DRV8301: Why DRV8301 SPI SDO has undesired Pulse output?

Hello,

Could you check the SDO pin when there is no connection to the MCU? The SDO pin should be floating except for the scope probe.

Please check the VDD_SPI pin on the scope as well.

Could you share a plot including the SDO/NSCS/SCLK together?

Regards,

-Adam

Thanks for reply.

 There is no connection to the MCU for the SDO SCLK and SDI and nSCS to GND ( noise below 50mV).

The following figures are VDD_SPI, SCLK, SDO, SDI.

Hello,

Your CLK and SDI signals do not look correct. The CLK should be a square wave. Also what are these pulses on your SDI line?

Regards,

-Adam

Hi Adam, thanks for reply.

After changing 5th IC, the problem above has been solved.

But, another question occurs.

Using 3 PWM mode, 30kHz pwm frequency, min. pulse width 20us, deadtime 500ns(150k ohm), CSD18531 mosfet, the h bridge always shoots through when I push the motor shaft from running to stop and at the start of motor running.

Is the deadtime stable? How can I sovle the problem?

Thanks!