Hi, I am having a pulse-width trigger problem as well, with channel D on a Pico 3405A.
If I use the onboard signal generator maxed at a 2V 1 MHz square wave fed into channel A, I can see the triggering stop if I increase the pulse width beyond 500ns. Just fine.
Unfortunately, I am trying to observe a faster signal on channel D, and it only triggers when the pulse width is set to 0 (zero).
I am trying to observe a serial binary signal which is sometimes a single high bit, and sometimes two high bits in a row, operating at around 3 MHz. In other words, sometimes the pulse is one clock cycle (about 300 ns), and sometimes it is two cycles (about 600 ns). Here are some images to help explain.
First there is short_pulse.png, which shows the short pulse of about 300 ns.
Then there is long_pulse.png, showing the longer pulse, about 600 ns.
Finally, there is no_trigger_4ns.png, showing how the trigger doesn't occur even with a "greater than 4ns" setting.
I expect that I should be able to set to pulse width triggering around "greater than 500 ns" and the trigger occur only on the longer pulse. Unfortunately the trigger never occurs. There is a lot of ringing on the signal, but that ringing is all above the trigger threshold and shouldn't be a problem. I also tried a window pulse width, setting "dwell inside" to cover the entire ringing amplitude, and it doesn't work either. Is help available for this issue?