PPM-in is not compatible with Spektrum (and other?) radios

GoogleCodeExporter commented 8 years ago

This is a hardware compatibility issue, not fixable by code (alone).

What steps will reproduce the problem?
1. Use a 'buddy lead' to connect a Spektrum (or other?) brand radio into the 
'trainee' jack on the back of the '9X
2. Got to PAGE 2 in the Set-Up menus 'PPMIN'
3. Note that very little, if anything happens when you move the sticks on the 
trainee (slave) radio.

What is the expected output? What do you see instead?
PPM-in should work

The problem is caused by the '9X expected full 5V-TTL level signal from the 
PPM-in phono jack. But the Spektrum (and others?) radio only makes available a 
capacitively decoupled approx. 1.5V peak-to-peak signal. 

An additional buffer transistor (or external adaptor) will be needed if this is 
to be overcome. If the buffer inverts the signal, a small code change will also 
be required.

Original issue reported on code.google.com by gru...@gmail.com on 26 Dec 2010 at 5:08

GoogleCodeExporter commented 8 years ago

[deleted comment]

GoogleCodeExporter commented 8 years ago

Fixed in Gruvin's 'hacked' Turnigy 9X. See 
http://code.google.com/p/gruvin9x/wiki/PpmIn for details. Circuit mod scheduled 
for inclusion in PCB v3

Original comment by gru...@gmail.com on 27 Dec 2010 at 4:08

GoogleCodeExporter commented 8 years ago

Original comment by gru...@gmail.com on 23 Sep 2011 at 1:52

Changed state: Verified

sylvandb / gruvin9x

PPM-in is not compatible with Spektrum (and other?) radios #15