TPD12S016: I2C interface failure

Borisav Maksimovic

Part Number: TPD12S016

Hello,

The TPD12S016 interface chip is used between iMX6 and LCD. On 3V3 side there is 4k7 pull up, and this mid level voltage is visible on data line. The I2C bus is shared between LCD, processor, PMIC and when LCD is detached such levels do not appear even when TPD12S016 hot detect enabled (but no LCD present)

What could be the reason?

Thanks,

Borisav

over 5 years ago

0 Michael Tan over 5 years ago

TI__Expert 8420 points

Hi ,

You question we have recieved ! We will reply you soon,!

0 Michael Tan over 5 years ago in reply to Michael Tan

TI__Expert 8420 points

HI Borisav,

What does your mean of "this mid level voltage is visible" ? which pin signal is disappear after the LCD detached?

0 Borisav Maksimovic over 5 years ago in reply to Michael Tan

Prodigy 30 points

We are monitoring SDA_A (pin 3), that is 3V3 side of I2C level shifter. Expected values are either 0V or 3V3, but we observe level of about 1.5V as the image shows. If HDMI cable to LCD is removed, this behavior stops, I2C data levels are correct, measured at 3V3 side, pin 3.

Here is picture of both, 3V3 and 5V side when I2C is active and LCD connecte. THe question is, what causes this 1.5V levels at Channel 1