DS90UB934-Q1: I2C address

The IDx circuit looks OK.

What are the values of the I²C pull-up resistors?

Does the I²C master use use 7-bit or 8-bit addresses? Try 0x30 instead. If this does not help, show an oscilloscope or logic analyzer trace of the failed I²C access.

hi Ladisch,

the PULL-UP R is 4.7kΩ. and the rise edge is slow. 

the customer say the I2C signal is bad when connect to 934.

The blue one is SDA and purple one is SCL

The address shown begins with 10110. The 934 address is 0110000.

Hello,

It looks like the edge rate is quite slow, you could try to use a stronger pull-up resistor like 2.2k.  Additionally there seems to be a large amount of crosstalk in your system which could affect the 934's ability to recognize the signal.  Also please verify that you are strapping the 935 for correctly and following the correct power-up sequence.

Regards,

Nick

thanks your reply.

Now I find VDDIO is 2.9V, is there a problem with this voltage?

there is big crosstalk when link  RIN0+ with 933 by POC method.

please explain.

Hi Eric,

I typically recommend that you be as close to nominal as possible however 2.9 is within our datasheet spec.  The crosstalk I see it the clock coupling onto the data line it looks like.  Could this be a measurement problem?  Try to measure just the data line maybe?

Regards,

Nick