TUSB7320: USB drive adjustment function

hisashi yoda

Part Number: TUSB7320

Please let me know if there is a register that can adjust the drive capacity of D + (USB_DP_DN2) and D- (USB_DM_DN2) of TUSB7320.

over 4 years ago

0 Malik Barton57 over 4 years ago

TI__Guru 64326 points

Hi,

There is no register to modify drive capability of USB 2 interface.

0 hisashi yoda over 4 years ago

Intellectual 640 points

Thank you for your answer.

0 Malik Barton57 over 4 years ago in reply to hisashi yoda

TI__Guru 64326 points

No problem!

0 hisashi yoda over 4 years ago in reply to Malik Barton57

Intellectual 640 points

Please tell me the drive capacity (XX [mA] as an example) for D + (USB_DP_DN2) and D- (USB_DM_DN2) of TUSB7320.

Also, with this terminal, does the drive capacity change between startup and steady operation?

0 JMMN over 4 years ago in reply to hisashi yoda

TI__Guru 60870 points

Hello Hisashi,

A typical USB 2.0 implementation uses 17.78 mA HS current drivers to achieve 400 mV signaling with the 45 ohm to ground terminations at either end of the bus.

Regards,

JMMN

0 hisashi yoda over 4 years ago in reply to JMMN

Intellectual 640 points

In addition, please tell me about the drive capacity.

Is it possible to change the drive capacity of D + (USB_DP_DN2) and D- (USB_DM_DN2) at startup and during USB communication (previous answer)?

The intent of the question is that when determining the USB communication mode (high speed as an example), D + and D- operate on a single end rather than a differential signal.

At that time, an undershoot occurs in the signal on the device side.

We are investigating whether there is a countermeasure to suppress undershoot.

0 Malik Barton57 over 4 years ago in reply to hisashi yoda

TI__Guru 64326 points

HI,

Unfortunately there is no ability to change drive capacity at startup. Could you share waveform here for review?

0 JMMN over 4 years ago in reply to hisashi yoda

TI__Guru 60870 points

It is not possible to change the drive capacity using a register setting just at startup, but the USB 2.0 drive strength can be adjusted by lowering the R1EXT resistor to 8.5K or similar.

Regards,

JMMN

Interface

Interface forum

TUSB7320: USB drive adjustment function