I need to decode communication between two devices, but I have no information about these devices. All I know is that four wires are needed (GND, VCC and two wires of communication). I suspect that it is I²C communication.
I'm trying to decode it with the oscilloscope decoding tool, but I'm not quite sure about it. I can not identify elements of I²C communication appropriately when I visually check the waveforms.
Looking at the waveforms I made the following assumptions, and maybe someone can help. These were my assumptions:
- Everything leads to believe that the clock is the blue signal and the data is the red signal.
- The clock seems to be inverted because its idle state is not at high level.
- I'm not sure if the data signal is also inverted, but it seems to be.
Are my assumptions correct?
In the last figure, the figure with the number 5 indicated in a circle, and there is a part of the signal. I can not identify the start, ack and stop bits. Can anyone identify these elements just looking at the figure?
[Edited] Some people asked me about the devices that are in the communication. The communication is between a car key and a tool that I'm not allowed to say, but I'm trying to do a reverse engineering on it.