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Eliminating Conflicts between ROT and PIUSV

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wvhn edited this page Jun 21, 2016 · 7 revisions

I use the PIUSV+ as an uninterruptable power supply and the ROT as KNX bus interface. Unfortunately, both devices use the same i2c address 0x18. PIUSV+ transmits the status information via this address while ROT has the Onewire interface mapped to it. When writing about ROT I assume that the alternative PIGATOR Onewire module might have the same problem.

With both devices installed, status information of the PIUSV+ is faulty. So the deamon immediately starts the shutdown countdown after booting.

Both devices have their addresses hard-wired on the board. Well - not the best way of engineering. Two jumpers for address configuration would have solved the problem easily.

Changing the Address of the ROT Onewire Module

Look for the DS2482-100 Chip on the module. You will find Pins 7 (AD1) and 8 (AD0) connected to GROUND. Carefully lift Pin 8 from the board using a soldering iron. Then connect this Pin to VCC (Pin 1).

ROT
DS2482

The detection on the i2C interface delivers

admin@smarthome:/usr/smarthome$ sudo i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- 18 19 -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: 50 51 52 53 54 55 56 57 -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
  • 0x18 is the PIUSV+
  • 0x19 is the new address of the ROT Onewire interface
  • 0x50 - 57 represent the EEPROM on the ROT module
  • 0x68 addresses the real time clock on the ROT module

Now, the PIUSV+ works correctly. I have not yet configured Onewire on my Pi but I'm planning to test it and give an explanation here, how to set up the new address correctly for smarthome.

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