This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV2605LEVM-MD: Unexpected behavior with I2C communications

Part Number: DRV2605LEVM-MD
Other Parts Discussed in Thread: TCA9554, TCA9548A, DRV2605L, TEST

Hi,

I'm working on a project using a Raspberry Pi to drive the 8 drivers off the DRV2605LEVM-MD over I2C.  I had some brief success at first, but have recently run up against an issue where I am unable to communicate with certain I2C devices at seemingly random times.  Here's a summary of what I've tested so far in order to calibrate the driver on driver 2:

set TCA9554 (0x20) control register (0x03) to output port 2 (0xfd, 11111101)
set TCA9554 (0x20) output register (0x01) to enable port 2 (0x02, 00000010)
set TCA9548A (0x70) to enable communications on port 2 (0x02)  // in this case, the tool I'm using requires a register, so I set 0x70 register 0x02 to 0x02 per the datasheet

However, at this point I am unable to access the DRV2605L's themselves.  The i2cdetect command can't see anything at address 0x5a (or 0x58, as I've read in some other questions here), and trying to read/write from it results in a rather descriptive "Read failure" or "Write failure".  Unfortunately, I have not yet been able to do an ocilloscope test -- I can try to get that done if needed.  I can verify that a stable 5V is fed into the Vbat connector, and that the I2C communication lines themselves are secure (I checked this by testing an I2C-based accelerometer on the same bus lines with no errors whatsoever [it's address is 0x1d]).

is this an issue that anyone's run up against?  If so, how was it resolved?  Thanks in advance for any help!

  • Hi, Michael,

    Welcome to E2E and thank you for your interest in our products!

    Could you share your circuit schematic, please? This is to have a better approach to this issue.

    Thank you.

    Best regards,
    Luis Fernando Rodríguez S.

  • Hi Luis,

    I don't have a schematic as it would normally be shown in MultiSim or other software, since I'm more on the programming side than hardware.  What I can share with you is our system layout, which may be slightly less detailed than you need.  I'll link to that here, and try to detail the actual linkages below.

    Raspberry Pi TI DRV2605LEVM-MD
    SDA SDA
    SCL SCL
    5V Vbat
    GND

    Gnd

    I'm drawing power directly from the Pi's 5V pin rather than splice open the power cable running to the Pi.

    While I doubt it makes a difference, the same I2C lines are also connected to a Freescale Semiconductor MMA8541Q 3-axis accelerometer (with an I2C slave address of 0x1d).  I haven't had any trouble accessing that device.

    I've also done some work in the meantime, and have been able to communicate with the board as expected over USB using TI's HCC GUI.

    Thanks for the quick response!