DS90UB940N-Q1: DS90UB948 I2C ADDR ERROR

Hi Jaradat,

Thank you for your help.

You mean I2C ADDR maybe depand on I2C bus pull up resistors？

This ADDR only depand on IDx pull up/pull down resistors?

do you mean this i2c ADDR depands on IDx and also depands on I2C pull up resisters?

This I2C is using ffor touch pane, the 948 I2C address is dump from 947, I think 948 I2C address is depands on IDx?
power on /off/on/off quickly is easier to reproduce problems. My question is 948 i2c address sometimes not right as IDx set.Thank you!

Best regards,

Hello Zhonghui,

The I2C address depends only on IDx. However, having wrong I2C pull-up resistors may results in not detecting the corect signal.

Hi Jaradat,

Thank you for your help.

I think this pull up resistors not influence the 948 ADDR, Only can influence touch panel I2C ADDR. So why 948 I2C ADDR will sometimes changed？

My 948 is connected through 947, and the address of 948 is also read through 947. 948 connects the screen and touch screen, but why does the 948 address read by 947 change? And fast up and down points are easier to appear?

Best regards,

Hello Zhonghui,

you need to make sure you have the correct power-up sequence on both devices, SER and DES. Also please make sure you maintain the I2C ready delay by waiting minimum 2ms before sending any I2C command to the SER/DES.

Hi Jaradat,

Thank you for your help.

Could you help provide the power up sequence? And how to know the I2C ready? Thank you!

Best regards,

Hello,

 These are always described in all datasheets. For example in the 948 d/s please refer to section "9.1 Power-Up Requirements and PDB Pin". The power-up timings can be found in Table 9-1