User Manual

ManualsBrandsFrSky ManualsHobbyDJT 2.4Ghz Combo Pack for JR w/ Telemetry Module & V8FR-II RX

Details of my modification to a Flysky 9x transmitter for FrSky telemetry.

By Mike Blandford (12 Jun 2011).

First the module.

I am using the FrSky DJT module.

I have used the two unused pins in the module so I do not have any external wiring or holes in the

case.

The circuit diagram of my implementation is shown in Figure 1. As with all serial communications,

care has to be taken with the names transmit (Txd) and receive (Rxd). Often the Rxd of one device

needs to connect to the Txd of another device. This may be seen on the circuit where the Txd of the

DJT module is connected to a receive input of the MAX232 device.

Internal to the DJT module, resistor R1 allows a PC to be connected to the external four pin

connector. The PC serial output will override the 9X signal, but both the PC and the 9X will receive

the data sent by the DJT module.

A picture of my wiring inside the DJT module is shown in Figure 2. The resistor from the Rxd pin

Figure 1

Summary of content (3 pages)

PAGE 1
Details of my modification to a Flysky 9x transmitter for FrSky telemetry. By Mike Blandford (12 Jun 2011). First the module. I am using the FrSky DJT module. I have used the two unused pins in the module so I do not have any external wiring or holes in the case. The circuit diagram of my implementation is shown in Figure 1. As with all serial communications, care has to be taken with the names transmit (Txd) and receive (Rxd). Often the Rxd of one device needs to connect to the Txd of another device.
PAGE 2
has sleeving over the bare wire to ensure it does not short to anything else. The wire from the Txd pin is kynar, a single strand insulated wire. Stranded wire is not advisable as it is very easy to allow a strand to short to an adjacent pin. At the four pin, external connector the wires are wrapped round the pin close to the circuit board and then soldered. These pins a sufficiently long that a mating connector will still fit when the wires have been soldered in place.
PAGE 3
Figure 3 Finally the processor board. This was modified as described in http://code.google.com/p/gruvin9x/wiki/FrskyInterfacing with two, surface mount resistors being removed to allow the serial connections to be made to the ATMEGA64A, and two currently unused pins wired via 220 ohm resistors to to replace the signals disconnected by removing the resistors, see Figure 4. Not shown is resistor R2 on the circuit. This is wired in-line on the white wire from the servo connector the the processor board.