Other Parts Discussed in Thread: TCA9511A, ISO1540, TMS320F28386D,
On our test setup, we have the following summarized schematic:
It doesn't show the routing length or the different connectors, basically the board (left part) is plugged onto the test tray (right part) and on the test tray the two sides are connected through routed wires and through a set of 2 connectors with an he10-like cable assembly (the two parts can be interlinked or not depending on our tests needs).
We have that schematic twice as our tested board has two channels.
On the first channel, it worked like a charm, however on our second one it does not as you can see from the following screenshots (don't pay attention to the label we forgot to remove them) which are taken in between the TCA9511A and the ISO1540:
When zooming, it seems the acknowledge tries to goes high but can't:
If we let the oscilloscope continue, we see spurious event where the signal tries to go high (maybe to send the acknowledge):
Note that in the above screenshots, we changed the 10k pull-ups on the ISO1540 to 1k as we thought that could be the problem as we were having high resistor values compared to the datasheet.
It only changed the level of the spikes from about 1V to about 2V (it would have been odd if it fixed the issue as we see the problem on the other side of the isolator).
I read on another post that the ISO1540 was using SVo and that it wasn't compatible with another TCAxxxxx device but the TCA9511A datasheet doesn't speak about SVo, and moreover I don't see why it works for one channel and not the other considering I checked the schematic and I see no issue nor any discprencies.