TUSB4020BI: Configure slave address if use two TUSB4020BI

Ray Chang

Intellectual 1345 points

Part Number: TUSB4020BI

Hi Team,

According to the datasheet, the bit 2 of slave address could be configured by pin GANGED/SMBA2/HS_UP.

However, the following picture describes that SMBus slave address bits 2 and 3 are always 1 for the TUSB4020BI.

Based on the same FULLPWRMGMTz/SMBA1 configuration, if we have two TUSB4020BIs on the same SMbus,

How do we configure their slave address to different number?

over 7 years ago

0 JMMN over 7 years ago

TI__Guru 60870 points

Hi Ray,

The customer can change FULLPWRMGMTz/SMBA1 to differentiate the devices. The SMBUS setting of the fullpwrmgmt bit in the register will overrride the FULLPWRMGMTz pin setting.

Regards,
JMMN

0 Terry Wu2 over 7 years ago in reply to JMMN

Expert 2110 points

Hi JMMN,

No problem for SMBA1 pin setting. .

Can SMBA2 pin also determine tusb4020b slave address ?

Another question. Does 8 inch mean uplink+downlink total ?

Minimize the trace lengths of the differential pair traces. Eight inches is the maximum recommended trace
length for USB 2.0 differential-pair signals. Longer trace lengths require very careful routing to assure proper
signal integrity.

TKS !

0 JMMN over 7 years ago in reply to Terry Wu2

TI__Guru 60870 points

Hi Terry,

From my lab test today, it looks like SMBA2 pin will also affect the SMBUS address. I am trying to determine where the note in the datasheet originated.

8 inch pcb trace length is from connector to hub, so:

upstream connector - 8 inch of PCB trace - hub - 8 inch of PCB trace - downstream connector

Regards,
JMMN

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TUSB4020BI: Configure slave address if use two TUSB4020BI