TUSB4020BI: TUSB4020BI - Reset requirements

Selvaraj Karuppusamy

Part Number: TUSB4020BI

Hi,

As per our design USB 2.0 TUSB4020BI is connected with a processor on board. "GRSTZ" is having internall pull up so any external Pull ups are not given.

When the Processor goes to sleep mode and then wake up, do we need to reset the TUSB4020BI so that the processor can detect the USB 2.0 HUB attached?

Is there any GPIO based reset required for this TUSB4020BI?

over 6 years ago

0 Malik Barton57 over 6 years ago

TI__Guru 64326 points

Hi,

TUSB4020BI does not require a GPIO based reset. When your processor goes to sleep, is power removed from TUSB4020BI? I believe once the processor wakes up from sleep mode it should try to re-enumerate TUSB4020BI as long as TUSB4020BI is active (GRSTz = high).

0 Selvaraj Karuppusamy over 6 years ago in reply to Malik Barton57

Intellectual 425 points

Hi Malik,

The power to the TUSB4020BI will not be removed while the processor goes to sleep.

0 Malik Barton57 over 6 years ago in reply to Selvaraj Karuppusamy

TI__Guru 64326 points

Hi,

Since the power will not be removed then TUSB4020BI should not need to be reset again. This use case really depends on if the processor tries to re-enumerate TUSB4020BI. Generally standard USB Host have this functionality.

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TUSB4020BI: TUSB4020BI - Reset requirements