Radio and navigation module, function - GF82.61-P-4109-04GI
Processing button actuations
The control buttons and switches on the function keypad on the radio and navigation module (A2/56) are read in via the I/O ports of the microcontroller and transferred to the central processor. Depending on the system function the button actuations are processed in the central processor or relayed to the other system components via the digital data bus ( D2B ) in form of a data telegram.
Graphic preparation and image output
The graphics subsystem handles the preparation and output of the operating displays. The operating displays are output internally to the display by the graphic subsystem via the RGB output ( R =red, G =green, B =blue).
The RGB signal contains information and amplitudes of the three basic colors R ed, G reen and B lue as well as a synchronization signal. The electronic control in the display unit evaluates the RGB signal and actuates the individual pixels line by line according to color and intensity.
A horizontal synchronization pulse is output at the end of each line. The electronic circuitry of the display unit then starts the next line. After reaching the last line on the display, a vertical synchronization pulse is output and the electronic circuitry starts again with the first line.
Audio signal output
The audio signals from the various sources (CD, voice output for route guidance, ...) are processed by the radio and navigation module (A2/ 56) and amplified before output over the vehicle loudspeakers . On vehicles with sound system (code 810) final amplification of the audio signals is accomplished by the sound amplifier (A2/13) . For this purpose audio source data is transmitted to the sound amplifier (A2/13) via the digital data bus ( D2B ).
Diagnosis interface (K bus) and D2B component error management
During the radio and navigation module (A2/56) mode the system stores all errors which occur in the non-volatile memory. These errors can then be read out on the diagnostic interface (K bus) with Star diagnosis . Output of the errors on the display unit is not possible.
Error management also includes components connected to the digital data bus ( D2B ).
Each D2B component has its own DTC memory . The errors are transmitted to the radio and navigation module (A2/56) via the digital data bus (D2B) on request by STAR diagnosis and can then be read out with the diagnostic interface.
Navigation processor and GPS control module
The navigation processor is the central component of the radio and navigation module (A2/56) . It is integrated into the radio and navigation module (A2/56) and calculates the location and vehicle route from the incoming signals after entering the route.
The GPS control module is a part of the navigation processor. It evaluates the satellite signals distributed by the CTEL/GPS roof antenna (A2/49) and the CTEL and GPS antenna splitter (A2/57) and calculates with this information the vehicle position.
CD-ROM and CD drive
With the aid of the navigation CD drive it is possible to read data from the special navigation CD or play audio CD's or play .
The following is stored on the navigation CD-ROM :
- Program data for execution in navigation processor
- Voice data for voice output
- Map data.
The digitized map area on the CD-ROM contains towns, cities, streets, intersections and their attributes (e.g.: one-way streets, turn prohibitions, ...). It does not contain information about company and private ground, farms, housing estates and agricultural roads.
Gyrosensor
The gyrosensor determines the direction change of the vehicle. It is installed in the navigation processor . Calibration is not required.