DRV8462EVM: GUI issue

Hi Higa-san,

1. I compared the settings in the widget vs. register values and did not find any mismatch. Initial Learning Current values matched the ATQ_CTRL4 bits 7:3 per datasheet as well as Current Steps for Learn and Current Cycles for Learn values matched the corresponding bits in the ATQ_CTRL15 register. 

I am unable to follow your scope captures. Could you please verify the registers bits described are correctly set? If not please let me know which bits are not exactly matching.

2. Torque DAC Setting: This widget is provided as an user friendly way of setting the value in percentage. The back-end of this setting is the 8-bit TRQ_DAC register. In the Register Map page of the GUI you can change the register values in steps of 1 using the up and down arrow controls. See below. If you were using the widget to input percentage values it may be possible there was a calculation round off and value jumping to the nearest rounded off value. This is expected behavior, not a bug. The reason is we rounded off the widget percentage display to two decimal points and calculate the register values from that percentage value. This would not affect performance. Note this behavior is only with the EVM and GUI. In the customer application they would be directly configure the  TRQ_DAC register in steps of 1, between 1 and 255. 

Regards, Murugavel 

Hi Higa-san,

Please let me know if any updates. Thanks.

Regards, Murugavel

Hi Murugavel-san

I'm sorry for the delay.

1.I checked the appropriate register again.
Again, ATQ_CTRL15 does not match the settings shown in the datasheet and the values set from the GUI window.
Selecting '64' in the learn step of the GUI sets 1d=01b in the register setting window.
I believe 3d=11b is set here according to the datasheet, am I wrong?
Even if I check the current waveform during learning, the amplitude becomes smaller when I change the Current steps for Learn=32 setting to 64, so the register setting is an unintended value.

I confirmed it with Ver0.1.0 as you recommended.

2.Are you saying it doesn't matter that you can't configure it from a GUI widget?
I received the following feedback from a customer.We are receiving very critical feedback from our customers.
You recommended setting the TRQ_DAC directly to the register instead of using the GUI widget. My customer says there is no advantage to using a GUI then.
GUI is a tool that allows you to intuitively and easily recognize which values are being set, right?

Best regards,

Higa

Hi Higa-san,

1. I checked once again. This register field got updated with the correct values when GUI v1.0.1 was updated for production silicon registers definition compliance. This issue should be fixed in the GUI v1.0.1, https://dev.ti.com/gallery/view/MotorDriversBSM/DRV84xx_DRV82x2_DRV89x2-EVM-GUI/ver/1.0.1/. If v1.0.0 desktop GUI app was installed already an "UPDATE CHECKER" message will notify the user of the new GUI version availability. This issue may still exist with the pre-production GUI v0.1.0. This would be an errata with the v0.1.0 GUI and there are no plans to fix it. 

2. The skipped values were due to round off errors. The GUI has numerous functions and operating modes. While these round off errors had little to no impact with the operation of the device, we agree 100% with the customer the GUI must be as accurate as possible and user friendly at the same time. We appreciate the customer feedback. This helps us to constantly improve our GUI for best user experience and device evaluation.

That said I believe the round off error related issues with the "Torque DAC Setting" and "Stand Still Current" percentage values were corrected in GUI v1.0.1. Please try with the updated GUI and let us know if this resolved the issue for the customer.

Regards, Murugavel