2 Replies Latest reply on Mar 19, 2015 2:59 PM by ForumMigrationAdmin

    I2c - tiny bit of advise please

    ForumMigrationAdmin

      I have just updated the arduino edison with latest mraa and upm. Have also (finally after a minor screw up) updated the idea with latest mraa and upm. Now have linked against the upm module hmc5883l and have got data from it. The I was going to contemplate writing the UPD module for a barometric sensor MPL3115A2 - but to my joy found it is in the latest upm. Connected it up and added the code (shamelessly stolen from and example) and ran it. Getting weird results and errors such as;

      Pressure Value:  0.00 Altitude: -1.00 Sealevel: 44330.00 Temp:  0.00

      Write to trigger measurement failed

      Error sampling temperature

      Pressure Value:  0.00 Altitude: -1.00 Sealevel: 44330.00 Temp:  0.00

      Write to trigger measurement failed

      Error sampling temperature

      Pressure Value:  0.00 Altitude: -1.00 Sealevel: 44330.00 Temp:  0.00

      Write to trigger measurement failed

      Error sampling temperature

      Pressure Value:  0.00 Altitude: -1.00 Sealevel: 44330.00 Temp:  0.00

       

      (NOTE: The hmc5883l was also on the bus but I wasn't asking it anything....) Note also (which is where the question is coming from, I had not pullup resisters on the i2c bus).

      I captured the i2c data on my logic-8 and accidentally had the analog display on and notice the i2c signals only reach (just) 4 volts.

      As a bit of a neophyte, is this a sign that pull-ups would be required?