I added a 3 position switch to my Futaba transmitter. I have added the instructions to the wiki here:
http://paparazzi.enac.fr/wiki/index.php/Other_Hardware#Futaba_T6EXAP
I wanted to add the switch to channel 5, but channel 5 does not appear to have an ADC attached to it. Each channel, and the Dual Rate and Trainer switch is connected to a BU4051BCF IC.
From the datasheet: "The BU4051BC, BU4051BCF and BU4051BCFV are analog multiplexers / demultiplexers which use three-input digi-tal signals for control via an 8-channel analog switch. These products feature high on / off output voltage ratio and low crosstalk between analog switches."
As part of the process of determining if it is possible to connect the 3 position switch to channel 5, I documented the connections to the 4051 IC. I have uploaded that diagram to the wiki in the hope that it may prove useful to someone else.
http://paparazzi.enac.fr/wiki/index.php/Image:BU4051BCFchipConnections.JPGCory
