Reading all 0xFFF on DRV8711-BOOST and Fault LED can't be reset

Hi Matthew

Have you checked all the hardware settings and launchpad settings based on the users guide?

After that you can try without motor connected. To see if the nFAULT the same.

Best regards,

Hello Wilson,

Yes, I have checked all of the settings. And I've looked at the device without a motor. There seems to be an issue with the memory--- all of the registers read as 1's. And I'm not able to set them to different values.

Best,
Matthew

Hi Matthew,

Register reads should work as long as the DRV8711 is powered and the connections to the SPI are correct.

The device is powered since the nFAULT LED is on. The SPI connections may be a problem. Can you provide a scope capture of a SPI write and read transaction? Using the Manual SPI Read/Write is the easiest method.

Hello,

Here are some scope grabs. Write operations seem to be working fine. Read operations, as expected, only read 1's. 

This is write to address 0x0 with data 0x000. Blue is the CLK SPI bus and yellow is the SDI. 

This is read address 0x0. Blue is the CLK SPI bus and yellow is the SDO. 

This is write address 0x2 with data 0x0F0. Blue is the CLK SPI bus and yellow is the SDI. 

This is read address 0x2. Blue is the CLK SPI bus and yellow is the SDO. 

I'd also like to note that the SCS bus is operating as expected (high during the duration of the read/write operations). I only have a 2 channel scope, so couldn't also display it.

My guess is that the controller is fried. But my power supply was at 15V and limited to 0.2 A. Trying to figure out exactly where it went wrong. Assuming there were no shorts or misconnections, is it possible to write code that could cause such an error to occur? Also my plan is to resolder the controller onto the board.... how should I check to see if I also need to replace the gate drivers?

Hi Matthew,

It is unlikely that code could affect this.
Has the DRV8711 board worked in the past? Is it a new board?
Also you using a LaunchPad MSP-EXP430G2 with a MSP430G2553?


If you haven't removed the DRV8711 from the PCB, try a few checks with the GUI.

With the Boost-DRV8711 powered to 15V and the GUI open, click the nSLEEP pin.This should send a signal to the DRV8711 to awaken.
You should see the EVM consume more current. The V5 supply and VCP should now be up.
If the DRV8711 regulators do not come up, either the connection to nSLEEP from the Launchpad is suspect or the device is damaged.

You can perform the above checks without the Launchpad by connecting directly to the pin on J1 of the Boost-DRV8711.

Hello Rick,

I figured out the issue. I was using too low of a current limit, so the device was giving a UVLO fault. I'm not exactly sure why I was only able to read 1's from the SPI bus (otherwise I would have been able to see the fault on the FAULT register), but it is probably related to not powering the board to spec. The only unfortunate thing is that I found the error after ordering several more kits haha.

Thanks for your help!

Best,
Matthew

Hi Matthew,

Glad to hear you have it working now. Good luck with your project.