I have 4 UNOs and 1 Mega2560 in an I2C bus. I setup 20x4 and 16x4 I2C LCD displays
1.) Master to Slave: I send an x value 1 to 6 to the 5 devices.
Slave 1: LED 13 on x = 1
Slave 2: LED 13 on x = 2
2560 : LED 13 on x = 3
Slave 3 LED 13 on x = 4
Slave 4: LED 13 on x = 5
All LED 13 on x = 6, x resets to 0. It has a 7 segment LED with SN74HC595 to display 1-6
What I want to do next
2.) Slave to Master
I want to put a photo resistor on each slave. Setup a 4 x 2 array, First column the slave number, second column A0 reading 0 to 1000. Send it to the master that can display each one on the 16x2 I2C LCD.
I have been reading Ardiuno books and can't find much on I2C. It is possible to send and receive on the I2C bus?