[ TS3USB221 ] USB Hub Fail to Perform Reset issue

Kenichiro

Other Parts Discussed in Thread: TS3USB221

[ TS3USB221 ] USB Hub Fail to Perform Reset issue

Hi,

My customer has reported that their USB Hub occasionally fail to perform reset when TS3USB221 switch the route. Circuit is as below.

The TS3USB221 switch cause the reset of USB hub in most of case. However, sometimes (like 4% - 5%), USB hub does not perform reset, even though TS3USB221 is switched.

Q1: Do you have any ideas and/or comments on this behavior?

Q2: Have you seen this before?

Q3: When my customer attempt to change S pin high to low and/or low to high, VCC supplied and OE_ remains low (device enabled). Does this cause any of potential failure?

Thank you for your support in advance.
Please let me know, if you need further information.

Regards,
Ken

over 9 years ago

0 Adam Torma over 9 years ago

TI__Mastermind 45575 points

Ken,

Q1: Do you have any ideas and/or comments on this behavior?

I am trying to get a handle on the procedure to produce your failure mode. Let me know if this is the sequence that produces the failure. Do you have an scope shots of D+, 1D+, S, Vcc pins during a successful reset and failure?

1) You have Vcc powered to 3.3 V and OE set low

2) You have S pin set high and initiate a reset command on the D+/D- bus from your controller's PHY to PC1

3) Then you try to reset PC2 by setting S pin low and send the same reset commend on the D+/D- bus from your controller's PHY to PC2

4) but 5-% of the time PC 2 doesn't reset

5) This could also happen on PC1 if switching the other way?

Q2: Have you seen this before?

I cannot say if I have seen this before until I understand more about what is happening

Q3: When my customer attempt to change S pin high to low and/or low to high, VCC supplied and OE_ remains low (device enabled). Does this cause any of potential failure?

Having Vcc powered up and OE pin set low will not cause any issues while toggling the select pin.

Thank you,

Adam