Operation CHARM: Car repair manuals for everyone.

GF82.61-P-4109-04A Radio and Navigation Module, Function



GF82.61-P-4109-04A Radio And Navigation Module, Function
- with CODE (353) Audio 30 APS


Processing key signals
The controls on the radio (A2) are read in via I/O ports of the microcontroller and made available to the central computer. Depending on the system function the button operations are processed further in the central computer or conveyed via the Digital Data Bus (D2B) or interior CAN (CAN B) in the form of a data telegram to the system components involved (e.g. CD changer).

Display
The display of the radios (A2) has 197 x 32 pixels. Texts are displayed in 3 lines.
After particular functions are called (e.g. navigation), the bottom line shows a variable inscription for the row of buttons underneath (multifunction buttons). As a result the system can be operated very conveniently with a few buttons, as the function which is activated when the button is operated, is shown in plain text (e.g. LANG, ITEM, DYN, CLOCK etc.).

Audio signal output
The audio signals of the various sources (CD, voice output for navigation etc.) are processed by the radio (A2) and amplified before output by the vehicle speakers.

On models 168, 170, 208 and 210 with the sound system (code 810) the audio signals are finally amplified by the amplifier for the sound system (N40/3). For this, the audio source data (low-frequency signals) are transmitted to the amplifier for the sound system (N40/3) via separate lines.

On models 163 and 209 the final amplification of the audio signal is performed by the sound amplifier (A2/13). All the data are transmitted via the D2B.

Audio mute
An incoming phone call activates the audio mute function (a separate signal input exists on the radio (A2) for this). When the audio mute function is activated, the current audio source (e.g. radio) is muted automatically.

Navigation processor, GPS control module and gyrosensor
The navigation processor is the central component of the navigation system.

It is integrated into the radio (A2) and from the incoming signals continuously calculates the location and once the destination is entered calculates the route for navigation. The GPS receiver is integrated into the navigation processor. It evaluates the satellite signals and calculates from them the vehicle position in degrees longitude and latitude. Various GPS antennae are used to receive these signals depending on the vehicle model:
^ Model 163: telephone and GPS roof antenna (A2/49)
^ Models 168, 208.3, 210: GPS antenna (A2/49a2)
^ Models 170, 208.4: GPS rear antenna (A2/23a2)
^ Model 209: GPS antenna (A2/23)

Reception from at least 3 satellites is necessary for exact GPS position calculation. A free view of the sky is required for this purpose.

The integrated gyrosensor continuously senses every change in direction of the vehicle. Evaluation of this data is accomplished by the navigation processor.

Calibration of the gyrosensor is not required.

DVD drive and DVD
The DVD drive of the radio (A2) reads data from the navigation DVD inserted and makes this available to the navigation processor via the data bus inside the device.

Audio CDs can also be played.

The following are located on the navigation DVD:
^ Program data for the navigation computer
^ Voice segments for voice output
^ Map data.

A distinction is made between digitized and non-digitized areas within the DVD map area
^ Villages, towns, roads, intersections and their attributes (e.g. one-way streets, no turns etc.) are recorded in the digitized map area.
^ Included in the non-digitized areas are, for example company/private grounds, farms, small housing estates, tracks across fields and areas between villages. No data is available here.

Diagnosis interface (K-line) and fault management of D2B-components
During operation, the system stores all occurring faults in the nonvolatile memory. It is not possible to output the fault via the display of the radio (A2).

The radio's (A2) fault management also includes the D2B-components connected. For this purpose, each D2B component has its own DTC memory. The faults are transmitted from the corresponding components via the D2B to the radio (A2) and can then be read out via the diagnosis interface