Hello,
I've connect two SSD1306 to Arduino. They are both connected using I2C and answer the same I2C address.
During development they work fine, everything I sent to the OLED was display on both screen at the same time.
Now, when I connect the Arduino to external power source, without downloading the code to it, it only initialize and display on one screen while the other show snow (black and white dots scatter).
If I connect the Arduino to USB, without downloading the code, the result is the same and only one screen works. If I open the serial monitor it seem to reset the Arduino and then both of the screens work together.
How can I cause both of the screens to work together?
Both displays with the same address is different. I've never heard of i2c devices runnning in parallel. There will most likely be all kinds of communication problem talking to the micro. If you can give one display a different address then all will be good.
I've connect SA0 of one screen to the ground which change it address from 0x3D to 0x3C.
They still share a single RESET pin - do you think this is a problem?
The result of using two different addresses is still the same. When I download software from Arduino editor both screen works. When I disconnect and connect the Arudino to power source only one screen works.
The strange thing is that after I disconnect and connect the Arduino to my USB, only one screen works and the other show snow.
When I open the Serial Monitor window the Ardino reset and when start again both screen works - all the time.