Good morning all,
Luke was absolutely correct (as usual
), it did turn out to be something simple. Using the ibus2pwm example program from the IBusBM library I tried to see if the serial port was seeing anything at all from the receiver and it wasn't.
Tried a few other things and nothing. Did some more googling (and I had already done quite a bit before but not found this) and discovered a comment on this forum (
https://www.rcgroups.com/forums/showthread.php?2792377-FS-A8S-help) complaining that to switch the FS-A8S receiver from the default ibus to sbus you had to press and hold the bind button for 2 seconds and it wouldn't remember it (rendering sbus a bit useless).
This is in addition to setting the output mode on the transmitter (which was already ibus).
In my initial attempts to get things working I had tried a couple of times to rebind the receiver without any obvious success but it looks like in attempting to do that while the receiver had power (which isn't the process for binding anyway) I must have switched it to sbus output and it looks like they fixed it's ability to remember the setting. With the transmitter set to ibus and not having the required reversing circuitry needed for sbus connections nothing was getting through.
Pressing and holding the bind button for 2 seconds (while powered and bound to the transmitter) it suddenly started spouting serial data out! Woohoo! I now have 10 channels in Op-Config to play with.
The receiver came with the transmitter and the manual for the transmitter doesn't contain any information about the receiver at all so knowing you have to actually do something on the receiver to switch between the modes is voodoo at best.
Sorted...