Operating, display unit with control unit, function - GF82.85-P-3114-08PM

Processing button actuations 

The control buttons and switches on the function keypad on the COMAND operating, display and control unit (A40/3) are read in via the microcontroller I/O ports and transferred to the central processor. Depending on the system function, the button actuations are processed in the central processor or transferred to other system components via the Media Oriented Systems Transport (MOST) and, Controller Area Network bus Class B (interior compartment), in the form of a data telegram.

Graphic editing and image output 

The video subsystem takes over editing and output of the control displays. The operating masks are internally output to the display by the graphics subsystem via the FBAS output.

The information and amplitudes of the 3 primary colors red, green and blue as well as a synchronization signal are included in the FBAS signal.

The electronic circuitry in the display unit evaluates the FBAS signal and controls the individual display dots line by line in terms of color and intensity. The end of each line is followed by a pulse, which synchronizes the horizontal picture signal. The electronic circuitry of the display unit then starts the next line. Upon reaching the last line a pulse is received, which synchronizes the vertical picture signal, thus causing the electronic circuitry to start the 1st line again.

Audio signal output 

The audio signals from the various sources (CD, navigation voice output, etc.) are prepared by the COMAND operating, display and control unit (A40/3n1) and amplified before being output via the vehicle speakers. For code (810) sound system, final amplification of the audio signals is carried out by the sound amplifier (A2/13). For this purpose, the audio source data are digitally transferred to the sound amplifier (A2/13).

Info menu 

Using the "i" or "INF keys" takes you straight to the information menu. This functionality can be selected independently of source (e.g. from the telephone or radio menu). The screen from which the information was selected can be returned to by means of the "Return" key. If the Mode option was selected in the Information menu, the system switches to the screen preceding the Information menu when the "Return" key is pressed.

Diagnosis interface (K-line) and error management 

While the COMAND operating, display and control unit (A40/3) is active, the system stores all faults that occur in the non-volatile memory. These can be read out via the data link connector (X11/4) with the aid of STAR DIAGNOSIS. Output of the errors on the display unit is not possible. The diagnosis also includes the components connected to the MOST ring. Each MOST component has its own fault memory. When requested, the errors are transmitted by STAR DIAGNOSIS over the Media Oriented System Transport (MOST) to the COMAND operating, display and control unit (A40/3) where they can then be read out.

Navigation processor and GPS control unit. 

The navigation processor is the central component of the navigation system. It is integrated in the COMAND operating, display and control unit (A40/3) and calculates the location of the vehicle from the incoming signals. It also calculates the vehicle's route after the destination has been entered. The GPS control unit is part of the navigation processor. It evaluates the satellite signals coming from the GPS antenna (A2/23) and calculates the vehicle position from this information.

Position finding 

At least 4 satellites are required for dead reckoning, 3 satellites are sufficient for other calculations. If these requirements for dead reckoning do not exist, only the number of satellites appears in the display.

DVD and DVD disk drive 

With the aid of the integrated multi-standard drive, data can be read from the special navigation DVD or audio CDs can be played.

The following data are located on the Navigation DVD:

• Program data for execution in navigation processor
• Voice data for voice output
• Map data.

Note in Navi-CD screen:

"Please insert Navigation CD, type DX"

This notice is intended to ensure that the customer inserts the correct DVD.

The digitized map area on the DVD contains towns, cities, streets, intersections and their attributes (e.g.: one-way streets, turn prohibitions). It does not contain information about company and private land, farms, housing estates and paths.

The traffic data memory 

The integrated traffic data recorder receives the traffic messages either via Media Oriented System Transport (MOST) or internally from the radio tuner.

The data are stored for a maximum of 30 min in the traffic data recorder, including during the run-on time of the COMAND operating, display and control unit (A40/3) (up to 100 messages). The traffic data memory decodes the messages and transmits them to the navigation processor as required. For synchronization, the traffic data recorder requires a current "location list" from the navigation processor. The monitoring points for checking the road network (e.g. freeway exit) are defined by unique numbers in this list. The location list is stored on the DVD. It is automatically loaded (e.g. if DVD is changed) from the navigation processor into the traffic data recorder.

Gyrosensor 

The gyrosensor determines vehicle direction changes. It is installed in the navigation processor. Calibration is not required.