DRV8889-Q1: SIMPLE Biasing the motor by just control STEP, VREF, DIR PIN's

Mahmoud,

PWM pulse is different than STEP pin pulse. PWM pulse is automatically controlled by the DRV8889-Q1 regulation loop.

DRV8889-Q1 is a SPI control device. To get a simple hardware control stepper motor driver, please check www.ti.com/.../DRV8436

BTW, to drive a motor, please check the reference design and provide other input pins correct voltage. 

Yes , i know it's a SPI control device ,actually i have red the datasheet and i have the chip and the motor ,but iam asking if i didn't send the SPI commands i think all the write registers have their default values,so can i just send repetitive rising edges to invoke the motor to get step forward?

Hello,

Please pull-up nSLEEP pin; keep DRVOFF pin low and set correct voltage on VREF pin to set correct full scale current.

Hello Wang Li ,

Actually i have pulled up nSLEEP pin after connecting DRVOFF to GND ,then i have connected VREF signal to 3.3v ,then i have connected the STEP pin to PWM signal with freq 333 Hz with Duty 50% but there is no output , but the circuit consume 335mA ..You have any comment for this design?,

Should i set the "DIS_OUT" bit in CTRL2 Register!!

Mahmoud,

"DIS_OUT" default value is 0 that won't block the output.

The circuit consume 335mA. Do you have a scope to monitor output voltage and current? I wound think the motor doesn't move for other reason.