TUSB1210: Does it support low speed mode?

Archie:

     TUSB1210 does  support USB LS, it has separate LS/FS transceiver inside.

Regards

Brian

Hi Brian,

Customer is using the PHY as device mode. Can you confirm if we can run HS, FS and LS traffic when the PHY is configured as device mode?

Currently, they're able to run HS and FS traffic without issue. But LS traffic is not successful. We suspect the PHY unable to switch to low-speed mode. On the other side, the USB2 host controller port status remain at full-speed when trying to enter low-speed mode.

Can we have details on what need to happen in PHY in order to switch to low-speed?

Regards,
Archie A.

for low speed, XCVRSELECT should be 0x2 and 1.5k pu on D- need to turn on.

Regards

Brian

Hi Brian,

Can you address the following:

[1] Do you have guides on this setting? D/S seems confusing.

[2] When you mentioned 1.5K pull-up resistors on D- need to turn on in order to switch into low-speed, may I know if this resistor are built-in resistor inside PHY or it is external pull-up resistor on D-?

[3] If it is built-in resistor inside PHY, then which register I need to set to turn on pull-up resistor on D-?

Thank you very much.

Regards,
Archie A.

let me check to make  sure.

for device application, TUSB210 can not support  LS.

Thanks

Brian

Hi Brian,

So it is contrary to what you've confirmed before?

Thanks,
Archie A.

sorry for confusion. Just confirmed with designer.

Thanks

Brian

Noted on these, Brian.

May I know what is the limitation in TUSB1210 that making it NOT able to support low-speed mode?
Will low-speed mode works if I provide external pull-up resistor on DM pin?

We are using TUSB1210 as device to emulate HS, FS and LS device. While I understand HS capable device shouldn't support LS, but in this use-case, we just want to emulate LS device.

Thank you.

Regards,
Archie A.

sorry, be patient.

We mentioned it in dallasheet just to follow USB spec.

if you just used as LS, you can add 1.5k PU external on DM and  set XCVRSELECT  to 0x2.

Thanks

Brian

Hi Brian,

Thanks for responding.

Sorry but I am confused with your responses. So, the device can support LS? This query is from a known company and we want to make sure that all information communicated have confirmation from the datasheet.

Can you direct which part from D/S shows it? Hoping to get us clarified.

Thank you very much.

Regards,
Archie A.

Archie:

   Do you know what is the real application for this customer? or they just want to know if it can support for LS? 

Regards

Brian

Thank you, Brian.

I have reached you privately thru email for further assistance.

Regards,
Archie A.