DS90UB925Q-Q1: DS90UB925 / DS90UB926 lost of lock issue

Hi Kygo, 

Just a couple quick questions to ensure I understand the issue:

• Is LOCK low in this test condition? 
• Is I2C being ran from 925 or 926? If lock is low, and I2C from 925 to 926 is tried, a NACK is expected.
• If I2C is local at 926, can an ACK be received? 

Regards, 
Logan

Hi Logan

Thank you!

reply as below,

1. During testing, LOCK is High.
2. Customer motherboard is MCU then I2C directly to 926. 925 is not used.
3. MCU I2C directly reads register to 926, 926 does not have Ack

Is there any other place to set DS90UB926 to I2c Slave mode, or is there any other reason for DS90UB926 NACK? THX

Hi Kygo, 

What do you mean the 925 is unused?

So the MCU is on the same PCB as 926 and attempting to do local I2C transaction, not over the link from the 925 board? Can you please clarify?

Regards, 

Logan

Hi Logan 

Yes , you are right! 

And Does the customer 925& 926 SCH is OK? Do I need to suggest customer modify ?THX

DS90UB925Q線路圖.pdf

Hi Kygo, 

IDX pin is correct for 0x58 (8-bit) address. 

Lets discuss further in meeting on Monday. 

Regards, 

Logan