11 Replies Latest reply on Dec 7, 2014 5:29 PM by shawn.simonson

    Interfacing MMA7455 SPI to CY8Kit-042

    shawn.simonson

       Hello,

         

       

         

      I'm at my wit's end with this, but I absolutely cannot for the life of me get this accelerometer to work with this board in any way shape or form. I first tried I2C, but this plain does not work despite the fact that the sensor claims to support I2C. I keep getting NACK's back when sending a start with the correct slave address. 

         

      So I'm trying SPI. This *appears* to work. I'll send the master control data to the master control register, however when I attempt to read back the status register from the rx buffer, the rx buffer simply contains the very last data I sent from the tx buffer. To be clear, the break out board does not support 4-wire SPI, only 3-wire (bidirectional) which is how I have it set up. 

         

      The sensor's data sheet is: http://parallax.com/sites/default/files/downloads/28526-Freescale-MMA7455L-Device-Documentation.pdf

         

      Of particular interest are pages 9 and 18. 

         

      I've done everything I can possibly do over the course of 2 weeks to get these two devices to play nicely and they just don't seem to want to whatsoever. I've attached the workspace.