Here are some details how to use the CAN-bridge to filter the conflicting CAN messages from the RNS-E in an Audi A3 8P, TT 8J and Audi R8 in order to use the FIS-Control.
If the CAN bridge is installed and the ignition is turned on, the cluster will only get the CAN messages from the FIS-Control. The CAN messages from the nav are blocked.
If you do a longer drive with guidance and want to see the directions of the nav on the cluster, you can press and hold the up key of the wiper stalk while you turn on the ignition. Now all messages from the nav are forwarded to the cluster. The FIS-Control will stay inactive until the ignition is turned on the next time.
The CAN bridge has a 9 pin Sub-D connector.
Pin 1 = 12V Battery voltage (terminal 30)
Pin 2 = CAN (low) to nav
Pin 3 = CAN (low) to cluster
Pin 4 = goes to pin 3 (TxD) of the RS-232 (for software update)
Pin 5 = goes to pin 2 (RxD) of the RS-232 (for software update)
Pin 6 = GND and pin 5 (GND) of the RS-232
Pin 7 = CAN (high) to nav
Pin 8 = CAN (high) to cluster
Pin 9 = do not connect
Attached is the firmware for the CAN bridge.
To transfer the software to the CAN bridge, at least pin 1 (12V) and pin 6 (GND) and also the RS-232 to a laptop has to be connected.
Please pay attention that the laptop and CAN bridge share the same ground connection, so connect pin 6 of the bridge also to pin 5 of the RS-232.
Start TeraTerm on the laptop and select the used COM port and select the baudrate 115200 bps (Setup -> Serial port).
Turn on the ignition and select FILE -> SEND FILE and enable the BINARY option. Now send the file delete_firmware_cmd.hex.
If you don't have a CAN bus connected to the CAN bridge yet, you have to do that within 5 seconds after powering the bridge, else it will enter sleep mode.
Now turn off and on the ignition. You will now see the letter C arriving once per second in TeraTerm. This indicates that the CAN bridge is waiting for a new firmware.
Use TeraTerm with FILE -> TRANSFER -> XMODEM -> SEND and select the attached .fw file.
After transfer is finished, turn off the ignition.
Next time you turn on the ignition, you should be able to use the FIS-Control. Please make sure that the selected communication channel in the FIS-Control settings is "Navigation". You may also want to enable the modification "CAN-BRIDGE". This modification will allow to see the output of the nav on the FIS display when the up button of the wiper control stalk is pushed while turning on the ignition.