DRV8873-Q1: EVM SPI Control Becomes Non-Responsive

Part Number:DRV8873-Q1

Hi,

Background

My customer is utilizing the DRV8873S-Q1EVM unmodified for testing of their motor drive system functionality. They are controlling from a host MCU and are able to start the motor for a while, but eventually the interface and device become non-responsive.

Steps Taken

The following set of instructions are sent to the DRV8873S device:

//Read all registers:

//read Fault
 srcBuff[0]=0x40;
 srcBuff[1]=0x00;
 sendSPI();

 //read Diag
 srcBuff[0]=0x42;
 srcBuff[1]=0x00;
 sendSPI();

 //read IC1
 srcBuff[0]=0x44;
 srcBuff[1]=0x00;
 sendSPI();

 //read IC2
 srcBuff[0]=0x46;
 srcBuff[1]=0x00;
 sendSPI();

 //read IC3
 srcBuff[0]=0x48;
 srcBuff[1]=0x00;
 sendSPI();

 //read IC4
 srcBuff[0]=0x4a;
 srcBuff[1]=0x00;
 sendSPI();


//then write to registers:

//write IC2
 srcBuff[0]=0x46;
 srcBuff[1]=0x00;
 sendSPI();

 srcBuff[0]=0x06;
 srcBuff[1]=0x0C;
 sendSPI();

 //write IC3
 srcBuff[0]=0x08;
 srcBuff[1]=0x4e;
 sendSPI();

 //write IC4
 srcBuff[0]=0x0a;
 srcBuff[1]=0x0b;
 sendSPI();

 //write IC1
 srcBuff[0]=0x04;
 srcBuff[1]=0x70;
 sendSPI();


// After, change to control direction with all the other steps staying the same

 //write IC3
 srcBuff[0]=0x08;
 srcBuff[1]=0x4D;
 sendSPI();

After a period of time, the SPU bus always returns 0xFF and the VCC voltage has dropped down to 0.5V from 5V.

Power was cycled to the board and still the device was non-responsive. No nFAULT indication was seen on D3.

Questions

• Is there a device configuration that can lead to this behavior which is improperly being set?
• Are external protection diodes expected to be added between the board and motor?
• Any other system conditions which may lead to this behavior?

Any guidance is greatly appreciated!

Best Regards,

Mark-