TUSB2046B device attach/detach

Matthew Singer

Other Parts Discussed in Thread: TUSB2046B

I am using a TUSB2046B attached to a Freescale K60 running MQX. When a device is in attached to the hub when the USB stack starts, that device is enumerated just fine. However, if the device is then detached or it is attached after the initial enumeration, no status change (or interrupt of any kind) is received by the processor. Is there any configuration to the device that would cause this?

over 13 years ago

0 Elias Villegas M. over 13 years ago

TI__Guru* 76130 points

The hub supports hot plug, there should be no problem.

Can you send your schematics?

Regards.

0 Matthew Singer over 13 years ago in reply to Elias Villegas M.

Prodigy 40 points

Unable to send schematics, but a partial is below. The D+/D- downstream lines all have 15K and 22pF to ground. They then go straight to the connector.

DP0/DM0 go straight to the K60 which has internal pullups.

0 Matthew Singer over 13 years ago in reply to Matthew Singer

Prodigy 40 points

I have put a usb analyzer between port 0 and the host and only see sof's.

0 Matthew Singer over 13 years ago in reply to Matthew Singer

Prodigy 40 points

Pardon me. I meant to say that the K60 has internal pullDOWN enabled.

0 Elias Villegas M. over 13 years ago in reply to Matthew Singer

TI__Guru* 76130 points

Hello Matthew,

Check the power rail of the TUSB2046 to met the specification.

Check the differential impedance on DP0/DM0 to be 90 ohm, (you can accomplish this by placing a 33 ohm series resistors on DP0 and DM0.

Check you have installed a 1.5K pull-up on DP0 for full-speed, or installed on DM0 for low-speed.

When your downstream devices are not recognized, is the SUSPEND output on the TUSB2046 active?

Regards.

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TUSB2046B device attach/detach