it's a pulse back from an ultrasonic sensor from seeedstudio (<a href="http://www.seeedstudio.com/depot/datasheet/Seeed%20Ultrasonic%20Sensor%20datasheet.pdf" rel="nofollow">http://www.seeedstudio.com/depot/datasheet/Seeed%20Ultrasonic%20Sensor%20datasheet.pdf</a>) basicly i need to emulate the pulseIn() from Wiring, but in a better way. later i might use the interrupt function but i'd settle for just getting it working for now to use the sensor, first i set the pin to output mode, send a 10us pulse and then switch back to input to read the distance as the pulse width my code looks like this so far, it's not very friendly but it makes for easy(er) tweaking: rcc_enable_clk_timer2(); Timer* timer2= (Timer*)TIMER2_BASE; timer2->CR2 = BIT(7) ; // set CCMR1 CC1S to 01 (set active input TI1) /// 01: CC1 channel is configured as input, IC1 is mapped on TI1. timer2->CCMR1 &= ~BIT(1); timer2->CCMR1 |= BIT(0); // set CCMR1 CC2S to 10 (set active input TI1) /// 10: CC2 channel is configured as input, IC2 is mapped on TI1 timer2->CCMR1 |= BIT(9); timer2->CCMR1 &= ~BIT(8); // select the active polarity on TI1FP1. write CC1P to 0 (active on rising edge) ///0: non-inverted: capture is done on a rising edge of IC1. timer2->CCER &= ~BIT(5); // select the active polarity on TI1FP2. write CC2P to 1 (active on falling edge) ///1: inverted: capture is done on a falling edge of IC1 timer2->CCER |= BIT(1) ; //select valid trigger input: write TS to 101 in SMCR (Slave Mode Config Register). meaning we should reset when TI1 triggers /// 101: Filtered Timer Input 1 (TI1FP1) timer2->SMCR |= BIT(6) | BIT(4) ; timer2->SMCR &= ~BIT(5); // write SMS to 100 in SMCR: slave controller in reset mode ///100: Reset Mode - Rising edge of the selected trigger input (TRGI) reinitializes the counter and generates an update of the registers timer2->SMCR &= ~BIT(1) ; //timer2->SMCR &= ~BIT(0); timer2->SMCR |= BIT(0); timer2->SMCR |= BIT(2); timer2->CR1|=BIT(9)&BIT(8); // enable the CC channels timer2->CCER |= (BIT0 | BIT4); // send a pulse pinMode(pingPin, OUTPUT); digitalWrite(pingPin, LOW); // ensure it is pulled low delayMicroseconds(2); digitalWrite(pingPin, HIGH); delayMicroseconds(10); digitalWrite(pingPin, LOW); delayMicroseconds(2); pinMode(pingPin, INPUT); // wait 40 ms, spec say the pulse will never be wider than 35ms if there are no obstacle within 4meters delay(40); //// after that we should in theory have the period and duty cycle in timer2->CCR1 and timer2->CCR2. i tried various things over the weekend: enabling the counter and tweaking registers but as bnewbold said, i'm probably missing an initialisation somewhere perry on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-569 Sun, 18 Jul 2010 22:50:51 +0000 perry 569@http://forums.leaflabs.com/ hi feyr, what sort of input signal are you trying to measure and what features do you need? i haven't played with the input capture at all but i can take a look and see if i can play with them a bit this weekend. bnewbold on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-565 Sat, 17 Jul 2010 13:18:05 +0000 bnewbold 565@http://forums.leaflabs.com/ I just re-pushed the i2c branch, not sure how it got deleted from github. I rebased it to master recently but didn't test after that so YMMV Feyr on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-564 Fri, 16 Jul 2010 16:52:12 +0000 Feyr 564@http://forums.leaflabs.com/ hah great thanks! i found some of what i was looking for this morning, and this should help fill the gaps. i'll try to take some notes and submit some code once i get it working one more thing, the doc (<a href="http://leaflabs.com/docs/maple/i2c/" rel="nofollow">http://leaflabs.com/docs/maple/i2c/</a>) refers to an "i2c" branch on github for libmaple but it doesn't seem to have been pushed. is it completly broken or just an oversight? bnewbold on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-562 Fri, 16 Jul 2010 13:06:36 +0000 bnewbold 562@http://forums.leaflabs.com/ Hi Feyr! Welcome to the joys of STM32 reference documentation! The register names (like CCER) are pretty confusing; they aren't "real" acronyms, just short variable names. I usually open a couple copies of that giant PDF and search the table of contents to look up register names. Eg, CCER is probably <pre> 13.4.9 TIM1&TIM8 capture/compare enable register (TIMx_CCER) . . . . . . . 311 </pre> If you find a better solution i'd love to hear it! Writing all this us would be a great project, if I had another day a week i'd spend it filling in bildr.org with this sort of information. I'm just wrapping up the basic timer implementation and i'm guessing that the advanced timer input stuff will be non-trivial. In the end it probably isn't too complicated, but the reference documentation takes a very, very long time to process, as there isn't always a summary of how registers should be configured to accomplish a given task, so you don't know if you're missing some peripheral configuration step until it all works. Using a timer instead of SysTick is probably the way to go; the basic timers have PWM input functionality, so i'd recommend using Timer4 instead of Timer1 (advanced) as it has fewer conflicts with other peripherals. The ./notes/pin-mapping.txt file in libmaple has a table of Maple-header to STM32-pin plus functionality; this really needs to get integrated into the docs! Geeze! <a href="http://github.com/leaflabs/libmaple/blob/master/notes/pin-mapping.txt" rel="nofollow">http://github.com/leaflabs/libmaple/blob/master/notes/pin-mapping.txt</a> You might also find these rough notes on the timer interrupts useful as general context: <a href="http://github.com/leaflabs/libmaple/blob/timers/notes/timers.txt" rel="nofollow">http://github.com/leaflabs/libmaple/blob/timers/notes/timers.txt</a> I believe TIM1_CH1N is the negative of TIM1_CH1? Page 340/1003 of the reference manual has a summary of what needs to be done. I recommend hacking these steps into a new function in ./libmaple/timers.c to work out all the kinks, then rewriting everything more cleanly once you understand it. If you send me code for a working PWM implementation i'd love to integrate it as a feature into libmaple; having working code in hand that can be disassembled and tested against is 90% of the battle! We're glad to hear you're digging in and would like to help as much as possible; post more questions! Feyr on "ARM acronyms somewhere" http://forums.leaflabs.com/topic.php?id=99#post-560 Thu, 15 Jul 2010 22:45:34 +0000 Feyr 560@http://forums.leaflabs.com/ Hello! i'm rather new to ARMs chip and wondering if someone has some links to solve my problems. first off, is there a list of the acronyms definitions somewhere? i'm reading the stm32 reference manual and not much of it make sense to me. ie, what's a TI1 or a TI1FP? or a CCER? maybe it's in a manual somewhere, but i haven't found it. to get down and dirty, im trying to use the PWM Input mode of the advanced timers to get the pulse width from an ultrasonic sensor. i tried messing with the systick timer (not precise enough or im being completly brain dead): the counter seem to wrap just from the overhead of reading the memory address. i haven't found much informations about pwm input, much less for the leaf. from reading the ref manual i'm under the impression i have to be on a few very specific gpio pins, is that right? something like TIM1_CH1N (what's the N for?), which is also called PA6 and pin 22. is there a reference somewhere that describe which gpio pin that maps to on the leaf? or is that a case of RTFS (read the ... schematic)? sorry for the dumb questions and imprecisions