DRV8889-Q1: OL Flag in SPI Register

Shinichi Yokota

Part Number: DRV8889-Q1

Hello,

When an OL (open load) flag is cleared by SPI while the OL condition persists, does it take t_OL (open load detection time) to latch a flag again?

Best regards,
Shinichi Yokota

over 3 years ago

0 Wang5577 over 3 years ago

TI__Guru 56650 points

Yokota-san,

Yes. After the OL (open load) flag is cleared by SPI while the OL condition persists, it takes t_OL (open load detection time) to latch a flag again.

0 Michael Erdahl over 3 years ago

TI__Genius 13455 points

Hi Yokota-san,

The data sheet says the fault will be cleared when the open load condition is cleared and the clear faults flag is set. I will the verify the open load detection logic is latched until the condition is removed and will reply back shortly.

Regards,
Mike

0 Michael Erdahl over 3 years ago in reply to Michael Erdahl

TI__Genius 13455 points

Yokota-san,

It looks like I was replying as Wang was writing his response :)

He is correct - nFAULT will remain asserted until the OL condition is removed.

Regards,
Mike

0 Shinichi Yokota over 3 years ago in reply to Michael Erdahl

TI__Genius 9715 points

Wang-san, Mike-san,

Thanks for your help.

By the way, does the DRV8889-Q1 have an internal delay when an OL condition is removed? If yes, how long is it?

Best regards,
Shinichi Yokota

0 Shinichi Yokota over 3 years ago in reply to Michael Erdahl

TI__Genius 9715 points

Mike-san,

If Wang-san's answer is correct, t_OL should be inserted for every clear faults command until the OL condition is removed. But, your answer gives me an impression that no t_OL will be added for an OL flag. Could you make it clear?

Best regards,
Shinichi Yokota

0 Michael Erdahl over 3 years ago in reply to Shinichi Yokota

TI__Genius 13455 points

Hi Yokota-san,

I think Wang's answer may not be completely accurate - I checked directly with the design team and the the fault is not cleared through SPI until the fault condition is removed. This was their exact response: "If CLR_FLT bit is asserted, while the OLD condition still remains, the fault is not cleared. OL flags and nFAULT remain low. Only when the fault condition is removed, the fault is cleared after CLR_FLT is sent. OL flags and nFAULT are released."

Regards,
Mike

0 Shinichi Yokota over 3 years ago in reply to Michael Erdahl

TI__Genius 9715 points

Mike-san,

Thanks for your clarification. I drew up a picture that explains the DRV8889-Q1's OL flag behavior.

Best regards,
Shinichi Yokota

0 Michael Erdahl over 3 years ago in reply to Shinichi Yokota

TI__Genius 13455 points

Hi Yokota-san,

Your drawing is very helpful! Yes, this is the correct behavior.

Regards,
Mike

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DRV8889-Q1: OL Flag in SPI Register