i2c advaned addressing
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Synopsis
- The i2c bus is controlled by an i2c bus master. (Not to be confused with a 1-wire bus master like the DS2482).
- The i2c bus master is handled by the operating system, and given a port address (like /dev/i2c-0 /dev/i2c-1, ...)
- Each i2c bus, in turn, can hold several i2c devices (i2c slaves), each with a (hardware selected) address like 0x18, 0x19, ...
- It is possible, in OWFS, to specify an exact i2c bus and i2c slave device address.
- It is also possible to select any or all i2c slaves.
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Simple mode (just the port)
- In the simple mode, only the i2c port is specified and the FIRST DS2482 will be chosen.
- Syntax:
-d /dev/i2c-0
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Advanced mode
All advanced addressing options use
--i2c
rather than
-d
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port
Specifying just the port is the equivalent of simple mode -- the first DS2482 on that i2c bus will be selected
--i2c=/dev/i2c-0 # First DS2482 on bus 0
If no port is given, OWFS will scan through the first 99 i2c buses and select the first match. So
--i2c # will match the first DSS2482 found
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address
A specific i2c address can be specified using the syntax:
--i2c=/dev/i2c-0:0 # Bus 0, Address 0 (0x18)
or
--ic2=/dev/i2c-1:2 # Bus 1, Address 2 (0x1A)
If no address is specified, the first matching DS2482 will be chosen.
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ALL
The wildcard ALL can be used as a port or address and all matching DS2482's will be used
--i2c=/dev/i2c-2:ALL # All DS2482 on bus 2
and
--i2c=ALL:ALL # All DS2482 on all i2c buses
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Address table
| Pins selectedin chip | command line address |
i2c slave address |
DS2482-100 | DS2482-101 | DS2482-800 |
|---|---|---|---|---|---|
| 0 | 0 | 0x18 | yes | yes | yes |
| 1 | 1 | 0x19 | yes | yes | yes |
| 2 | 2 | 0x1A | yes | yes | yes |
| 3 | 3 | 0x1B | yes | yes | yes |
| 4 | 4 | 0x1C | no | no | yes |
| 5 | 5 | 0x1D | no | no | yes |
| 6 | 6 | 0x1E | no | no | yes |
| 7 | 7 | 0x1F | no | no | yes |
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