Hello Andre, Byron et all,

Andre says:
>>I2C is kind of different it will wait until the bus gets free
>>Do you know there rs485 mostly are used ? is there any chip to make
>>I2C work for long distance ?

Byron says:
> Also be very very aware that EIA485 (RS means recommended standard, EIA is
> a actual standard) doesn't have any data link layer, so any communications
> protocol you want to use you'll have to implement yourself.

    actually that means you *can* use I2C (or better, a variation of it) to
implement long distance communication. It's not that dificult and requires 4
wires (plus ground) for the communication.

    Just use 75176's (or other 485 driver/receiver) to carry the I2C
signals. The clock will always walk from the master to the slaves. The data
line is bidirectional, so you'll have to tie the I2C-DATA signal on the PIC
to the RX and TX pins on the 75176 and use another PIC pin to select 75176
TX/RX.

    Best regards,

    Brusque

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Edson Brusque                 C.I.Tronics Lighting Designers Ltda
Researcher and Developer               Blumenau  -  SC  -  Brazil
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