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    Explore Pybytes | Official Documentation | Report a Firmware Bug/Issue | GitHub

    random I2c adresses

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    pycomi2cam2315
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    • T Offline
      tttadam
      last edited by

      Hello there,

      Can you give me some hint? I am expreiencing a weird glitch.
      random i2c adresses showing up on .scan()
      only one am2315 temperature sensor is on a breadboard right now. Thanks
      8601e54d-024d-414a-8169-dde8b59c582f-image.png

      robert-hhR 1 Reply Last reply Reply Quote 0
      • robert-hhR Offline
        robert-hh @tttadam
        last edited by

        @tttadam most likely the pull-up resistors are missing, or another wiring problem, like missing GND connection.

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        • T Offline
          tvetter1976
          last edited by

          I had the same issue and it was not related the the external pull up. Try bus 2 or reduce freqency to lets say 60 kHz.

          robert-hhR 1 Reply Last reply Reply Quote 0
          • T Offline
            tvetter1976
            last edited by

            Once I posted this:
            https://forum.pycom.io/topic/5122/high-speed-i2c-is-not-working-on-bus-0-and-bus-1-hardware-peripheral

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            • robert-hhR Offline
              robert-hh @tvetter1976
              last edited by

              @tvetter1976 That might be. The maximum speed of this sensor is told to be 100kHz.

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              • T Offline
                tvetter1976
                last edited by

                No its written to be 400kHz in this data sheet (p.91):
                https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bno055-ds000.pdf
                Also I tried 400kHz on anothoter microcontroller and it worked. Software I2C on FIpy worked also with 400kHz. I think I also tried Ds3231 on FIPY and had the same disapointing results. So came to the point, that hardware I2C can only be ran only at lower frequencies.

                robert-hhR 1 Reply Last reply Reply Quote 0
                • robert-hhR Offline
                  robert-hh @tvetter1976
                  last edited by

                  @tvetter1976 The OP is using an am2315 Sensor. See: https://cdn-shop.adafruit.com/datasheets/AM2315.pdf

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                  • T Offline
                    tvetter1976
                    last edited by

                    @robert-hh I see. Nice temp sensor. I had the same problems with hardware which should run at 400kHz. Only using bus 2 helped.
                    @tttadam How have you powered the sensor? Are you using 5V? Then you might need a level shifter, isn't it?

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                    • T Offline
                      tttadam
                      last edited by

                      I think the issue was with my breadboard psu... So right now I am using the pycom 3.3V

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