I’m using a Radiomaster TX16S transmitter with a LemonRx DSM receiver to drive a Pololu multiplexer and triggering each side of the multiplexer based on the output of one of the receiver channels. This is for use in an RC plane, so I don’t have 100% controller of the PWM signals coming from the receiver.
I’m going through the learning mode to try and set the trigger pulse width at around 900us. According TX16S, the output when I go through the learning mode is 834us. Normal range when operating for the channel says 998us - 2012us, with a mode switch dropping it down to the 834us level again to trigger the channel swap of the multiplexer. Note there may be some remapping happening to push the actual receiver output into the 1100us - 1900us range. I don’t have anything currently to test the actual pulse width coming out of the receiver channel.
The problem is, the learning mode seems to complete OK, and when I first power all the gear including the multiplexer up, the LED is showing the regular short blink indicating it’s running OK and the master channel is engaged (i.e. multiplexor inactive). I change modes so my receiver channel operates within normal limits, and the LED goes to the long blink, indicating it is active and swapped to the slave channels. However when I swap back to the initial mode again, the multiplexer stays active and I can’t get it to turn off again, unless I re-power the unit.
If the multiplexer was using the default setting of around 1700us for the trigger, I should see it flipping during the normal operation which goes above and below this value, but it doesn’t change.
I’m not sure what else to try. Any suggestions on why it’s fine when first booted, but then won’t reset to inactive once the active has been triggered? Maybe there’s something about the way the threshold is being set that I’m missing, but I’ve been through these instructions Pololu - 9.1. General Configuration Procedure many times and can’t see what I’m doing wrong. Only thing I can think is the pulse reading is not getting the values my receiver should be outputting. I’m not getting the error LEDs about a low value setting, so I’m not sure what value it’s setting the threshold at, but it seems to be outside the range my receiver can supply.