Hi guys, in my project I have 8 arduino standalone configured as slave and I would like to let them to communicate with a duemilanove configured as master; I can send messages from master to each slave but i have problems on receiving informations from slaves to the master. For example I have connected a DS1307 to slave #2 because I didn't know that only the master can drive the rtc, so if I want to send the time given by the rtc to the slave #2 I must ask time to the master at first and then send it to the slave even if the rtc is connected to the pcb with slave #2 and this is not very amazing....
Is possible to make a multimaster solution?
I have also noticed that I2C communication falls if the power of a slave device is turned off, it's normal? Now I'm trying to electrically isolate the scl and sda wires from slaves with some CD4066 and enable them only if the slaves are turned on, hoping that this trick will work.
I apologize with you for my terrible english but I hope you understand what I'm trying to say, I asked first in italian forum but I had no answer.
Greetings from Italy.
A multimaster I2C implementation is possible as I have used one professionally. However I don't think anyone has written the driver code for the arduino to do this.
I have also noticed that I2C communication falls if the power of a slave device is turned off, it's normal?
Yes because the data and clock lines are effectively shorted to ground through the un powered device.
hoping that this trick will work.
Yes it should.
The CD4066 I've used has worked fine