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    Could you help me?

    this is a wonderfully clear and concise analogy of nyquist sampling restrictions
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    TeensyPico- Miniaturization of Teensy 4.0 Board - 12x12mm Teensy board as QFN package

    yes- if you could put the cpu and the regulator on top (like the photo you have of the imaging chip on top) with its upper surface exposed that would help a lot. we did some thermal imaging of a Teensy 4.0 at 600 MHz and found that the top of the cpu and the top of the regulator were within 2...
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    TeensyPico- Miniaturization of Teensy 4.0 Board - 12x12mm Teensy board as QFN package

    2: How will power dissipation work? Running at 600 MHz, a Teensy 4.0 typically uses about 100 mA. Can this 12x12 mm package with another layer of insulating material really dissipate 0.5 watts? What is it's thermal resistance? (or how much additional temperature rise can be expected in the...
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    Teensy 4.1 Radio Interference Shielding?

    is the nosecone at least 6 inches or 12 inches tall? is it balsa wood? with some 0.125 od mini 50 ohm coax maybe you could bury a monopole w short drooping radials or a dipole in the nosecone. or put a thin dipole made from thick foil in the outside of the cone or body and hold it down with...
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    Teensy 4.1 Radio Interference Shielding?

    if you go with lora you can get 0.1 and 1 watt modules. your range may get better rather than suffer because at 300 baud receiver sensitivity is an astounding 0.01 uv which is 20-24 db better than many fsk radio rcvrs. as the baud rate goes up so will rcvr sens but is still a bit better at 19200...
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    Permanent ADC damage caused by running this code

    power monitor do you have any way of ac line power monitoring for dropouts and glitches? a) if you are having a line voltage drop out every 5-7 days and if your sig gen starts up with a nasty glitch when ac is restored (as opposed to turning it on) that might be the problem. you can test...
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    GPS reception blocked by RFI

    i have a drone w gps - very small antenna. outdoors lock 3-4+ sat usually takes 1-2 minits. indoors (tile roof) often takes 5-6 minits and as jonr says, once it has aquired, i can carry it inside no problem
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    Shooting chronograph using a teensy 4.0?

    a friend of mine used to produce and sell those 30-40 years ago. as i remember he used a pin diode optical sensor to detect a fast rising or falling edge as the bullet went over the traps. rising light from reflection of sun or sky off bullet or falling if shadow of bullet passed over sensor...
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    How Long Can Teensy 4.1 Run Continuously Without Breaking

    speaking of whisker growth - do your homework before your last cleaning of the board, some components of some cleansers/solvents that get left behind will actually accelerate whisker formation and i would also say do not spray on an anti-fungal coating - i have seen anti-fungal coatings that...
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    LC draws more current than 3.1 in Snooze modes, does not work on digital

    that hib current for tlc is way too high - should be a few ua there are several things that lower the hib current - most important is to set pin 17 or whichever is the "5v out" pin to be an output, then set it low.
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    Having problems with time it takes Snooze to wake up on digital pin

    i agree that it would be hard for that to cause 20ms. i also agree that 20ms is a long time - especially on T4 you may have to break down and write a super simple code that does nothing other than wait for digital pin to go low, wake and activate led for short time, and watch on your logic...
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    Having problems with time it takes Snooze to wake up on digital pin

    if (who== PIN_AX) { if (AuxHigh()) digitalWrite(13,HIGH); if you you change above to be digitalWrite(13,HIGH); leaving off the if auxhi does it help?
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    Having problems with time it takes Snooze to wake up on digital pin

    the logic anal display does not show that clear on my display. are you timing from when the aux pin goes on the rcvr or from when you begin or end the serial stream into the transmitter? which teensy?
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    Query speed limit teensy 4.1

    i think i remember seeing a post by Paul S a year or so ago discussing how NXP had a small register to control to trise tfall time for i/o pins (they had EMI reduction in mind) so software timing aside you might get crisper pulses if you set the trise/tfall to its fastest value.
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    LM324 op-amp output to Teensy 3.2 analog input reads 0.00. Meter shows 2.96v. Help?

    had overlooked on the schematic -non inverting input of lm324 at ground - will not work as desired that way. non inverting input would have to be at 1.65 or so volts for proper action. edit - is that a minus sign on the 3.3 v input to the amp? if so a gnd connection for the non inverting input...
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    LM324 op-amp output to Teensy 3.2 analog input reads 0.00. Meter shows 2.96v. Help?

    the lm324 has restricted input voltage common mode range - 1.7 v from +supply and 0v from -supply so if it is powered from 5v the inputs can go as high as 3.3 with no tolerance and no margin. the output swing is also limited. with 5v supply output swing high is 3.5 typ 3.3 min and output swing...
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    Backup Strategy?

    luni's advice to stock so as to bridge the gap is a good one, altho you have probably waited too long. i have been designing hardware since 1975 and in the old days you could actually avoid single source parts. then starting about 1977 and the spreading use of lsi the waters became murky. since...
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    Teensy4 PWM frequency modulation and overhead questions

    seems feasible to me - give it a go. i had similar doubts about using Teensy LC to produce nice pseudo sine waves at up to 2 khz for modulation of an RF carrier (rather than sq waves to reduce occupied spectrum) using the built in DAC, with each burst of cycles starting/ending at or very near...
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    Teensy 4: Global vs local variables speed of execution

    sometimes - i just last week had to remove one pole after an op amp and before adc input on t4 to get a 3-6 db improvement in signal to noise. the t4 seems to spit more charge out the adc input than the t3.6 (for which the filter had been designed originally), r was 1k, c was 0.0033u poly so...
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    Monitoring battery voltage with LC

    yes - i have aref tied to 3.3 and should have mentioned it and yes - that must be the default for reference because i never have used the adc_reference........ glad you are on the air - don't forget to play with sampling and conversion and averaging settings so you can get the speed vs accuracy...
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    Monitoring battery voltage with LC

    jonr - thanks for the feedback i got in a t4 code that is a spectrum analyzer, fed in a very clean 10 khz 3vp-p sinewave, and saw the same 2nd harmonic size with and without those lines - so in that exact case they were not driving distortion up but i am sure you have seen cases where they do...
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    Teensyduino 1.53 Released

    tested teensyduino with arduino 1.8.13 this am - all ok w compile/run/serial monitor using codes containing adc functions for tlc, t36, t4. install 153 on top of 153b3, win7pro64 do not know whether it is new arduino or teensyduino 1.53 (i noticed this with 153b3 also) but having the serial...
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    Monitoring battery voltage with LC

    here are excerpts from that code - even tho i did not need bandwidth i left conversion, sampling, and averaging as they had been for fast operation in a previous code because i am lazy - you will want to play with them and perhaps get a tiny bit of additional accuracy. #include <ADC.h>...
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    Monitoring battery voltage with LC

    design the divider for low current draw on the battery - in an almost identical situation where i needed to read batt v up to at least 14v (there was an ulta low iq regulator between batt and tlc) i used 2.2 meg batt to analog in and 470 k analog in to gnd so that the batt current drawn by the...
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    Teensyduino 1.53 Beta #3

    more on 1.8.13 maybe the guys at Arduino are ok after all - if you go into preferences and turn off "check for updates on start", get out of Arduino, shut down windows, reboot windows then that pesky message seems to go away - i hope forever. maybe previous versions did not not default that to...
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    Odd digitalread problem

    maybe not a miracle - Murphy never sleeps
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    Teensyduino 1.53 Beta #3

    thanks for the feedback that is right - arduino 1.8.13 - since there is only one adc library in the teensy stuff i wonder why it had to think so hard very annoying item 1.8.13 - the engineering computers here have never been nor ever will be connected to to the world - and arduino often puts a...
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    Teensyduino 1.53 Beta #3

    did closer inspection of compile reports re ADC under 1.53 beta 3 and found something that is not an error, not a warning, but i don't remember it from past releases. as per previous post TLC T36 T4 all compile and run fine. all have this little funny in the compile listing - i have no idea if...
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    Teensyduino 1.53 Beta #3

    compiles using ADC library worked ok TLC, T35, T4. (of course using the new settings syntax i had to do for 1.52) ala adc->adc0->setAveraging(1); etc have not timed any ADC yet
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    Teensyduino 1.53 Beta #3

    under win7pro64: uninstall arduino 1.8.5 (and teensyduino 1.52), install arduino 1.8.13, install teensyduino 1.53 beta 3, compiled and ran just fine several programs each for TLC, T36, T4. some TLC and T36 pgms date back 2-2.5 years, T4 from about time of intro. all compiles fine, all uploads...
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    Odd digitalread problem

    if your generator is 0 to 3.3 no load and 0 to 3.3 when hooked to teensy then current load is not a player. have you looked at the gen both before and after connection to teensy? also - just be be safe set gen to do 0.25 to 3.0 v so that even with some measurement error you are not driving the...
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    I think i destroyed my Teensy 4.0

    i would not say easy - depends on what kind of soldering/de-soldering tools you have. good news it only has six leads, bad news is it has a thermal pad center bottom that i bet is soldered down also. hopefully someone with more surface mount experience than i have can weigh in on that. but i...
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    I think i destroyed my Teensy 4.0

    that is the 3.3 v regulator how very hot but no current ? - it normally takes LOTS of current to get real hot i have a thermal image to send you - how did you attach that photo? never mind - i seem to have done it after all image is T4 at 816 MHz center of cpu and center 3.3 v regulator both...
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    Teensyduino 1.53 Beta #2

    i saw some syntax changes between TD 1.48 and 1.52 that may relate to 1.53 betas? needed in 1.48 adc->setAveraging(1,ADC_0); needed in 1.52 adc->adc0->setAveraging(1); also - total crash when trying to compile adc for TLC - see post #46 in "Teensyduino 1.52 released" in addition i posted it...
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    Teensy LC analog pins crosstalk

    oddson - i agree carlosemello - you used the word "piezo" - at a glance it might seem that you can just hook the output of a piezo sensor (high C high Z) to a mux/atod but that is problematic for several reasons including those already mentioned by Tommyburger and others. if your input sensors...
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    Teensy LC analog pins crosstalk

    is a8 a default analog in? i have only used a10 and a11 TLC and have used this declaration: const int readPin = A10; const int readPin2 = A11; and then this setup: pinMode(A10, INPUT); pinMode(A11, INPUT); adc->adc0->setAveraging(1); adc->adc0->setResolution(12)...
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    Teensy 4.0 power button and brown-out detection?

    jonr is right - but if you have a scope check for oscillation on the regulator output after you add the cap - many low drop out regulators are sensitive to Cl and the esr of Cl ala they become unstable. if you have the part number get the datasheet - they normally describe the envelope of...
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    Teensy ADC resolution

    i have never used a 3.2, have never used the a/d in the LC in a situation where i really cared about usable resolution, but with the 3.6 i have gotten a dynamic range of 70db which is equiv to 11.6 bits and with the 4.0 have gotten 77 db which is equiv to 12.8 bits. in both cases had tuned for...
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    Teensy 4.0 Low Power

    campbell - that is an interesting observation. in 1977 Motorola had a trademark term for their newest family of processors - "systems on silicon" - wrong. but things like the ridiculously complex mpus on T3.6 and T4 along with all of the core code PaulS and others wrote and all of the library...
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    Teensy 4.0 Low Power

    it it is any help, when i was testing T4 snooze i started with example code Duff had put in the Snooze library such as some thing like DeepSleep_all_wakeups - you might compare your code with that - i was using ARD 1.8.5,TD1.52 as i remember, as the lib is right now there are restrictions on...
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    please help w code to NOT initialize variables

    cleaned up redundant code, no longer needs code changes in isr2 depending on slow/fast task time, and the comments include editing one of the teensy core files so that the abort/recover time goes from 250 ms to 2.5 ms (much more practical). i have not had any usb or start-up glitches with the...
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    Is a decoupling capacitor necessary for 5v in on the Teensy 4.0?

    there is a 2.2 ufd on the T4 board on that pin - that is probably enough - leave room in your artwork for and external 10-22 ufd but you probably won't need it.
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    please help w code to NOT initialize variables

    when i sped it up to us=6250 and lg=625 the line in isr2() "++tc" had to be commented to prevent skipping one task on a restart - who knows, at even faster task intervals it might have to become --tc 6250 625 does a task ea 1/160 of a second or 1 time around all 8 tasks in 1/20 of a second
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    please help w code to NOT initialize variables

    as a final summary point here is the code for 8 timeslices/4 tasks using noinit. i am sure that a real C programmer could tighten it up and shrink it even further. in task2 either comment or un-comment the two lines hang:, goto hang; to see normal versus hung/long task performance // teensy...
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    please help w code to NOT initialize variables

    to add to that summary - the 4 task 8 timeslice (01020103) version using the noinit attribute method uses these TLC resources: pgm space 12%, ram space 26%, both pit timers, and the abort-recover dead time is 250 ms. defragster - i got the same results you did on the code you posted
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    please help w code to NOT initialize variables

    KurtE - have you run out of time for this? here instead of a code snippet is an entire pgm that boils it all down comes up tries to recover from maybe_saved - prints result,waits 5 seconds, re assigns values, does soft restart, and thus cycle continues. as shown it will run in that cycle over...
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    please help w code to NOT initialize variables

    KurtE - here is the top section of my pgm so you can see where i put your statements and also the compiler error listing - earlier in this thread you can see an eeprom solution that is the complete code. please do not laugh out loud if i bungled it badly. const int led = 13; // set time per...
  48. A

    please help w code to NOT initialize variables

    jonr - this version compiles no warnings and the contents of the variables it is used on do live thru the soft restart !!! - best solution so far - thank you KurtE - compiler not happy - after supper i will look at some more and maybe post compiler messages - thank you
  49. A

    please help w code to NOT initialize variables

    no dice - compiler comes back w "warning 'noinit' attribute directive ignored - it compiles and of course variables are all zero after restart - but thank you
  50. A

    please help w code to NOT initialize variables

    thanks - will try and let you know
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