When the etpu channel is used as the input capture channel, there is an intermediate value in the process of high level to low level. The figure shows the waveform traced by Lauterbach, and there is also a gif. I would like to ask whether this is related to the timeout detection of etpu itself.
Are you using the IC, PPA, or some other standard function to perform your input capture and measurement? The standard IC function does not have any timeout or intermediate sampling mechanism, whereas the PPA function (for example) does have a sample time parameter and will update the accumulated pulse time at intervals. If you are using a standard eTPU function and can tell us which one, we can probably provide you more information on the behavior you are seeing.
I am not sure about the configuration of our etpu module at present, but I just want to know the timeout logic of etpu in MPC5634. I would like to ask whether timeout detection only exists in low level detection, but not in high level detection.
There is no concept of default timeout in the eTPU - it all depends upon how the device is programmed as to whether there is any kind of timeout detection, and if so, the duration and triggering details. I suppose at a higher-level the host processor could also perform some kind of timeout mechanism on top of the eTPU processing. In any case, I think the actual code in use would need to be examined in order to explain the images you posted.