Mhhhhhh,

I think reading the 5 signals one after the other can't work like expected ...

signal n+1 begins ~ 15 ns ( yes ... NANO seconds ) past signal n ends ...
Pbp cannot follow that !!! ( verified ... need time to change input pin: 4-6 µs.) and we must wait for the following signals burst.

So, @ 4 Mhz the default timeout is 650 ms ...

here we have :

2 + 27 + 27 + 27 + 27 + 5 x 2ms ( maxi ) ... 120 ms per loop ... ( W/a 40 Hz frame )

The truth is elsewhere ...

we must also verify pulses come in the same order as the inputs are connected ...

I already have realised that (with 4 channels ...) and it can be done with a PULSIN - RCTIME - RCTIME - RCTIME - RCTIME sequence ...

My Application is a 4 channel ... Failsafe. WORKING

Alain