EP1971977B1 - Display of static symbols on a matrix screen - Google Patents

Abstract

The invention relates to a device and a method for displaying symbols on a matrix screen. Said device comprises means for storing (11) a plurality of static zones (2, 3) of the screen (1) and a plurality of symbols (4, 5) to be displayed in each zone (2, 3), a zone table (12) defining the symbol (4, 5) to be displayed for each zone (2, 3), and means (10) for controlling the display of each point of the matrix according to the symbol (4, 5) retained in the zone table (12) and of the allocation of each point to a given zone (2, 3) determined by the storage means (11). According to the method, in each point of the screen: the zone (2, 3) to which the point belongs is determined by the storage means (11), the symbol (4, 5) to be displayed is determined by the zone table (12), and the display of the point is generated.

Description

The invention relates to a device and a method for displaying symbols on a matrix screen. Many applications require the display of symbols to inform a user. By way of example, mention may be made of billboards of stations or airports, screens of entry gates with digital code, certain equipment of aircraft dashboards and telephony.

In a known manner, dedicated screens comprising predetermined zones are used, each zone comprising one or more segments depending on the symbols that it is desired to display in the zone. For example, displays are known in which each zone has 7 segments and makes it possible to display any number in each zone. Dedicated displays lack flexibility in their use. For example, it is not possible to change the size of a zone and the number of segments it contains without developing a new screen. Moreover, nothing can be displayed in the space between the segments.

To allow an evolution of the definition of the zones while preserving the same physical screen, one can use a matrix screen which is not dedicated by design to a type of frozen display. This type of screen is organized in rows and columns. Each intersection of a line and a column forms a display point. This screen has no predetermined zone. To generate an image on such a screen, a graphical processor-based architecture is used, for example used in technologies developed for micro-computing. This type of architecture is for example described in the document US 4,827,249 . This type of architecture makes it possible to generate moving images and is therefore oversized for displaying symbols. In addition, this architecture is much more complex than that used to control a dedicated screen. It is, therefore, much more expensive, its power consumption is higher and its reliability is lower. It is also constrained by the rapid technological evolution of this type of architecture which disrupts the maintenance in long-term operational condition. Indeed, a few years after the development of an architecture, it is often impossible to supply spare parts.

The invention aims to overcome the problems mentioned above by proposing the use of a matrix screen, that is to say not dedicated, without using an architecture using graphics processor to display symbols.

For this purpose, the subject of the invention is a device for displaying symbols on a matrix screen, according to claim 1.

The storage means advantageously comprise a non-volatile memory such as for example a read-only programmable memory well known in the Anglo-Saxon literature under the name of "PROM". The use of this type of memory makes it easy to change the size of the zones and the different symbols that can be displayed in each zone. It is no longer necessary to develop a new physical screen when developing a new application. Just reprogram or change the non-volatile memory. Numerous types of read-only memories can be used to implement the invention, such as for example electrically programmable dead-memories, erasable read-only memories by means of ultraviolet radiation, programmable read-only memories quickly well known in the literature. Anglo-Saxon under the name "FlashPROM".

The invention also relates to a symbol display method on a matrix screen, according to claim 4.

• la figure 1 représente un exemple d'écran dans lequel des zones ont été définies ;
• la figure 2 représente des symboles affichés sur l'écran de la figure 1 ;
• la figure 3 représente un dispositif conforme à l'invention ;
• la figure 4 représente un exemple de table de zone.

The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, a description illustrated by the attached drawing in which:

• the figure 1 represents an example of a screen in which zones have been defined;
• the figure 2 represents symbols displayed on the screen of the figure 1 ;
• the figure 3 represents a device according to the invention;
• the figure 4 represents an example of a zone table.

For the sake of clarity, the same elements will bear the same references in the different figures.

The figure 1 represents a matrix screen 1 on which two zones 2, 3 and a screen are represented. The contours of zones 2 and 3 are represented in strong lines. A zone according to the invention is a set of points of the matrix in which it is desired to display an image. An area has a fixed location on the screen, hence the static qualifier for the areas defined on the screen. The points of an area may not be contiguous. The different areas can not overlap. In other words, a point on the screen belongs to only one zone.

On the figure 2 , two symbols 4 and 5 are each represented in a zone, respectively 2 and 3.

The wallpaper also forms an area that must also be controlled. For example, all the points forming the wallpaper can be turned off.

The device represented on the figure 3 comprises the screen 1, a central sequencer 10 for controlling the display on the screen 1, storage means 11 of several areas of the screen and several symbols to be displayed in each zone. These storage means advantageously comprise a non-volatile memory connected to the central sequencer 10. By nonvolatile memory is meant a memory that stores the information it contains even in the absence of a power supply. This type of memory is often called a ROM. The central sequencer 10 can be implemented by means of a programmable logic component well known in the English literature under the FPGA name. It is also possible to make this sequencer using discrete components or even by means of a microprocessor. In a preferred variant of the invention, the non-volatile memory is made using a read-only programmable fast memory well known in the English literature under the name FlashPROM.

The device further comprises a zone table 12 also connected to the central sequencer 10. The display of each point of the matrix is defined according to the symbol retained in the zone table 12, the membership to a given area, determined by the memory means 11. The membership of a zone is conditioned by the position of the current point in the matrix of the screen.

1. 1. Déterminer la zone à laquelle le point appartient à l'aide des moyens de mémorisation 11. Cette détermination se fait en fonction de la position du point courant sur la matrice de l'écran 1 et s'effectue par lecture d'une zone des moyens de mémorisation 11 affectée à une correspondance entre point courant et appartenance à une zone.
2. 2. Déterminer le symbole à afficher à l'aide de la table de zone 12, en fonction de la zone d'appartenance du point courant.
3. 3. Générer l'affichage du point.

A display method using the device described above consists for each point of the screen 1 to:

1. 1. Determine the zone to which the point belongs using the memory means 11. This determination is made according to the position of the current point on the matrix of the screen 1 and is performed by reading a zone storage means 11 assigned to a correspondence between current point and zone membership.
2. 2. Determine the symbol to be displayed using the zone table 12, according to the area of membership of the current point.
3. 3. Generate the point display.

Advantageously, the generation of the display of a point is done using the storage means 11 and the storage of each symbol comprises the state of each point of the zone considered. The state of a point is for example turned on or off in the case of a monochrome screen. The state can also set the color of a point in the case of a color screen. More precisely, the address is determined in the storage means 11 where the current point status information, for example on or off, is located, depending on the position of the current point on the matrix of the screen 1 and data in the zone table 12. In other words, the addressing of the storage means is defined by a counter of the points of the matrix screen 1, for example for the least significant bits of the addressing and by the information elements. contained in each line of the zone table (2, 3), for example for the most significant bits of the addressing.

Area table 12 contains the symbol for the area to which the current point belongs. From the symbol read in the zone table 12, the storage means 11 seek the status information of the current point among the possible symbols stored in the storage means 11.

More precisely, the zone table 12 is generated as a function of the image that it is desired to see on the screen 1. The zone table 12 is advantageously stored in a random access memory, for example of well-known random access type. the Anglo-Saxon literature under the name of RAM. In the prior art, to generate an image on a matrix screen, a random access memory is used in which a display information is generated and stored for each point of the screen 1. On the contrary, in the invention, it generates and stores in the RAM zone table 12 which includes only global display information per zone. The invention makes it possible to very clearly reduce the size of the random access memory used for the display on the screen 1.

The figure 4 to better understand the organization of a zone table 12. The table 12 is organized so as to ensure the definition of a symbol to be displayed in a given area.

Advantageously, each zone is identified by a number and the number of the zone to which the current point belongs forms an address 13 of the random access memory and the data 14 of the random access memory associated with the address 13 defines a variation of the symbol of the considered area.

The data 14 of the RAM gives an additional address to find the states of the points to be displayed. This complement of address, associated with a counter, internal to the central sequencer 10, which points to the position of the current point makes it possible to determine the address in storage means 11 where the state information of the current point is located. On the figure 4 zones 2 and 3 are represented in address 13. The data item 14 gives a retained symbol variation for the zone considered. For example, a given 14 5 bits wide, the zone could display Users 2 ⁵ ie 32 different symbols. In fact, since this data item 14 constitutes a complement of address on the one hand and the memory contains a space on the theoretical 32 for the identification of the area of membership on the other hand, in fact there are 31 symbols different by zone. Considering an eight-bit wide memory, the data item 14 contains 3 additional bits making it possible to multiply by eight the number of symbols, therefore in all 248 different possible symbols per zone. These 248 symbols are all small fields of pixels that can take any value and constitute alphabetic characters, numbers or pictograms. It is understood that the zones are independent of each other. The variations of one zone may be different from the variations of another zone. The definition of the symbols is specific to each zone. For example, if the variations of one zone make it possible to display alphabetic characters, another zone can make it possible to display numerical characters or pictograms. After the programming of the read-only memory defining the zones and the different symbols to be displayed in a zone, a symbol of a zone can only be displayed in this zone except of course to be defined a new time in another zone.

• on adresse une première page des moyens de mémorisation 11 à l'aide d'un compteur de position de point de l'écran 1,
• on adresse la table de zone 12 au moyen de la donnée extraite des moyens de mémorisation 11 à l'aide d'un compteur de position de point de l'écran 1,
• on adresse les moyens de mémorisation 11 à l'aide de la donnée extraite de la table de zone 12,
• on définit un état d'affichage du point par la donnée extraite des moyens de mémorisation 11 à l'adresse obtenue par la donnée de la table de zone 12.

More specifically, a display method using the device described above consists in linking and repeating for each point of the screen 1 the following operations:

• a first page of the memory means 11 is addressed by means of a dot position counter of the screen 1,
• the zone table 12 is addressed by means of the data extracted from the storage means 11 by means of a dot position counter of the screen 1,
• the memory means 11 are addressed using the data extracted from the zone table 12,
• a state of display of the point is defined by the data extracted from the storage means 11 at the address obtained by the data of the zone table 12.

The addressing of the first page of the storage means 11 consists, for example, of least significant bits in the addressing of the storage means 11 and the most significant bits of this page are all at a determined value, for example at zero. . The addressing of the storage means 11 with the help of the data extracted from the zone table 12 constitutes the most significant bits in the addressing of the means of storage 11 in addition to the low-order bits previously used.

Advantageously, only a first part of the data item 14 extracted from the zone table 12 is sufficient to address the storage means 11 and the data extracted from the zone table 12 is demultiplexed by means of a second part of the data item 14 extracted from the zone table 12. storage means 11 at the address obtained by the data 14 extracted from the zone table 12. It is thus possible to store several symbol variations in the same data storage means 11. The data of the zone table has for example a eight-bit width. As seen previously, the first of the data 14 of the zone table 12 uses five bits. There remains three bits of the data 14 to demultiplex the data extracted from the storage means 11.

As has been seen previously, the implementation of the invention makes it possible to use only a RAM of very small capacity, the shape of the zones and symbols being stored in a non-volatile memory. Nevertheless, it is easy to modify the zones and the symbols by reprogramming the non-volatile memory without changing the electronic components used to implement the device. This finds, for example, a particular utility when one wants to provide a display device in different countries using different languages.

Claims (6)

1. A device for displaying symbols on a matrix screen (1), comprising:

   a non-volatile memory (11) defining several static zones (2, 3) of the screen (1) and storing, for each zone (2, 3), the status of each point in the relevant zone for several symbols (4, 5) which may be displayed thereon, the stored symbols (4, 5) being specific to each zone (2, 3),

   a main memory containing a zone table (12) defining, for each zone (2, 3), data indicating the retained symbol (4, 5) to be displayed thereon and means (10) for controlling the display of each point of the matrix as a function of the association of the point to a given zone (2, 3) determined in the non-volatile memory (11) and the data indicating the retained symbol (4, 5) for the given zone (2, 3) in the zone table (12).
2. The device according to claim 1, characterised in that addressing non-volatile memory (11) is defined by a counter of the points of the matrix screen (1) and by the information contained in each line of the zone table (2, 3).
3. The device according to any one of the previous claims, characterised in that each zone (2, 3) is identified by a number and the number of the zone associated with the current point forms an address (13) in the main memory and data (14) in the main memory, which is linked to the address (13), defines a variation in the symbol in the relevant zone (2, 3).
4. A process for displaying symbols on a matrix screen, the process using a device according to the previous claims, and for each point on the screen consisting in:

   - determining the zone (2, 3) to which the point is associated by means of the non-volatile memory (11);

   - determining an indication of the symbol (4, 5) to be displayed by means of the zone table (12);

   - generating a display of the point by searching, on the basis of this symbol indication, the non-volatile memory (11) for the status information of the point among the symbols stored in the non-volatile memory (11).
5. The process for displaying according to claim 4, characterised by:

   - addressing a first page of the non-volatile memory (11) by means of a screen (1) point position counter;

   - addressing the zone table (12) by means of the data extracted from the non-volatile memory (11) by means of a screen (1) point position counter;

   - addressing the non-volatile memory (11) by means of the data extracted from the zone table (12);

   - defining a display status of the point using the data extracted from the non-volatile memory (11) to the address obtained by the data in the zone table (12).
6. The process for displaying according to claim 5, characterised in that only a first part of the data (14) extracted from the zone table (12) is sufficient for addressing the non-volatile memory (11), and in that several symbols to be displayed in the relevant zone are multiplexed to the address retained for the non-volatile memory (11) and in that the retained symbol to be displayed in the relevant zone is de-multiplexed by means of a second part of the data (14) extracted from the zone table (12), the data extracted from the non-volatile memory (11) in to the address obtained by the data (14) extracted from the zone table (12).

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