The Flysky iA6 receiver is PWM only receiver. It doesn't even support PPM. It is a low cost and compact receiver for the Flysky i6 Transmitter.
Read the RCGroup user darven that started it here
Read the betaflight PR here.
iBUS Hack
If you know how to solder and compile your own copy of Cleanflight/Betaflight firmwares you can have an iBUS receiver using the FS-iA6. It is very compact once you remove the pins and only uses the iBUS wires.Wiring
Use this versions of the files then recompile.
Read the betaflight PR here.
Alternative
This is just an alternative if you have extra iA6 receivers. The FS-iA6B is the same price as the iA6 and it has ibus/ppm port and can output 10 channels on ibus configuration.