Other Parts Discussed in Thread: ISO7741
I have a u-Controller which communicates with several slaves using SPI-bus. The slaves are all isolated from u-Controller and each other, each of them in its own isolation plane.
The problem is that the return data-line need to be common (going to MISO). Connecting the isolators outputs together causes very strange voltage level of the signal and some non-recognizable data on it.
I was trying to separate the outputs using a Schottky diode on each of them, connecting the cathodes together and providing it this way to the MISO. Still not working - the cathode is always high level even I am trying to pull it down by resistor. Strangely the signals on the anodes are all exactly as they should be - do not understand why the cathode is permanently high logical level.
Any help would be highly appreciated!