GF82.85-P-3114-08RA Operating, Display and Control Module, Function
GF82.85-P-3114-08RA Operating, Display And Control Module, Function
- with CODE (352) COMAND operating and display
- except CODE (491) USA version
- except CODE (498) Japan version
Processing buttons pressed
The control buttons and switches on the function keypad on the COMAND operating, display and control module (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 transmitted to the system components via the bus system (Digital Data Bus (D2B), CAN-B or RB-CAN) in the form of a data telegram.
Preparation of graphics and output to monitor
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 RGB output (R=red, G=green, B=blue).
The RGB signal contains the information and amplitudes of the three basic colors of red, green and blue, plus a synchronization signal.
The electronic circuitry in the display unit evaluates the RGB signal and controls the individual display dots line by line in terms of color and intensity. A horizontal synchronization pulse occurs at the end of each line. The electronic circuitry of the display unit then starts the next line. After reaching the last line of the display, the vertical synchronization pulse is given and the electronic circuitry starts the first line again.
The output of audio signals from the various sources (CD, voice output for route guidance, etc.) is processed by the COMAND operating, display and control module (A40/3) and amplified before output via the vehicle speaker.
If the vehicle is equipped with a sound system (code 810) the final amplification of the audio signals is carried out by the sound amplifier (A2/13). For this purpose, the audio source data is digitally transferred to the sound amplifier (A2/13).
Info menu
It is possible to move directly to the info menu with the "i-key". This functionality can be selected independent of source (e. g. from the telephone or radio menu). A return is made to the screen from which the info was selected, by means of the Return key. If the mode "Point" was selected in the Info menu, the system switches to the screen preceding the Info menu when the Return key is pressed.
CD-ROM and CD-ROM drive
With the aid of the integrated CD drive data can be read from the special navigation CD or Audio CD's can be played. The navigation CD-ROM contains:
^ Program data for execution in navigation processor
^ Voice data for voice output
^ Map data.
On-Board diagnosis/display
The following functions are included under Info
^ Warm start (operating state)
^ Battery Voltage: e.g. 13.21 V (battery voltage)
^ GPS Number position (available number and position of satellites)
^ Direction: forward/reverse (direction of travel)
^ Speed: km/h mph (vehicle speed)
Diagnostic interface (K bus) and error management for D2B components
During COMAND operation, the system stores all errors occurring in a non-volatile memory. They can read out via the diagnostic interface (K-line) with the STAR diagnosis tool. Output of the errors on the display unit is not possible. The COMAND fault management comprises the components connected to the D2B bus. Each D2B component has its own DTC memory. Upon request from the Star-Diagnosis the faults are transferred to the COMAND operating, display and control module (A40/3) via the D2B and are read out.
Navigation processor and GPS control module
The navigation processor is the central component of the COMAND navigation system. It is integrated into the COMAND operating, display and control module (A40/3) and calculates the vehicle location from the signals received and the vehicle route after the destination is entered. The GPS control module 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. 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.
Note in Navi-CD screen:
"Please insert navigation CD, type DX"
This message is intended to ensure that the customer procures the right CD.
The map area digitized on the CD ROM includes: Villages, towns, roads, crossings and their attributes (e. g.: one-way streets, turn prohibitions, ...). Not included are: for example company and private premises, farms, small settlements and tracks across fields
Gyrosensor
The gyrosensor determines vehicle direction changes. It is installed in the navigation processor. No calibration is required.
Traffic data memory
The integrated traffic data memory receives the traffic messages either over the D2B (in TCS mode) or internally from the radio tuner (in TMC mode).
The data is stored for max. 30 min even during the COMAND shut- off delay time in the traffic data memory (up to 100 messages).
The traffic data memory decodes the messages and transmits them to the navigation processor as required. For synchronization tasks the traffic data recorder requires an up-to-date "location list" from the navigation processor.
The monitoring points that are needed to control the road network (e. g. freeway exits) are uniquely numbered in the "Location List". The "Location list" is stored on the CD-ROM When required, (e. g. when CD-ROM changed), it is automatically loaded into the nonvolatile traffic data memory by the navigation processor.