I have two slaves on the I2C bus. Before, both master and slaves used the same power source (2.8V), and the I2C bus works fine.
Today, I changed the master to another power source (3.3V), keep the two slaves on 2.8V. Two pull up resistor are 4.7kohm, connected to 2.8V. Now my I2C bus doesn't work at all.
Is there anything else I have to do, to make this change? Do I need to change something in my code? I would appreciate any advice.