Help in I2C understanding

Community General Discussion
1

i have a development board.
i want use DCMI (camera interface) with this board.

unfortunately there is an AT24C02 E2prom mounted on board which its SDA pin is connected to the same pin used in DCMI-connection (VSYNC).

i checked datasheet but i am not very perfect in reading datasheet's analog sections.
i am to write this question as a double check to be sure there is no problem with connecting my camera like this.

i guess AT24C02's SDA does not shorted to GND and will not drain current (less than 5μA) when VSYNC line is high

Capture2

2

The SDA and SCL are not a ChipSelect or Enable signal. Together they make the I2C bus.

A falling edge of SDA starts the I2C communication, so the most safe situation is when SDA stays high. SCL can be anything as long as SDA stays high.

Does SCL stay high ?
When SCL stays high, then the EEPROM does not detect its I2C address, so it will never activate its SDA pin.
If there is noise on SCL and SDA becomes low now and then, then it might detect its I2C address with help of the noise.

3

Nick Gammon's I2C page

4

A good guide, IMO:

https://hackaday.com/2016/07/19/what-could-go-wrong-i2c-edition/