TUSB8041: Reset USB hub using GRSTz pin

Owen

Part Number: TUSB8041
Other Parts Discussed in Thread: TUSB8042A

I am trying to hold the hub in reset by connecting the GRSTz pin directly to ground. And I am not getting the hub to go into reset and it is using twice as much current.

Any suggestions? I also pulled the capacitor on the GRSTz pin. Is this the same behavior on the TUSB8042A?

over 4 years ago

0 JMMN over 4 years ago

TI__Guru 60870 points

Hi Owen,

The hub goes into an undefined state when it is reset, so it can pull power similar to the SMBUS programming current shown in the datasheet. That said, the hub should stay in reset when GRSTZ is held low, what is the behavior you are seeing when the reset is held low?

Regards,

JMMN

0 Owen over 4 years ago in reply to JMMN

Prodigy 175 points

I am able to get the hub to go into reset. I was under the assumption that putting the hub into reset would reduce power draw.

Is there any other way to get the hub into a low power state?

Thank You!

0 JMMN over 4 years ago in reply to Owen

TI__Guru 60870 points

Hi Owen,

The lowest possible power states are going to be the USB suspend (USB 2.0 in L2/USB 3.0 in U3) state or disconnected state (USB_VBUS off).

Regards,

JMMN

0 Owen over 4 years ago in reply to JMMN

Prodigy 175 points

Great Thank You!

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TUSB8041: Reset USB hub using GRSTz pin