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Thread: Replace Teensy 3.2 with Teensy 4.1

  1. #1
    Junior Member hhartvig's Avatar
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    Replace Teensy 3.2 with Teensy 4.1

    Sorry for any inconvenience but I’m a totally newbie to Teensy in terms of development and coding. I’m operating a system used for timing and scoring semi dragrace events. This system is utilizing the Teensy 3.2 with the addition of an Ethernet kit.

    I now want to move forward and update this current, and most of the time fully operational, system and want to know if the 4.1 with Ethernet is compatible with the old 3.2 system?

    The I/O part of the system is fairly simple and consists of 12 independent sensor/contact inputs (6 for each of the two lanes). Output consists of 11 independent LED lamps showing lineup and start procedure indication to the two competitors.

    The actual timing and scoring and controlling the Teensy 3.2 is done by a PC application developed in VB. We aim to reuse this application for now (2023 season) but the UI(X) will require future redesign adding modern Windows design to it.

    To take control and future proof our current investment, my plan is to reverse engineer all the hardware and put it into a more robust PCB design using external consultants. Currently all the hardware is mounted on a multiboard and internally connected using mounting wires. This has caused several system malfunctions over the years and put me in an unnecessary dependency of the original developer whenever a fault is occurring.

    So back to my first question, will it be possible to use the current Teensy 3.2 software on a Teensy 4.1?

  2. #2
    Senior Member BriComp's Avatar
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    Obviously NOT a straight drop in.
    The IO on the 3.2 are 5v tolerant whereas the 4.1 is limited to 3.3v. This problem can be overcome with the use of the appropriate level shifters.
    It's difficult to say much more without seeing both the current code and circuit/wiring.

  3. #3
    Senior Member+ MichaelMeissner's Avatar
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    Cool

    It depends on what you do, and whether you descend into doing low level mucking about or you just use the library functions. Some time ago I wrote a list of differences that I knew of in the unofficial Teensy wiki:


    At a high level some of the changes include:
    • The serial ports other than Serial1 use different pins.
    • Any additional I2C buses are on different pins. The main I2C bus (pins 18 and 19) are in the same location.
    • Any additional SPI buses are on different pins. The main SPI bus (pins 11-13) are in the same location. Note the Teensy 3.2 has the ability to use alternate pins for the main SPI bus, the Teensy 4.0/4.1 does not.
    • As BriComp mentions, the Teensy 3.2 is tolerant of 5 volts on the digital input pins (but not the special pins or analog input only pins), while the Teensy 4.1 can be damaged if feed over 3.3 volts.
    • The I2S audio system uses completely different pins. You need to use the revision D audio adapter instead of the revision C audio adapter.
    • The Teensy 4.1 is 1" longer than the Teensy 3.2.
    • I have a google document spreadsheet that attempts to list all of the pin differences between the Teensys: https://docs.google.com/spreadsheets...it?usp=sharing
    Last edited by MichaelMeissner; 09-10-2022 at 07:15 PM.

  4. #4
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by hhartvig View Post
    ....and put me in an unnecessary dependency of the original developer whenever a fault is occurring.

    So back to my first question, will it be possible to use the current Teensy 3.2 software on a Teensy 4.1?
    Do you have the source code the original developer wrote for Teensy 3.2? At a bare minimum, you'll need that to recompile it for Teensy 4.1.

  5. #5
    Junior Member hhartvig's Avatar
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    Quote Originally Posted by PaulStoffregen View Post
    Do you have the source code the original developer wrote for Teensy 3.2? At a bare minimum, you'll need that to recompile it for Teensy 4.1.
    I have the system in my home - and trying to figure out if I can "read out" the source code in any way ?

    BTW - are you familiar with someone else who have made a dragrace system using Teensy ?
    Last edited by hhartvig; 09-11-2022 at 12:02 PM.

  6. #6
    Junior Member hhartvig's Avatar
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    Thanks highly appriciated

  7. #7
    Senior Member BriComp's Avatar
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    I have the system in my home - and trying to figure out if I can "read out" the source code in any way ?
    It's NOT possible to get the Source code (the text code) out of the Teensy.
    You will need the code from the person who wrote it. Otherwise start from scratch.
    I am sure there are people here that would be willing to help and offer advice.

  8. #8
    Junior Member hhartvig's Avatar
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    Quote Originally Posted by BriComp View Post
    It's NOT possible to get the Source code (the text code) out of the Teensy.
    You will need the code from the person who wrote it. Otherwise start from scratch.
    I am sure there are people here that would be willing to help and offer advice.
    Thanks - that was (unfortunately) also my impression. The idea of starting from scratch is attractive and will give me back the full control - but I will also need a programmer for the windows application. But if the coding etc. used to control the Teensy is fairly simple and documented then this might be the path to follow.

    Next step will be to make a full description of the system functionality. Is there any recomandations of where to search for Teensy freelancers?

  9. #9
    Senior Member BriComp's Avatar
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    Is there any recommendations of where to search for Teensy freelancers?
    I would guess that this is a good place.

    Bear in mind that the Teensy is an Arduino compatible device, though with expansions to make it incredibly better, so Arduino capable persons may also be able to help you.

    I am quite able to offer my services but I am (I guess, you don't say where you are, but I guess from your usage that you are in the USA) on the other side of the world.

    Best to first get the specification of the system together. Don't worry you will get some things wrong, we all do at a first pass, have some discussions here, then move on to implementation.

    It's quite surprising what can be achieved by small simple logical steps.

  10. #10
    Junior Member hhartvig's Avatar
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    Quote Originally Posted by BriComp View Post
    I would guess that this is a good place.

    Bear in mind that the Teensy is an Arduino compatible device, though with expansions to make it incredibly better, so Arduino capable persons may also be able to help you.

    I am quite able to offer my services but I am (I guess, you don't say where you are, but I guess from your usage that you are in the USA) on the other side of the world.

    Best to first get the specification of the system together. Don't worry you will get some things wrong, we all do at a first pass, have some discussions here, then move on to implementation.

    It's quite surprising what can be achieved by small simple logical steps.
    🇩🇰 Denmark

  11. #11
    Senior Member BriComp's Avatar
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    Oh, OK, so similar time zones. That would make things easier.
    Just get on with generating the specification, if you need any help, I am here.

    EDIT:
    As a first suggestion, to ease development, I would use a Serial Interface with the PC, or whatever you chose to use.
    Then when all the logic appears to be working you can change to Ethernet or whatever communications would seem to be appropriate.

  12. #12
    Junior Member hhartvig's Avatar
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    I'll start on the description tomorrow 🙂👍🏁🏎️

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