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  1. Flying a drone with RC commands from a Teensy - anyone done this? Need help.

    There is a project with code that supplies RC control commands to drones from an NRF24L01 here:
    https://github.com/goebish/nrf24_multipro

    I want to be able to use a Teensy 4.1 to run it, but the...
  2. I picked this thread back up. The thread...

    I picked this thread back up. The thread referenced above is long. Can we confirm that basic communication is possible with the updated library? Is there a due date for an official version?
  3. Teensy 4.x > Teensy 4.x communication usion NRFL2401

    I need to implement communication between two Teensy 4.x boards using NRF24L01 units.

    I found the below thread for interfacing Arduino Megas and Teensy 4s, but I'm not sure if the code easily...
  4. Need overview on usage of Quadtimer features on Teensy 4

    Digital pins are either FlexPWM pins or Quadtimer pins. I have been making smart usage of the Flexpwm pins for executing PFM and signal edge feedback. However, I believe I have a task that is well...
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    Darn...looks like detecting the overflow and...

    Darn...looks like detecting the overflow and accounting for it is the only way.
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    Teensy4.0 CPU count reset

    Teensy 4 goes through it's full CPU count in about 7.15 seconds. I need to reference it in order to fix timing. However, there's a jump when ever the CPU flips. Is there a slower clock I can...
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    Ahhh, I see. Wonderful. Thank you!

    Ahhh, I see. Wonderful. Thank you!
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    Bad sentence. I have code for FALLING. I need...

    Bad sentence. I have code for FALLING. I need code for CHANGE and RISING configs individually, not in tandem.
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    Thanks again for this code. How can I modify it...

    Thanks again for this code. How can I modify it to get an interrupt on both edges and rising edges only?
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    Teensy4 ADC pin switching speed

    I need to collect ADC readings from more than two pins with a Teensy4.
    How fast should I expect to be able to reset which pin to take the ADC reading from and get a reliable reading?
  11. Need reliable 915mhz units compatible with Teensy4

    I've been using simple 433mhz units with my Teensy 4 and I see that I can only get bit rates of 10khz. I need bit rates of 40khz, and according to initial research, I may be able to get this with...
  12. Teensy4 with different analogWriteResolution settings on each pin

    Presently analogWriteResolution is a global setting. Is this necessarily so, or can settings be made to get different resolution settings on different pins?

    The use case is that Teensy4 enables...
  13. I solved the external interrupts problem in this...

    I solved the external interrupts problem in this thread. This technique lets you run the PFM on a single pin instead of wiring two pins together....
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    I got this working on pin4 \ PWM2.0. Thanks for...

    I got this working on pin4 \ PWM2.0. Thanks for the code.
    With this working, you can quite simply implement PFM on a single pin when combined with the techniques in this thread:...
  15. What's the status of Xbee wrt to Teensy4

    I've been using 433mhz modules for a bit and they're giving me some trouble. I have seen Xbee modules used for over-the-air diagnostics and I'd like to try one out either to diagnose 433mhz or...
  16. This basically works straight ahead. I'm using...

    This basically works straight ahead. I'm using digital pins to feed ultrasonic transducers. I was able to modulate the PWM frequency with a sinusoid (to get PFM) and the signal came right through on...
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    Setting up PWM on an unused IO pin and setting an...

    Setting up PWM on an unused IO pin and setting an interrupt on another is exactly what I'm doing presently. This is super lame since its using up an extra pin...but it works.

    I'm primarily...
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    Teensy4 PWM interrupt config

    I am setting up PWM output on a digital pin. I want an interrupt to fire on the falling edge of the PWM output. At present, I can't get both the interrupt and the PWM configured simultaneously: If I...
  19. Teensy4 PWM frequency modulation and overhead questions

    I presently have two pins on a Teensy 4 executing PWM at slightly different frequencies such that the voltage difference between the pins are essentially amplitude modulated at the difference in...
  20. Hmmm. If I read the FlexPWM timer documentation...

    Hmmm. If I read the FlexPWM timer documentation correctly, I believe there are three output compare registers per timer. How do I capture an interrupt for each of them? The above makes it look like a...
  21. I saw that, but I need to the vector names to...

    I saw that, but I need to the vector names to implement the ISR unless there's a way to do it with just the IRQ.
    Also, am I too conclude that compare and overflow both use the same IRQ? Obviously...
  22. I need to set an interrupt on FlexPWM compare and...

    I need to set an interrupt on FlexPWM compare and overflow for a particular pin. Pretty simple, just need to know the vector names.
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    Below are the relevant code fragments. I'm...

    Below are the relevant code fragments. I'm working only with pins 23 and 22 presently. I arrived at the frequency settings by trial and error. The pwm frequency only changes in notches of about...
  24. Need table of Teensy4 interrupt mask names

    I need a table for interrupt mask names like the one on this page only for Teensy4.
    https://www.pjrc.com/teensy/interrupts.html

    Any help?
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    With analogWriteResolution set to 11 I can see...

    With analogWriteResolution set to 11 I can see the frequency resolution coming out to about 10.5hz. This is not what I expected per above, so there must be some other calculations I need to...
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    Need to confirm PWM math and syntax

    I need to generate two PWM frequencies around 40Khz separated by about 32hz on a Teensy4. According to the PWM page, it seems I should choose:
    Resolution = 11 bits
    Ideal frequency = 73242 hz
    This...
  27. Working perfectly as near as I can see. Thanks!

    Working perfectly as near as I can see. Thanks!
  28. Interrupts in general or just interrupts...

    Interrupts in general or just interrupts pertaining to those pins?
    I'll be using Intervaltimer objects, and the PWM adjustments may need to be made within one of those ISRs, so it looks like I'll...
  29. Absolutely wonderful! I'll confirm myself when I...

    Absolutely wonderful!
    I'll confirm myself when I sit down tomorrow.
  30. Here's slimmer code: Pressing enter in the...

    Here's slimmer code:
    Pressing enter in the serial interface executes the attempted timer reset on pins 22 and 23. If that works, you should observe the phase difference between their waveforms reset...
  31. As I said, only 23 and 22 are under test...

    As I said, only 23 and 22 are under test presently and they are both on FlexPWM4.
    I'll trim the code down and post it, but at the same I'll still need syntax for the register writes eventually. Any...
  32. Ok...the full program is below. The two pins...

    Ok...the full program is below.
    The two pins I'm seeking to reset are 22 and 23 which are both on FlexPWM4.

    The attempt to resync PWM happens after this line:
    if((command_buf & ...
  33. I need code examples for the FlexPWM register...

    I need code examples for the FlexPWM register manipulation. I don't have any code for that yet. I posted a link to stuff I found online above, but it is for a different NXP part. I've pasted a code...
  34. Excellent. This appears to be exactly what I...

    Excellent. This appears to be exactly what I need, especially with the motor commutator explanation included.

    I'll need some help with the code. I poked around the Teensy4 core files and for code...
  35. I took another run at the documentation and I'm...

    I took another run at the documentation and I'm still short of a solution for what I thought would be a simple problem of resetting a timer count to zero.

    I asked about pinmode and analogwrite...
  36. Thanks for the replies. My use case is simple: I...

    Thanks for the replies. My use case is simple: I need to have a pin output a square wave at a particular frequency and be able to restart the duty cycle so I can sync its phase based on external...
  37. I already found the Teensy PWM page and chose my...

    I already found the Teensy PWM page and chose my pins specifically to have different timers. I was able to measure perfect behavior, so I'm over pin\timer conflicts. I just need to phase-correct the...
  38. How to reset Teensy4.0 timers for phase syncing PWM signals

    The Teensy4.0 has far more timers than the 3.6 which enables some neat use cases I'm pursuing. However, I need to be able to resync the PWM phase (with respect to an external source) by restarting...
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    This was actually a miracle of bad sampling. My...

    This was actually a miracle of bad sampling. My diagnostic output perfectly jumped in the troughs of the square wave I was sampling and falsely output zero the whole time.
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    Odd digitalread problem

    I'm digitally sampling a pin @80khz. The readings are coming back all zero and they should not. I am measuring the pin with a scope and it shows the square wave I am expecting with 3.3v max. If I...
  41. NRF24L01 + Teensy Potential power issue?

    I am integrating an NRF24L01 into a project using the RF24 library in order to replace a bit-banging SPI implementation noted in this thread. ...
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    Drone RC Tx code for Teensy?

    I need to bypass human control of a set of drones and pilot them from a Teensy. I did a basic test of the this code successfully:
    https://github.com/perrytsao/nrf24_cx10_pc

    Unfortunately, the...
  43. Recieving serial data from iPhone headphone jack

    With the onboard DACs on a Teensy 3.6, it's easy to perform FSK or other to implement a serial connection over an audio line. I want to be able to receive the serial data on an iphone via the...
  44. Using Teensy input pin as VCC\GND pin for sensor devices

    I need to save space on my breadboard to keep things neat. As such, I have implementations where I attach a 4 pin device across 4 Teensy pins...and set two of the pins as inputs on the Teensy and...
  45. Need advice on compass parts for Teensy units.

    I need help with magnetometer usage and part selection for a compass use case. I have a QMC5883l up and running, but I can't use the data. I might need to switch units and want to choose wisely.
    ...
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    The magnetometer is a QMC5883L. I'm using...

    The magnetometer is a QMC5883L.
    I'm using basically this code, only with wire1...
    https://stackoverflow.com/questions/60272297/converting-arduino-compass-signal-to-useable-heading

    Regarding the...
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    Can't have missed wire1.begin, or the hang...

    Can't have missed wire1.begin, or the hang behavior wouldn't reproduce. Yes, those are the pins...even if they're reversed there should be signal on the scope...but no.

    There's a lot of other...
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    Yes, wire1. If nothing else, I figured I'd see a...

    Yes, wire1. If nothing else, I figured I'd see a clock signal.
    I reviewed the other thread I read, and its only slave mode they were saying doesn't work yet. So that makes sense now.
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    Teensy 4.0 I2C questions and issues

    I have a Teensy 4.0 and I need to make an I2C magnetometer work using the SDA1\SCL1 pins. Like many others, I am seeing my sketch hang when endtransmission is called.

    I a recent thread states...
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    Ok as of now: No wire.h support for T4. Is that...

    Ok as of now: No wire.h support for T4. Is that on anyone's roadmap to complete?
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