DRV8889-Q1EVM: My SPI behaves weirdly

Hi, 

Please give us a couple days to respond to this. 

Regards,
Karan

Hi Viji,

Thanks for the post. Based on the screen capture it appears you have the decoder setting for the Logic incorrect. Please see below capture example for the same device EVM. Note the SPI clock active edge. Also refer to the datasheet page-44, Figure 7-32. SPI Transaction. Make sure the MCU SPI mode and the Logic decoder settings are correct.

See below the decoder settings used for the above capture. I hope this will help resolve your issue with the SPI. Thanks.

Regards, Murugavel

Thank you for the output.

My response for x04000 is not 0xC000.

But when I try to write to my Motor driver the value is not persisting.

I am sorry to bother actually I am new to this driver.

There is a typo in the previous comment my response for 0x4000 is 0xC000

Hi Viji,

0xC000 response for 0x4000 suggests there were no error registered in your system. This is normal expected response. 

Based on your datagram you were writing to register 0x05 a value of 0x03. The read value in this transaction will show the previous data before write. So you were getting 0xC000. If you do a (read or another write) to 0x05 register you will see the value 0x03. 

Regards, Murugavel

I understand this,

But i am continuously writing 0x03 to to register 0x05. All my responses are the same. I mean after my first write of 0x03 to 0x05 register  my second write to 0x05 register should give back  0x03 to my read back gives the same response of oxC003.

But I am always getting 0xC003. 

I mean I am always getting 0xC000. I am think more like my spi write is failing.

Hi Viji,

Did you use TI EVM or built a PCB and testing with it? Can you read CTRL8 register and verify if you're able to read 0xC003? Then read CTRL4 and tell us what do you read out? Thanks.

Regards, Murugavel

I am using the EVM board but I use an external controller to control the motor. 

When reading CTRL8 register I get  0xC002.

When reading CTRL4 register I get 0xC030.

Thank you this works