(5)
 DU Mechanical unit

 The mechanical unit consits of:
 -
a structure which ensures the mechanical strength of the DU and holds in place all the subassemblies

 -
a cover which ensures the protection of the subassemblies and the

 air tightness of the DU (reduction of the ventilation air leaks). The mechanical unit ensures the ventilation air flow and the dispersion of heat. The several subassemblies are housed in the mechanical unit, they include:
 -
the screen and LAM assembly

 -
the BLM assembly

 -
the PSM assembly

 -
the PPM assembly

 -
the GPM assembly

 -
the VPM assembly

 -
the ICM assembly

 -
the HEATER assembly

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 DMC Components
 Figure 003 
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 (a)
 LAM assembly The LAM assembly includes the screen of 6.25 X 6.25 inches which is a flat surface and the triple matrix. It receives the RGB data and several clocks signals (line, frame, pixel frequency) and continuously displays the RGB pixels. Each pixel is triggered by a row driver (horizontal coordinate) and by a column driver. The column driver are linked to CDB board, and the row drivers are linked to a RDB board. An HEATER device is provided to ensure the proper operation of the matrix, while a temperature sensor ensures the temperature control. Two light sensors just below the screen allow light intensity produced to follow the external lighting conditions.

 (b)
 BLM assembly This assembly provides permanent light to the LCD display. It is composed of an array of lamps powered and managed by a dimming module. The dimming module contains a processor that receives luminance orders from the processing module the PPM, elaborated with brightness orders coming from the DU control knob and the light level information coming from the DU front face sensors. The dimming module generates the relevant order to the lamps.

 (c)
 PSM assembly The PSM assembly provides all the necessary voltages for the DU to operate properly

 (d)
 PPM assembly the PPM assembly manages the I/O interface with the A/C: discrete, analog, A429, A629. It also manages bitmap input using A629 and transfer to the GPM. It performs pre processing of the graphic parameters, and the general LCD management.

 (e)
 GPM assembly The GPM assembly generates the image to be displayed. It is composed of two identical synchronized channels working in parallel, each one dedicated to the generation of one image column over two. The graphic CPU functions are performed by software. The code and data of these two processors are stored in the graphic memories. They allow to execute the software program. The image generation function is divided in the following subfunctions: symbology pixel generation WXR pixel generation Bitmap pixel generation MGM memories management mixing

 -symbomogy pixel generation
R 1EFF : 401-499, 1 31-63-00Page 10 1 1 Config-2 Aug 01/05 1 1 1CES 1 Each graphic CPU reads data provided by the processing module in its graphic memory and generates the associated symbology.

 -WXR pixel generation A453 input is collected by each MGM, which writes the data in the graphic memories. Then the CPUs read, processes, write them in secondary graphic memories before their transfer to the WXR part of the MGM memory
 -Bit map pixel generation Bitmap data are selected from the mailbox of the A629 controller, then written in graphic memories, to be transfered in the bitmap part of the MGM memory.
 -MGM memory management Each MGM memory is composed of two memory modules (double page frame buffer) cyclically performing writing or reading/erasing tasks. For symbology, each graphic CPU writes the generated pixels in the write page. At the end of the writing(end of LCD cycle), it sends an order of permutation to its MGM. At the same time, each MGM reads the generated pixels in the read page , in order to mix them, and then erase them. It permutes the two pages, as soon as it receives the order from the graphic CPU and the status of the other MGM (ready for permutation). For WXR and bitmap the process is slower, and pixels are written in the two pages in order for MGM to read them, whatever the status of the considered page towards the symbology (writing or reading).
 -Mixing The mixing is performed by the MGM, which manages the following inputs: symbology (highest priority) WXR bitmap real time video (lowest priority) The symbology, WXR and bitmap pixels are read by the MGM in its memory (read page). Video pixels, processed by VPM, are directly mixed by the MGM (with video DU) . The resulting RGB data (MGM output) of each graphic channel are mutiplexed and sent to the LAM assembly. (Ref. Fig. 004)
　
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