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DRV10983Q1EVM: I2C not working

Isaac Parsons
Intellectual 450 points
Part Number: DRV10983Q1EVM
Other Parts Discussed in Thread: DRV10983-Q1

Hi there, I purchased the DRV10983Q1 EVM and after looking at the display tab of the GUI, the values seem to be incorrect (for example its displaying the supply voltage as 0V even though I measured it at the supply pin as 24V). I am unable to upload to the EEPROM, I just get an error saying that the EEPROM is not ready. After looking at the I2C SDA pin I can see that I am sending commands but not receiving anything back from the DRV10983-Q1. 

I also tried just setting a speed without anything connected and I get an overcurrent fault. Not too sure what the issue is.

A few other notes: I am using windows 10 on Parallels (Macbook). The draw from the power supply is 24V and 0.007A 

  • 0
    TI__Expert 6065 points
    Hey Isaac,

    1) Make sure the GUI is not in demo mode. See the top right corner of the GUI to make sure demo mode isn't activated. Also make sure you selected the DRV10983-q1 device in the GUI
    2) I want to make sure you are able to do reads. Try pressing "manual refresh" on the "basic settings" tab of the GUI and see if the read is successful or if you get an error message.
    3) When you say "I also tried just setting a speed without anything connected and I get an overcurrent fault", do you mean the motor is disconnected from the DRV10983-q1 but you still get an overcurrent fault?
    4) I think in your previous issue as well, you saw supply voltage register show 0V. This is concerning. Can you send me screen shots of the GUI pages you have? Im going to order a new EVM for myself to verify if there are any problems with the devices on the EVMs recently.

    Let me also talk to my coworkers.

    Sincerely,
    Sanmesh U.
  • 0 in reply to Sanmesh Udhayakumar
    Intellectual 450 points

    1) it is not in gui mode ( I double checked)

    2) I can press "manual refresh" and I get no error message

    3) ya exactly

    4)

  • 0 in reply to Isaac Parsons
    TI__Expert 6065 points

    1) Change the dead time to 1.08 µs. This might be the thing causing overcurrent. This might also correlate to the voltage register not reading properly. Always follow Table 3. Dead-Time Settings recommendations from DRV10983-q1 tuning guide

    Meanwhile I'll be checking a DRV10983-q1 unit on my end to see what might be the problem.

  • 0 in reply to Sanmesh Udhayakumar
    Intellectual 450 points

    ok so I changed the dead time to 1.08us which solved the over current issue. But Im still getting the same values in the display tab (I tried both setting autorefresh and manually refreshing). I have tried hooking up the brushless dc motor (www.faulhaber.com/.../  ) , when I set the speed to anything less than 10, nothing happens, and any speed I set at 10 or above it seems to move at a fixed speed (fairly slow) no matter what speed I set it at. It also draws around 25mA - 32mA no matter what speed I set it at above or equal to 10.

    Thank you for your help so far, do you have any suggestions as to what might be causing this issue?

  • 0 in reply to Isaac Parsons
    Intellectual 450 points
    also, I just realized I was using the phase to phase resistance as the phase to center tap resistance, but I changed the value to be phase to ct resistance (it was 1.32 changed to 0.66). But it did not fix any of the previously mentioned issues
  • 0 in reply to Isaac Parsons
    Intellectual 450 points

    So after varying some of the parameters I am able to get the motor spinning and displaying values, however setting the speed to anything below 10, the motor doesnt move. And anything 10 or above, the motor stays at a constant 25 hz

  • 0 in reply to Isaac Parsons
    Intellectual 450 points
    Is the motor driver unable to drive a motor less than 5.6Hz?
  • 0 in reply to Isaac Parsons
    TI__Expert 6065 points

    1) Our sensorless driver cannot spin motors at very low speeds in closed loop. The exact cutoff speed really depends on the motor and you would need to experiment to find it out.
    2) If you are trying to spin low speed at open loop, it really depends on the amount of load torque. But you can try to increase the open loop/align current to get more control to spin at lower speeds in open loop.
    2) The value you put in the "Speed" box is the duty cycle level out of 511. So entering a 10 is the same as saying apply a duty cycle % of 10/511 or 2%, which is very small. So please enter faster speeds.
    3) Because you have closed loop disabled, you cant control the speed once it reaches the open to closed loop threshold, as it will stay at that speed. Disable closed loop.
    4) Usually a good handoff speed is around 25Hz to enter closed loop. Are you able to enter closed loop?

  • 0 in reply to Sanmesh Udhayakumar
    Intellectual 450 points
    I am able to enter the closed loop, but I am unable to set a low speed. I tried adjusting the open to closed loop threshold to 0.8Hz but when I do that the motor moves very rough, and I get a BEMF abnormal fault
  • 0 in reply to Isaac Parsons
    TI__Expert 6065 points
    1) I want to clarify something. When the motor is in open loop and hits the open to closed loop threshold speed, then the motor enters closed loop and then goes to whatever speed is associated with the "Speed" duty cycle command you give out of 511. You cant set an exact "Hz" speed in closed loop, just a duty cycle % which will be associated with a speed.
    2) The sensorless algorithm for DRV10983-q1 depends on BEMF to know the position of the rotor. BEMF is proportional to speed, so at very low speeds, BEMF might be too low for the driver to read and thus might not be able to successfully spin in closed loop. 0.8Hz seems like a very slow speed.
  • 0 in reply to Sanmesh Udhayakumar
    Intellectual 450 points
    Ya I understand that, But my thinking was if I set the open to closed loop threshold low, then I will be able to set a lower closed loop speed (say around 120rpm or around 2 hz. But when I set the open to closed loop threshold to 0.8Hz and set a low duty cycle, the motor just stutters and gets an abnormal BEMF fault
  • 0 in reply to Isaac Parsons
    TI__Expert 6065 points

    If your goal is to spin in closed loop at lower speeds, what I would recommend is handoff at higher speeds (like around 25Hz) to successfully enter into closed loop, with a certain high duty cycle set (like 100/511) and then slowly lower the duty cycle and see how low of a speed you can get before closed loop fails.

    Let me know if that works

  • 0 in reply to Sanmesh Udhayakumar
    TI__Expert 6065 points
    Any progress Isaac? Also is there any other help needed from me?
  • 0 in reply to Sanmesh Udhayakumar
    TI__Expert 6065 points
    Hey Isaac, for now I will close this thread. If you need any feedback, just reply to this thread or create a new thread.

    Sincerely,
    Sanmesh U.