DRV8308EVM: DRV8308EVM

Mitchel Szazynski

Part Number: DRV8308EVM
Other Parts Discussed in Thread: DRV8308,

Hello, I am using the DRV8308 to drive a 22 pole motor, and right now am having issues with the SPI communication. I have the same issues with both the DRV Evaluation Module and the chip itself soldered to a breakout board. I have tried both the ATMEGA328P Xplained mini kit and an arduino uno as my CPU, and get the same results. I have read the datasheets and reference manuals extensively. The problem is as follows:

I can clearly see that I am writing the proper signals to the DRV, as well as providing it with SCK, but the only "reply" that comes from the DRV is a constant 0xFF (all "1s", always high). I have tried many things and cannot explain why it seems that it is not giving a proper reply (I am not writing all 1s).

Thanks in advance!

over 6 years ago

0 Rick Duncan over 6 years ago

TI__Guru** 114905 points

Hi Mitchel,

We will investigate and reply soon.

Can you provide a scope capture of the SPI transaction?

Also what are the state of the other inputs during this time?

0 Mitchel Szazynski over 6 years ago in reply to Rick Duncan

Prodigy 180 points

Blue one is SCK, Yellow is MOSI (coming from ATMEGA328P, going to DRV8308EVM)

The port for SCS on the atmega328p is set as an output. For this microcontroller, as long as it is set to output, then it makes no difference whether its high or low, because the SCS being an output means that we only have one slave in the system

0 Rick Duncan over 6 years ago in reply to Mitchel Szazynski

TI__Guru** 114905 points

Hi Mitchel,

Please note the Pin Functions states "Active high enables serial interface operation". Also please note in the SPI timing requirements there is a minimum time of 100ns between writes where SCS must be low.

What is the SMODE pin setting? Is it properly set for SPI mode?

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DRV8308EVM: DRV8308EVM