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  • Legality of SPI to I2C bridges

    I was looking through the forum, and this IC was ruled legal in post #4 of this forum, providing it was used in a module. First of all, what does that entail? Secondly, it seems that in the post referred to it would control a light strip. My question is, would it be legal to control an arbitrary non-user-programmable SPI sensor through the I2C busses of the REV Hub, using this IC (no module)? And would the above be legal if it was used in a module? Thanks.

  • #2
    The game Q&A question & answer is:



    Subject: I2C to SPI Bridge Module

    Question:
    May we use an SC18IS602 I2C to SPI Bridge Module to control addressable LED strips? ...

    Answer: The part number referenced is a IC, not a module. If it is used in a module that does not include the user programming, it would be allowed.



    I believe Team 4634 is correct. The SC18IS602 I2C to SPI Bridge Module is a module, not a IC. This module appears to have two ICs on it:
    • an Arduino compatible processer IC (14 pins), and
    • the SC18IS602 IC (16 pins)
    The processor on the bridge module can be programmed with the Arduino IDE. For example, suppose you wanted to render a custom animation on the SPI LED strip(s) connected to the bridge module. Instead of coding the rendering of the animation into your opmode, you can code it onto the Arduino processor of the bridge module; thereby offloading the rendering of the animation from the RC phone to the processor on the bridge module. This is not legal for competition, however it would be awesome experience for the kids to do this type of Arduino programming as a side project.

    <RE12>.c says it would only be legal to use a bridge module such as this to control the components listed in <RE12>.b (i.e. light sources).

    Comment


    • #3
      Originally posted by Alec View Post
      The game Q&A question & answer is:



      Subject: I2C to SPI Bridge Module

      Question:
      May we use an SC18IS602 I2C to SPI Bridge Module to control addressable LED strips? ...

      Answer: The part number referenced is a IC, not a module. If it is used in a module that does not include the user programming, it would be allowed.



      I believe Team 4634 is correct. The SC18IS602 I2C to SPI Bridge Module is a module, not a IC. This module appears to have two ICs on it:
      • an Arduino compatible processer IC (14 pins), and
      • the SC18IS602 IC (16 pins)
      The processor on the bridge module can be programmed with the Arduino IDE. For example, suppose you wanted to render a custom animation on the SPI LED strip(s) connected to the bridge module. Instead of coding the rendering of the animation into your opmode, you can code it onto the Arduino processor of the bridge module; thereby offloading the rendering of the animation from the RC phone to the processor on the bridge module. This is not legal for competition, however it would be awesome experience for the kids to do this type of Arduino programming as a side project.

      <RE12>.c says it would only be legal to use a bridge module such as this to control the components listed in <RE12>.b (i.e. light sources).
      Alec, this bridge module does not have an Arduino compatible processor on it. The two chips are the bridge chip itself and a TI CMOS logic quad buffer. Furthermore, even if there were an Arduino compatible chip on there, you would need to desolder it from the PCB to program it, as the programming pins are not exposed to the connectors. The product page simply says they have an Arduino compatible library for interfacing to it, in this case it's an I2C library.

      Comment


      • #4
        The 14 pin IC looked like a ATtiny processor. Thanks for the correction!

        Comment


        • #5
          Originally posted by Alec View Post
          The 14 pin IC looked like a ATtiny processor. Thanks for the correction!
          Also just FYI, a 30-LED APA102 strip can be controlled at over 70FPS from the REV Hub (if that's the only thing your program is doing hahaha) but, since it's allowed to connect the two Hubs over USB instead of RS485, you could use the entirety of your bandwidth to the second hub just for fancy LED strip patterns if you so desired.

          (If connected over RS-485, any command sent to either Hub locks the primary Hub's USB bus until a response is received, whereas if both are connected over USB, you can be sending commands to both at the same time)

          Comment


          • #6
            Originally posted by Alec View Post
            The game Q&A question & answer is:



            Subject: I2C to SPI Bridge Module

            Question:
            May we use an SC18IS602 I2C to SPI Bridge Module to control addressable LED strips? ...

            Answer: The part number referenced is a IC, not a module. If it is used in a module that does not include the user programming, it would be allowed.



            I believe Team 4634 is correct. The SC18IS602 I2C to SPI Bridge Module is a module, not a IC. This module appears to have two ICs on it:
            • an Arduino compatible processer IC (14 pins), and
            • the SC18IS602 IC (16 pins)
            The processor on the bridge module can be programmed with the Arduino IDE. For example, suppose you wanted to render a custom animation on the SPI LED strip(s) connected to the bridge module. Instead of coding the rendering of the animation into your opmode, you can code it onto the Arduino processor of the bridge module; thereby offloading the rendering of the animation from the RC phone to the processor on the bridge module. This is not legal for competition, however it would be awesome experience for the kids to do this type of Arduino programming as a side project.

            <RE12>.c says it would only be legal to use a bridge module such as this to control the components listed in <RE12>.b (i.e. light sources).
            Why would a module be allowed for controlling lights, but not sensors. It seems that the main thing that will do is make inspectors miserable?

            Comment


            • #7
              Originally posted by DaSadRhino View Post

              Why would a module be allowed for controlling lights, but not sensors. It seems that the main thing that will do is make inspectors miserable?
              We're not the GDC... you should ask them directly :P although they'll probably just quote <RE17> on you.

              Comment


              • #8
                Lol I don't have the team account password.

                Comment


                • #9
                  Originally posted by 4634 Programmer View Post

                  Also just FYI, a 30-LED APA102 strip can be controlled at over 70FPS from the REV Hub (if that's the only thing your program is doing hahaha) but, since it's allowed to connect the two Hubs over USB instead of RS485, you could use the entirety of your bandwidth to the second hub just for fancy LED strip patterns if you so desired.

                  (If connected over RS-485, any command sent to either Hub locks the primary Hub's USB bus until a response is received, whereas if both are connected over USB, you can be sending commands to both at the same time)
                  It is great that you asked the GDC to officially allow the second expansion hub to connect directly to the phone via a USB hub, instead of the RS-485 link to the first expansion hub. Great work FROGbots!

                  I hope the GDC will eventually allow Arduinos and other co-processors so that kids can gain valuable experience on these pervasive processors, and so that kids can understand the need to use co-processors for certain applications.

                  Comment

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