• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 29 subscribers
  • Views 536 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8718-Q1: PWM setting through SPI

Chuqiang Wen
Expert 5825 points
Part Number: DRV8718-Q1

Hi team, 

From the datasheet, it says that if higher frequency or precise duty cycle PWM control is not required, the eight half-bridge gate drivers can also be controlled directly through the HBx_CTRL SPI control register.

So I would like to know how to use the PWM setting from register. The HBx_CTRL bit is used to control the output state directly. It seems that in order to set the PWM output through SPI, we need manually toggle the HBx_CTRL bit. Is my understanding correct? If so, how to evaluate the accuracy of duty cycle and frequency? And what is the max output PWM frequency from SPI control? 

Thanks!

'

Ethan Wen

  • 0
    TI__Guru 55605 points

    Ethan,

    This is not the right way.  There are dedicated PWM input pins...4 for 8718.  These can can mapped to outputs and the PWM frequency and duty cycle is controlled externally. 

    If customer insists to use SPI, the update rate with 100% depend on the SPI frequency they are using.  Duty cycle variation will vary depending on how many other devices are connected to SPI.  If they have a dedicated SPI and can control update rate, more precision might be able to be maintained.

    Regards,

    Ryan