TUSB2E11EVM: When TUSB2E11 works as a peripheral repeater, will it check the digital ping from eUSB device?

Hi Andrew,

Digital pings are only used in a native mode connection, hence the n in eUSPn. If a repeater connection, these digital pings should not be there.

For a repeater connection, Port Reset is used to indicate a disconnect has happened, defined in section 3.3.8 of the eUSB2 spec.

Thanks,

Ryan

Hi Ryan,
Thanks a lot for your prompt reply.
Do you mean eUSPr can use Port Reset to inform eDSPp disconnect event no matter that is a soft disconnect or silent disconnect?
Assume the eUSPr encounters unexpected brownout and disconnected, but eDSPp is still transmitting data,
Is there any EOS concern if the Port Reset from eUSPr is overlapped with the data from eDSPp?

BTW, I cannot find the definition in section 3.3.8 (Control Message Signaling), do you mean section 3.3.9.1?  



Best regards
Andrew

Hi Andrew,

Yes, I mean section 3.3.9.1. I was looking at an older version of the spec, sorry.

Andrew Chien said:

Do you mean eUSPr can use Port Reset to inform eDSPp disconnect event no matter that is a soft disconnect or silent disconnect?

Correct, eUSPr will use Port Reset regardless of which disconnect event occurs. I believe silent disconnect is used primarily for native mode.

Andrew Chien said:

Assume the eUSPr encounters unexpected brownout and disconnected, but eDSPp is still transmitting data,
Is there any EOS concern if the Port Reset from eUSPr is overlapped with the data from eDSPp?

I don't believe there should be any concern for EOS. It would depend primarily on how the disconnect occurs, I.E a HS device being disconnected, or a LS/FS link declaring disconnect. For a LS/FS device, the peripheral repeater is responsible for detecting a disconnect in the connection, not the device/peripheral.

In the spec, for a HS disconnect, it is illustrated simply as the device disconnected, and does not illustrate how the the peripheral device and repeater are meant to act. This is because HS disconnects are handled by the host repeater, while LS/FS disconnects are handled by the peripheral repeater.

Section 5.5.5, 5.5.6, and section 5.5.7 of the eUSB2 spec have more details.

Thanks,

Ryan

Hi Ryan,
Thanks again for your prompt reply.
In section 5.5.5 & 5.5.6, before eUSPr transmit XeSE1 to trigger soft disconnect, the eUSB2 status is idle with eSE0 on eD+/eD-, so there is no EOS concern.
But if eDSPp does not check Digital Ping, it may keep transmitting data after eUSPr encounter brownout reset.
Could you elaborate more about how the peripheral repeater handle it?  



Best regards
Andrew

Hi Andrew,

Let me try to look into this a bit more and see what the expected behavior would be, as the spec does not define the expected behavior in case the device suddenly resets during an active USB2 connection. My initial believe is that seeing SE0 from the device would cause the peripheral repeater to go to default, or that Port Reset from the device restarting will cause the peripheral repeater to enter Reset.

Thanks,

Ryan