TUSB4020BI: if i connect USB-RS232(USB) cable to USB hub down port main port is disconnecting

SIVA NAGESWARARAO

Part Number: TUSB4020BI

Hi all,

In our design we are using USB hub(TUSB4020BIPHP ),hub having two down stream port one port connected to micro controller one port connected to external usb interface purpose.

Issue: if i connected USB-RS232(USB ) to external usb interface port main port is reseting why ?

For your reference i am attaching schematics1072.USB HUB.pdf

Thanks,

siva

ph: 9676754920

over 6 years ago

0 Gerasimos Madalvanos66 over 6 years ago

TI__Intellectual 1350 points

Hello Siva,

Could you provide some clarification (eg. a block diagram) of how everything is connected? Also, does this only happen with the USB-RS232 or do other devices not work as well? Could you provide what the device appears as in device manager?

Best,
Gerasimos

0 SIVA NAGESWARARAO over 6 years ago in reply to Gerasimos Madalvanos66

Intellectual 270 points

Hi Gerasimos,

1. please look at below bloack diagram

2. This only happen with the USB-RS232 or do other devices not work as well?

Yes, it is happend with USB-RS232

0 SIVA NAGESWARARAO over 6 years ago in reply to SIVA NAGESWARARAO

Intellectual 270 points

Hi ,
Kindly remainder ..

0 JMMN over 6 years ago in reply to SIVA NAGESWARARAO

TI__Guru 60870 points

Siva,

Do you mean when you attach the RS-232 device to the external port, the MCU gets a USB reset? That is caused by the USB host driver, not the TUSB4020B.

Can you confirm if attaching other devices to the external port also results in a reset to the main port?
Does the main port continue working after the reset?

Regards,
JMMN

0 SIVA NAGESWARARAO over 6 years ago in reply to JMMN

Intellectual 270 points

1.Do you mean when you attach the RS-232 device to the external port, the MCU gets a USB reset?

Yes

2. That is caused by the USB host driver, not the TUSB4020B.

Host driver means(by default laptop driver) or we are installing USB hub drivers(provided by TI) that one ?

3.Can you confirm if attaching other devices to the external port also results in a reset to the main port?

4.Does the main port continue working after the reset?

no, if we disconnect cable and connect it works

Thanks,

siva

0 JMMN over 6 years ago in reply to SIVA NAGESWARARAO

TI__Guru 60870 points

Hi Siva,

Can you send a screen capture of what the Device Manager looks like after the RS-232 is attached to the TUSB4020B? If the RS-232 illegally sends SE1 bus state, it could put the hub in programming mode.

Regards,
JMMN

0 SIVA NAGESWARARAO over 6 years ago in reply to JMMN

Intellectual 270 points

Hi,

I will share

Interface

Interface forum

TUSB4020BI: if i connect USB-RS232(USB) cable to USB hub down port main port is disconnecting