GF82.85-P-3133TXJ Operating and Display Unit With Control Unit, Component Description

GF82.85-P-3133TXJ Operating And Display Unit With Control Unit, Component Description
- with CODE (498) Japan version

Component Identification:

Location
The COMAND operating, display and control unit (A40/3) is installed in the center console.

Task
The COMAND operating, display and control unit (A40/3) controls the following systems:
^ Audio system (radio, Minidisc (MD), audio CD)
^ Navigation system
^ Telephone system
^ CD changer (A2/6)
^ Integrated TV system and video DVD

Design
The following are integrated in the COMAND operating, display and control unit (A40/3):
^ Graphic compatible color liquid crystal display (LCD)
^ Digital versatile disk (DVD) ROM disk drive
^ Minidisc (MD) disk drive
^ Operating unit for control of audio, video, navigation, and telematics functions
^ Central processor
^ Navigation processor
^ Interface to the Media Oriented System Transport (MOST)

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

Graphic editing and image output
The video subsystem takes over editing and output of the control displays. The control displays are output internally by the graphics subsystem via the composite (CVBS) signal input to the display of the COMAND operating, display and control unit (A40/3).

The information and amplitudes of the 3 basic colors red, green and blue as well as a synchronization signal are included in the CVBS signal. The electronic circuitry in the display unit evaluates the CVBS signal and controls the individual display dots line by line in terms of color and intensity. There is a pulse at the end of each line which synchronizes the horizontal video 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 video signal causing the electronic circuitry to start the 1st line again.

Audio signal output
The audio signals from the various sources (CD, voice output for navigation, etc.) are processed by the audio gateway control unit (N93/1) and amplified before being output via the vehicle speakers. The audio signals are pre-amplified in the audio gateway control unit (N93/1) (base version) or amplified by a sound amplifier (model 219.35 with code (810) Sound system) integrated in the audio gateway control unit (N93/1).

Info menu
It is possible to move directly to the info menu with the "INFO" button. This functionality can be selected independently of source (e.g. from the telephone or radio menu). With the "Back" button the user returns to the screen from which the info-menu had been selected.

Diagnostic interface and fault management
While the COMAND operating, display and control unit (A40/3) is active, the system saves all faults that occur in the non-volatile memory. These faults can be read out using STAR DIAGNOSIS via the data link connector (X11/4). It is not possible to output faults via the COMAND operating, display and control unit (A40/3). The diagnosis includes all components of the MOST ring. Each MOST component has its own fault memory. The faults are transmitted by STAR DIAGNOSIS via MOST to the audio gateway control unit (N93/1) as central diagnostic interface upon request and can be read out.

Additional readout in the display
If the requirements for position calculations are not met (for the first position calculation, the reception of at least 4 satellites is required), only the number of satellites received appears in the display of the COMAND operating, display and control unit (A40/3).

DVD and DVD ROM drive
The DVD ROM disk drive of the COMAND operating, display and control unit (A40/3) is used, in addition to playing audio CDs and video DVDs, to load a navigation DVD required by the navigation system.