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Type: Posts; User: JimKazmer

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  1. Replies
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    Kurt, if you're working with something that uses...

    Kurt, if you're working with something that uses DMA with repeated/ongoing transfers, and you want to minimize address/data bus contention (due to most of the 16 DMA channels actively doing similar...
  2. Yes, I am familiar with that technique. Time...

    Yes, I am familiar with that technique. Time required per quanta of work is likely the core principle behind such metrics. Knowing average loop-time, max loop time, std-dev loop time, and histogram...
  3. Yes, I am heading in that direction. I'd like to...

    Yes, I am heading in that direction. I'd like to include functions from some of the (IO) subsystems on the Teensy to measure more than just the CPU impact.


    I have an RIGOL DS1054 (4 channels,...
  4. Measuring Code Efficiency; Measuring CPU utilization

    I'm writing some code to control external devices using the Teensy 4.0. I'd like to measure the overhead my code is placing on the Teensy.

    I am using DMA extensively, SPIs, flexPWM, and a few...
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    Miciwan, thank you for this. You provided a...

    Miciwan, thank you for this. You provided a great contextual framework. Some one should promote you from "junior member" to "super helpful member".
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    Those do look interesting... small enough that if...

    Those do look interesting... small enough that if you need more than two, you'd just add another chip.
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    I appreciate your help. I am still optimistic...

    I appreciate your help. I am still optimistic that I (or someone else) will figure out how to make the UART work with the TSB0104 with the Teensy, or explain why it never will.
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    I look forward to it... spent hours trying to...

    I look forward to it... spent hours trying to figure out the issue...
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    Bummer, I bought a bunch of them... The one...

    Bummer, I bought a bunch of them... The one breadboard version of TSX0104 I found was 3x the price of adafruit and sparkfun. Reading through the spec sheets, I cannot see anything that should stop...
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    This refers to the "hardwired" options available...

    This refers to the "hardwired" options available for the pin to connect it to a peripheral. By "hardwired", the processor only allows a certain level of configurability (not every peripheral can be...
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    I tried several settings, like:...

    I tried several settings, like:
    CORE_PIN7_PADCONFIG = ( IOMUXC_PAD_DSE(7) | IOMUXC_PAD_PKE | IOMUXC_PAD_PUE | IOMUXC_PAD_PUS(2) | IOMUXC_PAD_HYS );
    and later
    CORE_PIN7_PADCONFIG = (...
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    From avr_emulation.h:#define CONFIG_PULLUP (...

    From avr_emulation.h:#define CONFIG_PULLUP ( IOMUXC_PAD_DSE(7) | IOMUXC_PAD_PKE | IOMUXC_PAD_PUE | IOMUXC_PAD_PUS(3) | IOMUXC_PAD_HYS )

    IOMUXC_PAD_PUS(3) = 11 PUS_3_22K_Ohm_Pull_Up — 22K Ohm Pull...
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    Digging into the Hardware Serial code: there is a...

    Digging into the Hardware Serial code: there is a place were the PIN is configured, from "HardwareSerial.h":

    typedef struct {
    const uint8_t pin; // The pin number
    const uint32_t...
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    In this case, the device being driven by the 3.3V...

    In this case, the device being driven by the 3.3V side-A is the Teensy 4.0 Pin 7 (UART/Serial RX2 input); the 5V side-B driving device is a RC receiver. I don't have access to that RC-receiver's...
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    I did try that... didn't make a difference. I...

    I did try that... didn't make a difference. I was thinking the Serial library forces it to be INPUT (unless something else is done).
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    Another follow-on question...

    Well, I received my parts and tried them out... they work fine for the SPI, but they do not work for the Serial connection (RX2). The TXS0108E worked for both the SPI and the Serial connection.
    ...
  17. Why? What aspect of servos creates a fire risk?

    Why? What aspect of servos creates a fire risk?
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    I discovered the source of my "glitchy"...

    I discovered the source of my "glitchy" behavior... it had nothing to do with the SPI signal, nor the TXS0108E. The issue was a bad connection in the wiring from the RC-receiver SBUS into the teensy...
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    It seems like very time I browse various websites...

    It seems like very time I browse various websites for products I find new (to me) offerings. I did find a breadboard version of the TXB0104 at adafruit (https://www.adafruit.com/product/1875)....
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    PaulS and BriComp, Thank you for the replies. I...

    PaulS and BriComp, Thank you for the replies. I haven't overcome my skill/fear of soldering those surface mount parts, so I like the product that PaulS recommended. I haven't found a similar...
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    From one of the documents referenced in the...

    From one of the documents referenced in the "support resources" section of the TXS0108E data sheet, I found the answer to #2 and #3: "If the application does not require output enable control then...
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    Logic Level Conversion using TXS0108E

    I've read the many other (Teensy) threads about Logic Level Conversion (and looked at many of the products referenced). I need bi-directional Logic Level Conversion from/to the Teensy 4.0 SPI ports;...
  23. Here are some of the #defines and variable...

    Here are some of the #defines and variable definitions that will likely help if/when you dig into all that code above.

    All that was written almost a year ago, so it is not fresh in my mind. But...
  24. You certainly dug in... Regarding 1...8 (SPI...

    You certainly dug in... Regarding 1...8 (SPI setup); correct on 3...8; For 1 & 2, I set those it up (getting them ready) and then (yes) disable it.

    Regarding ISR_SPI_X_Telemetry, Yes... the nice...
  25. Some details about dShot implementation on Teensy 4

    While I have some pride at having figured this out, I am not proud of my spaghetti code. I do intend to do a re-write and re-structure it so it is useable by others. Until then I am happy to share...
  26. About nine months ago, I implemented...

    About nine months ago, I implemented Bidirectional Dshot 600/1200 with support for telemetry using a Teensy 4.0. It very worked well. I used the SPI peripherals in the manner that MarkT suggested. ...
  27. I (also) needed to know if the ADC continuous...

    I (also) needed to know if the ADC continuous readings were overwritten or not...
    This snippet of code was found in the ADC_Module::analog_init() function:


    #ifdef ADC_TEENSY_4
    // overwrite...
  28. SOLVED: Any known oddities with Teensy 4, SPI1, asserting CS1?

    I've been opening many libraries and reading many posts. Seen many examples of SPI as slave, and SPI1 as master. Still looking for one using SPI1 as slave. Recall reading someone's comment about...
  29. Any known oddities with Teensy 4, SPI1, asserting CS1?

    Using a Teensy 4, I am using SPI and SPI1 (independent from each other) to interact with two separate remote devices. I do the exact same thing with each device: send a command, and receive a...
  30. Teensy 4 maps the internally defined SPI...

    Teensy 4 maps the internally defined SPI peripherals as follows:
    Hardware Peripheral LPSPI4 is mapped to SPI using CS=pin10, MOSI=pin11, MISO=pin12, SCK=pin13
    Hardware Peripheral LPSPI3...
  31. I scoured that card for minutes... and as soon as...

    I scoured that card for minutes... and as soon as I read your response... *kazam*, there it is on the card. Thank you.
  32. Current supply limits for 3.3V for Teensy 4?

    I'm sure this is posted somewhere, but after searching a good bit, I can't find it... I'm sure I read it somewhere.
    Thanks
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    KurtE TeensyDocuments shows more pins... ?

    Thank you for making this available.

    Your document shows many more pins than the "Welcome to Teensy 4.0" card/jpeg shows. For example, your card shows:
    Pin 0: SPI1(3) CS0 (I assume this was...
  34. That is very much what I needed. Thank you! ...

    That is very much what I needed. Thank you!

    Here is the corrected code... not much use to anyone unless you have a scope (and even then there are better things to watch wiggle (only a reference...
  35. Okay... it appears that attachInterrupt(...) is...

    Okay... it appears that attachInterrupt(...) is associated with I/O Pins... It is using my IRQ number (IRQ_LPSPI4=35) (from MX RT1060 table 3-2) as a pin number and compiling with no warnings.

    Is...
  36. Where to find interrupt numbers for Teensy 4? Specifically SPI Frame Complete Int.

    Below is a short test program where I try to attachInterrupt(IRQ_LPSPI4...). It appears I am not using the correct value for the interrupt.
    I am looking at the MOSI signal on a scope and all the...
  37. There must be better ways to connect two...

    There must be better ways to connect two Teensy's... But this is just too perfect of a technique for updating an Electronic Speed Controller (ESC) using dShot 600/1200/2400 every 28/14/7 microseconds...
  38. Yes, but there are some constraints. The...

    Yes, but there are some constraints. The RT1060RM says you should wait for the end of frame (which can be caught with an interrupt). Yet, I think if you can add a new TCR command followed by the...
  39. I am definitely new to this... I got the SPIs...

    I am definitely new to this... I got the SPIs CIRFIFO (circular FIFO) working... It is very awesome! My program can setup the SPI, load up to 16x32-bits of data, and automatically keep the remote...
  40. Anyone have experience using the LPSPIx_CFGR0 CIRFIFO bit?

    This sounds awesome... Loading the SPI transmit buffer with a pre-defined message that you want to repeat, setting one bit (CIRFIFO - Circular FIFO Enable) in a configuration register, and then...
  41. After a bit of digging, I see the the Teensy 4.0...

    After a bit of digging, I see the the Teensy 4.0 SPI Library "maps" the internal LPSPI-4 to the external pins on the Teensy for SPI (CS:pin10,MOSI:pin11,MISO:pin12,SCK:pin13). LPSPI-3 is mapped to...
  42. Are SPI3 and SPI4 accessible? Can both MOSI & MISO be used to x-mit simultaneously?

    I was looking through the (Teensy 4) core code and noticed the definitions for SPI3 and SPI4 were defined. Is it possible to use the pin muxing on the Teensy to make the pins for SPI3 and SPI4...
  43. Most (current) RC electronics are still 5v... if...

    Most (current) RC electronics are still 5v... if I was to switch, would the Teensy 3.5 be a bad choice? Eliminating the electronics for converting between 3.3v and 5v woud be helpful (one less...
  44. Frank, Paul, Thank you for your responses. Both...

    Frank, Paul, Thank you for your responses. Both were helpful to me.

    I am doing a project in combat robotics, which relies heavily on RC technologies. My previous implementation was using an...
  45. How to find implementation details on Teensy 4.0 Libraries?

    I am new to Teensy development. I switched from using a 16Mhz Arduino because it was too slow for the type of real-time robotics control we needed. I had optimized the program to be completely...
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