I2C Slave with a PIC

[Wirecut]

Your tips are pushing me towards the RS485.
The only trouble and not've never used before.

I am somewhat concerned about the protocol to use.

You have to give me a hint where to look to select the protocol that I could use?

Leo

[Ioannis]

If you have used serial RS232, then the RS485 is just the same. Only drivers (chips) are different. And the signal is TTL level from your controller to the RS485 driver.

The RS485 is not a protocol, rather a low level electric specs of the medium. It does not care about how the data will be sent.

So you really have not many concerns on this. Almost Plug and play.

Ioannis

[Wirecut]

In reality the RS232 is designed to connect generally ONLY two devices toghether.

The RS485 have the capability to manage multiple slave and one master.

In my project I have one master and I connect the USART to the RS485 chip and then in daisy chain all the other RS485 chip to the USART's slave. But that means every slave have his proper address, manage receiving, CRC chek etc etc and to do in the best way is needed a protocol.

Googling I have found the SNAP protocol ( http://www.hth.com/snap/ ) that shall be good to be implemented in my solution and have the source code in PBP (old version).

If I do not found a protocol more simple than SNAP, I will study and implement it.

Leo