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DRV8889-Q1: Open-Load Detection

Shinichi Yokota
Genius 9715 points
Part Number: DRV8889-Q1

Hello,

This question is relevant to my post "DRV8889-Q1: Device Behavior".

I'm still wondering how to detect an open-load condition correctly with DRV8889-Q1 even at an electrical angle of 0°, 90°, 180°, or 270°. I thought one way was to monitor OL_A or OL_B bit of DIAG Status 2 register. If I knew the current electrical angle of the DRV8889-Q1, I could mask the status of OL_A or OL_B by MCU when the angle was at 0°, 90°, 180°, or 270°.

How can I know about the current electrical angle of DRV8889-Q1?

Best regards,
Shinichi Yokota

  • 0
    TI__Guru 56650 points

    Yokota-san,

    The host controller has to record how many steps are sent out and count the current electrical angle for each micro-stepping.

    For current DRV8889-Q1, if the motor stays in 0°, 90°, 180°, or 270° angle longer than 80ms, the open load detection would be reported. Yes. Please mask the status of OL_A or OL_B by MCU when the angle was at 0°, 90°, 180°, or 270° if the motor stays on that angle over 80ms.

    Or, do a filter on OL_A or OL_B: when OL_A or OL_B is reported, move the motor one more micro-step away. If OL_A doesn't be reported on the new step. The original OL_A is not true.