[wcfung]

I have 4 Revo, all flashed with Ardupilot firmware (Arduplane and Arducopter). Since the Flex port and Main port are occupied by GPS and OSD respectively, there is no port for telemetry radio. So I looked up the
FlexiIO pinout/Functions paragraph under Revo Configuration in Wiki manual.
I have difficulty understanding that table. Anyway, I tried connecting my telem radio as follows :--
 Telem Rx -- Yellow wire of Revo RC In
 Telem Tx -- Gree wire of Revo RC In.
 + and - power connected as usual.
It did not work, though the telem radio pair lock, but no packet sent or received.
Could anyone shed some light on what's wrong, as the FlexiIO  pinout table clearly shows yellow and green wires are for telemetry ?

Assuming the above wiring works, but the yellow wire is the PPM output from the receiver to Revo, it can't do 2 jobs at the same time. Pls advise.

Another question is : why the PPM output signal is the yellow wire of the RC In ? I tried all other wires of the RC in, they do not accept PPM.

Thank you.

[TheOtherCliff]

Different firmware can include or leave out features, or put them on different pins.  You are using Ardupilot.  I don't even know if Ardupilot allows FlexiIO to be used this way.  It sounds like you have already found a wire conflict with doing this.

You should ask on an Ardupilot forum.    This is a bit like asking Linux people to help you with a Microsoft Windows problem.

[[email protected]]

I have looked at using Revo with Arducopter but the the features available are so limited so I gave up the thought. You will find info about the serial ports here https://ardupilot.org/copter/docs/common-openpilot-revo-mini.html which says there are only two serial ports available and if you need I2C one of those will be taken. The hwdef file confirms this, see this link https://github.com/ArduPilot/ardupilot/blob/master/libraries/AP_HAL_ChibiOS/hwdef/revo-mini/hwdef.dat

As OPLink is not supported the limitations gives a very basic functionality.

Any questions about Ardupilot/Arducopter should of course be asked in those forums as TheOtherCliff already has answered.

[TheOtherCliff]

... info about the (Arducopter) serial ports ... says there are only two serial ports available and if you need I2C one of those will be taken.

Just an FYI:  That is a hardware limitation in Revo's STM F4 microprocessor, so it is true of (probably) all firmwares.  I say "probably" because it may be possible to code I2C communications in software just like it is possible to make a car with 5 wheels, but it isn't worth it.