GB2173979A - Character generating system - Google Patents

Abstract

A character generating system for use in a computer comprises a keyboard input/output device 110 adapted to be coupled to a keyboard for transposing a keyed-in character signal into a code. A code buffer 120 receives and stores the code and a cathode-ray tube controller 100 scans the code buffer so as to output the code. A multiplexer 140 is coupled to the code buffer 120 and the cathode-ray tube controller 100 for aggregating the code and a scanning line signal from a scanning address port of the cathode-ray tube controller to output an address code to a memory 150 which stores a plurality of Chinese character patterns and outputs a first pattern signal corresponding to the keyed-in character in accordance with the address code, when the keyed-in character is Chinese. A latch 160 receives and latches the first pattern signal for a predetermined span of time; and a shift register 170, coupled to the latch 160, receives the first pattern signal and converts it into a series of video signals in the predetermined span of time, for display at displayer 190. A second memory 135 may provide English/Arabic characters. <IMAGE>

Description

SPECIFICATION Character Generating System The present invention is related to a character generating system particularly for use in a digital computer system.

Some examples of conventional character generating systems are illustrated in the accompanying drawings, in which: Figure 1 is a flow diagram of one conventional graphic bit map type Chinese character generating system of a computer; Figure 2 is a flow diagram of another conventional graphic bit map type Chinese character generating system; Figure 3 is a flow diagram of another conventional graphic bit map type Chinese character generating system; Nowadays, the Chinese video character signal generating system used in a computer, for the most part, is one of the two types which generally use the graphic bit map method. Referring to Fig. 1, in the graphic bit map method the Chinese characters are first drawn in a dynamic random access memory (dynamic RAM) by way of a dot by dot method, where each dot represents a dot cell of a screen.A video signal generator of the system also has a corresponding memory in which the dotted character desired to be displayed is written from the dynamic RAM by utilizing the software program. Therefore, the central processing unit (CPU) must do a great deal of extra work, which is costly, to process the Chinese character generation and display in addition to processing the operating system (O.S.) and the application software program, so consequently, the displaying speed is low. Moreover, the storage of the Chinese characters occupies a large amount of memory, adding greatly to the cost.

The graphic bit map method includes two types as follows: (awl). Referring to Fig. 2, this system utilizes a Chinese character generator which stores a lot of basic patterns of Chinese characters, and a character generating software to compose a Chinses character with several basic patterns. The main drawback of the system is that the generating speed is merely 30 to 60 characters per second, and that the composed Chinese character has to be stored in a corresponding display memory. Thus, the CPU must do extra work to process the character generation, and the user must pay forth time it takes to display the characters.

(a2). Referring to Fig. 3, this system utilizes a read only memory (ROM) in which the Chinese characters have been written for the CPU to retrieve a character and store it in a display memory. Such a system wastes a large amount of memory to store the Chinese characters, wastes many hours retrieving the characters, and the number of the characters capable of being stored for display is insufficient.

Furthermore, in the conventional computer system the character spacing, which has to be added specially in the upper and lower portions of the Chinese character for the characters on different lines to be displayed a little distance apart from each other, is processed by the CPU. It inserts the spacing code OOH ("H" generally labels a hexadecimal digit in the computer field) into the proper place of the display memory corresponding to the character spacing of the keyed-in character on the screen, resulting in much wasted memory space for storing the spacing code, while the CPU does extra work to process the character spacing. In addition, the conventional computer system achieves several special displaying effects, such as inverse, flash, underline, and highlight, by use of a plurality of logic gates, counters, and oscillators, adding greatly to the cost.

A character generating system for use in a digital computer system according to one preferred embodiment of the present invention intends to improve on the above-described drawbacks.

In accordance with the present invention, a character generating system in a computer comprises a keyboard input'output device adapted to be coupled to a keyboard for transposing a keyed-in character signal into a code; a code buffer coupled to the keyboard input"output device for receiving the code and storing it therein; a cathode-ray tube controller coupled to the code buffer for scanning the code buffer so as to output the code at the output port of the code buffer; a multiplexer coupled to the code buffer and the cathode-ray tube controller for aggregating the code and a scanning line signal from a scanning address port of the cathode tube controller to output an address code; a memory which stores a plurality of Chinese character patterns coupled to the multiplexer for receiving the address code to output a first pattern signal corresponding to the keyed-in character in accordance with the address code, when the keyed-in character is Chinese; a latch coupled to the memory for receiving and latching the first pattern signal for a predetermined span of time; and a shift register, which is adapted to be coupled to a displayer, coupled to the latch for receiving the first pattern signal and converting it into a series of video signals in the predetermined span of time, and then sending the series of video signals to the displayer.

The present invention provides a character generating system for use in a digital computer system which utilises the hardware circuit to swiftly and properly deal with the character generating process.

Preferably, the latch includes means for adding character spacing to said keyed-in character. This means for automatically adding the character spacing to the keyed-in character saves CPU processing time.

The present invention may also include a special display effects processor to easily achieve several displaying effects without designing a complicated hardware circuit.

In some examples, the character generating system may generate English (or Arabic) and Chinese characters and include means for recognising the attributes of the character keyed-in by the user in order to properly, respectively deal with the Chinese character generation and the English character generation.

The present invention will be more fully understood from the following detailed description, taken in connection with the accompanying drawings which are an integral part of this application and in which: Figure 4 is a flow diagram .;f a charactcr generating system for use in a digital computer system in accordance with one preferred embodiment of the present invention; Figures 5(a) to 5(i) are schematic views of a recognising means of the present invention, showing the processing steps of recognising the attributes of the keyed-in characters; Figure 6(a) is an electrical schematic diagram of a deleting means coupled with a first programmable array logic, forming a portion of a character spacing adding means, in accordance with the present invention;; Figure 6(b) is an electrical schematic diagram of a spacing code generator of the character spacing adding means in accordance with the present invention; and Figure 7 is an electrical schematic diagram of a special displaying effects processor in accordance with the present invention.

Referring now to Fig. 4, the character generating system in accordance with the present invention utilizes a keyboard input'output device 110 coupled to a keyboard (not shown) for transposing a Chinese or English character signal keyed in by the user to a code which represents the keyed-in character, a code buffer 120 coupled to the keyboard input'output device 110 for receiving the code and storing it therein, and a cathode-ray tube controller 100 coupled to the code buffer 120 for automatically scanning the code buffer 120 so as to output the code at the output port of the code buffer 120.The system comprises means 130 for recognizing the attribute of the keyed-in character which has a first and a second output ports 131 & 132, and which is coupled to the code buffer 120 for receiving its outputted code in order to output the code at the first output port 131 if the keyed-in character is Chinese, or at the second output port 132 if the keyed-in character is English.

If the keyed-in character is English, the code outputted at the second port 132 is sent to an English character generator 135, which is generally used in the English digital computer system, for generating a second pattern signal of the keyed-in character at its output port by way of the known method. If the keyed-in character is Chinese, the code outputted at the first output port 131 is sent to a multiplexer 140 which is also coupled to the cathode-ray tu be controller 100 for receiving a scanning line signal from a scanning line address port 105. The multiplexer 140 aggregates the code for the Chinese character and the scanning line signal from the cathode-ray tube controller 100 to output an address code on its output port.

The address code is then sent to a memory 150 which stores a plurality of Chinese character patterns for retrieving a first pattern signal of the keyed-in Chinese character stored in the memory 150. The memory 150 may be a mask read only memory according to one preferred embodiment of the present invention. A latch 160 is coupled to both outputs of the mask read only memory 150 and the English character generator 135 for receiving the first or second character pattern signal, and then latching the pattern signal over a predetermined span of time. A shift register 170 is coupled to the latch 160 for converting the pattern signal into a series of video signals during said predetermined span of time in order to display on the screen of a displayer 190 coupled to the shift register 170.The latch 160 may be constructed with means 165 for automatically adding the character spacing to the keyed-in character for implementing the character spacing function by the hardware circuit, which will be further described later. A special displaying effects processor 180 may be coupled between the shift register 170 and the displayer 190, as shown in Fig. 4, for further providing the function of easily generating the special displaying effects for the keyed-in character, and this also will be further described later.

It should be noted that the recognizing means 130 and the English character generator 135 can be excluded from the above-described embodiment of the present invention if a Chinese character generating system is needed only. Apparently, by way of the hardware circuit of such a Chinese character generating system, the function of directly implementing the Chirese character generating process without the CPU doing extra work still can be achieved.

In this embodiment of the present invention, the keyboard input'output device 110 transposes a keyed-in Chinese character into two units of code signal (wherein one unit is 8 bits), and an English character into a single unit of code signal. Therefore, if an English character is keyed in by the user, the code buffer 120 will send out a single code, and if a Chinese character is keyed in, the code buffer 120 will discontinuously send out two codes. Moreover, the recognizing means 130 is capable of supplementing a "00" code to the code for concurrently outputting the two codes at the second output port 132, if the keyed-in character is English. If the keyed-in character is Chinese, the recognizing means 130 is also capable of waiting until both of the codes for a Chinese character have reached the recognizing means 130 and are stored therein before it actuates the two codes concurrently at the first output port 131.

In the recognizing means 130 and the video signal generating process, the data code and the attribute code are generated synchronously. The data code representing a specific character or figure is converted into a video signal by the hardware circuit, and then is shown on the screen of the displayer 190. The attribute code represents the attributes, for example English or Chinese, of the character, or some special effects such as inverse or flash.

Referring to Fig. 5(a), the recognizing means 130 utilizes a set of registers 10, 20, 30,40, 50, and 60 to transiently store the data codes, and a state recognizer which includes a set of state registers 1, 2 & 3 and a state decoder 136 for transiently storing the attribute code and-for recognizing the attributes of the keyed-in character for actuating the data code stored in the set of registers and outputting the data code at the first or the second output port 131 or 132 properly. The state recognizer is coupled to the code buffer 120 via two lines, or two recognizing bits ATO and AT1 to achieve the function of recognition (referriny to Table I). In this embodiment, the state register 2 will actuate the register 30 if it is set to "1", or will actuate the register 40 if it is set to "0".The state decoder 136 has two output ports CS (Chinese Start) connected to the register 60 and ES (English Start) connected to the register 50, and is connected to all the outputs of the state registers 1, 2 & 3 for actually starting the Chinese character generation or the English character generation (referring to Table II). The detail of the functions of the recognizing means 130 will be fully described in connection with one example hereinafter.

TABLE I

&verbar; AT0=0 AT0=1 AT1=0 ENGLISH The first code of CHINESE AT1 =1 ENGLISH The second code of CHINESE TABLE II

State register State register State register (1) (2) (3) CS ES 0 0 O X 0 0 1 x 0 1 0 X 1 0 0 x 1 0 1 x The example is to key in five characters "A";; "cup"; "t"; "B"; and "C". Referring to Fig. 5(b) and Table I & II, the code 81 of the "A" character first reaches the fronts of the registers 10 and 30. Since the "A" is an English character, the recognizing bits ATO=0, AT1 =0, and the state register 1 is set to 0.

Referring to Fig. 5(c), when the first code 82 of the next Chinese character "E1" (which has two codes) reaches the fronts of the registers 10 and 30, the previous code 81 is pushed to the front of the register 20, and is concurrently pushed into the register 30. Since the code 82 is the first code of the Chinese "E1", the recognizing bits AT0= 1, AT1 =0, the state register 1 is set to 1, and the state register 2 is set toO. The state register 2 actuates the register 40 to supplement a "00" code 83 into the register 40.

Referring to Fig. 5(d), when the second code 84 of the Chinese "" reaches the fronts of the register 10 and 30, the code 81 of the "A" character and the "00" code 83 are concurrently stored in the register 50.

Since "A" is an English character, from Table II, the state decoder 136 actuates the register 60 to start the English character generation, and thus two codes 81 and 83 are converted into a video signal to display the "A" character on the screen of the displayer 190 via the general English character generator 135, the latch 160 with the character spacing generating means 165, the shift register 170, and the special displaying effects processor 180. At this time, the code 82 is also pushed to the front of the register 20, and concurrently into the register 30. Since the code 84 is the second code of the "cup" character, the recognizing bits ATO 1, AT1 = 1, the state register 1=0, the state register 2=1, and the state register 3=0.The state register 2 will actuate the register 30 to send out the data code, and the state decoder 136 will start the Chinese character generation.

Referring to Fig. 5(e), when the first code 85 of the next Chinese character "t" (which has two codes) reaches the fronts of the registers 10 and 30, both the first and second codes 82 and 84 of the "c" character are actuated by the state register 2 to be stored in the register 60. Since the "cl" is a Chinese character, the state decoder 136 actuates the register 60 to start the Chinese character generation, and thus the codes 82 and 84 are sent to the second output part 132 of the recognizing means 130, and then, the "" character is shown on the screen of the displayer 16 via the memory 150, the latch 160 with the character spacing generating means 165, the shift register 170, and the special displaying effects processor 180.Since the code 85 is the first code of the character "t", the recognizing bits ATO=1, AT1 =0, the state register 1 =1, the state register 2=0, and the state register 3=1. From table 11, the state decoder 136 will start the English character generation, however, since the code unit of the Chinese character is double that of the English character, resulting in the fact that the displaying time of the Chinese character is also double, at this time the lower half of the character "" is still being displayed. Therefore, the state decoder 136 is designed to make no action at this time.

Referring to Fig. 5(f), when the second code 86 of the character "t" reaches the fronts of the registers 10 and 30, the first code 85 of the "t" is pushed to the front of the register 20, and concurrently into the register 30. Since the code 86 is the second code of the "1"', the recognizing bits ATO 1, AT1 = 1 ,the state register 1=0, the state register 2=1, and the state register 3=0. The state register 2 will actuate the register 30 to send out the data code. The state decoder 136 will start the Chinese character generation.

Referring to Fig. 5(g), when the code 87 of the "B" character reaches the fronts of the registers 10 and 30, the first and second codes 85 and 86 are stored in the register 60, and the Chinese character generation is started by the method mentioned above. Since the "B" is an English character, the recognizing bits ATO=O, AT1 =0, the state register 1=0, and the state register 2=0.

Referring to Fig. 5(h), when the code 88 of the "C" character reaches the fronts of the registers 10 and 30, the code 87 of the "B" is pushed to the front of the register 20, and concurrently into the register 30.

Since the "C" is an English character, the recognizing bits ATO=O, AT1 =0, the state register 1=0, the state register 2=0, and the state register 3=1. The state register 2 will actuate the register 40 and supplement a "00" code 89 into the register 40. The state decoder 136 will start the English character generation.

Referring to Fig. 5(i), no matter what attributes the next code 90 has, both the code 87 of the "B" and the code "00" 89 are stored in the register 50 for showing the "B" on the screen by the same method described above.

Referring now to Figs. 6(a) and 6(b), there are shown the character spacing adding means 165 which includes a deleting means 166 coupled to the scanning address port 105, including lines RAO to RA4, a first programmable logic array (PAL) 167 coupled to the deleting means 166, and a spacing code generator 168 coupled to the first PAL 167. In this preferred embodiment of the present invention, since one line for displaying the characters on the screen utilizes twenty scanning lines, and the pattern of the character is merely represented by a 1 6x 16 dot matrix mode, the two uppermost and the two lowest scanning lines of each displaying line should leave blanks, called "character spacing".In conventional computers they directly insert zero into the proper positions in the display memory corresponding to the displaying position on the screen. In the present invention the character spacing adding means 165 is utilized to automatically send out a spacing code "00" for carrying out the character spacing when scanning the two uppermost and the two lowest scanning lines. The deleting means 166 is coupled to the scanning address port RAO to RA4, and deletes the scanning address by two, and then outputs on the lines SLO to SL4. That is achieved by two adders, using for example the IC chip of 74LS83, and connected as shown in Fig. 6(a). Since one displaying line needs twenty scanning lines, the scanning address is changed from OOH to 13H represented by RA4-RAO in binary mode.After the deleting process, the number represented by SL4-SLO in binary mode is changed from -02H to 11 H, therefore, when presenting the two smallest numbers -02H & -01 H and the two largest numbers 10H & 11 H the SL4 line is caused to output a logical high state "1 ". The first PAL 167 is programmed to detect the output of the SL4 line, and to actuate the spacing code generator 168 via the HWSPACE line to send out a spacing code "OOH" for carrying out the character spacing process when the output of the SL4 line isin a logical high state. The spacing code generator 168 is constructed by the 74LS125 and 74LS244 IC's as shown in Fig. 6(b).

Referring to Fig. 7, there is shown the electrical schematic diagram of the special displaying effects processor 180 which includes two second programmable array logics 185 connected as shown and programmed to carry out the special displaying effects, including inverse, flash, underline and highlightfor the keyed-in character, as well as vertical lines and horizontal lines for easily establishing a reporting form.

Claims (14)

1. A character generating system comprising: a keyboard input'output device adapted to be coupled to a keyboard for transposing a keyed-in character signal into a code; a code buffer coupled to said keyboard input'output device for receiving said code and storing it therein; a cathode-ray tube controller coupled to said code buffer for scanning said code buffer so as to output said code at the output port of said code buffer; a multiplexer coupled to said code buffer and said cathode-ray tube controller for aggregating said code and a scanning line signal from a scanning address port of said cathode-ray tube controller to output an address code;; a memory which stores a plurality of Chinese character patterns coupled to said multiplexer for receiving said address code to output a first pattern signal corresponding to said keyed-in character in accordance with said address code, when said keyed-in character is Chinese; a latch coupled to said memory for receiving and latching said first pattern signal for a predetermined span of time; and a shift register, which is adapted to be coupled to a displayer, coupled to said latch for receiving said first pattern signal and converting it into a series of video signals in said predetermined span of time, and then sending said series of video signals to said displayer.

2. A system as claimed in claim 1, wherein the pattern of said keyed-in character is represented by a 16x16 dot matrix mode.

3. A system as claimed in claim 1 or claim 2, wherein said latch includes means tor adding character spacing to said keyed-in character.

4. A system as claimed in claim 3, when dependent on claim 2, wherein said character spacing adding means includes a decrementing means coupled to said scanning address port of.said cathode-ray tube controller for decrementing said scanning address by two, a first programmable array logic coupled to said decrementing means for detecting the output of said decrementing means, and a spacing code generator coupled to said first programmable array logic for being actuated to send out a spacing code when a preselected output of said decrementing means is in a Igoical high state, whereby adjacent lines of displayed characters are spaced from one another.

5. A system as claimed in any of claims 1 to 4, further comprising a special displaying effects processor through which said shift register is coupled to said displayer, and which is capable of generating at least one of a plurality of special displaying effects, including inverse, flash, underline and highlight for said keyed-in character, and vertical and horizontal lines.

6. A system as claimed in claim 5, wherein said special displaying effects processor includes two programmable array logics coupled to each other, and programmed to implement the special displaying effects.

7. A system as claimed in any of claims 1 to 6, for generating English and Chinese characters, further comprising: means for recognizing the attributes of said keyed-in character, having a first and a second output ports, wherein said multiplexer is coupled to said code buffer through said second output port of said recognizing means, and said recognizing means receiving said code outputted from said code buffer in order to output said code at said first output port when said keyed-in character is English, and at said second output port when said keyed-in character is Chinese; and an English character generator respectively coupled to said first output port of said recognizing means and said latch for receiving said code outputted from said first output port to generate a second pattern signal of said keyed-in character, and then sending said second pattern signal to said latch.

8. A system as claimed in claim 7, wherein said recognizing means includes a set of registers coupled to said code buffer, and a state recognizer coupled to said code buffer and said set of registers respectively, said set of registers receiving said code from said code buffer and transiently storing said code therein, and said state recognizer recognizing the attributes of said keyed-in character for actuating said code stored in said set of registers outputting at said first output port when said keyed-in character is English, and at said second output port when said keyed-in character is Chinese.

9. A system as claimed in claim 8, wherein said keyboard input/output device transposes a keyed-in Chinese character into two units of code, and a keyed-in English character into a single unit of code.

10. A system as claimed in claim 9, wherein said state recognizer is capable of suppiementing a "00" code to said code when said keyed-in character is English.

11. A system as claimed in claim 10, wherein when said keyed-in character is Chinese, said state recognizer is capable of waiting until both units of said code have reached and are stored in said set of registers, before it actuates said code outputting at said second output port.

12. A system as claimed in claim 11, wherein said memory is a mask read only memory.

13. A character generating system substantially as hereinbefore described with reference to Figures 4 to 7 of the accompanying drawings.

14. A digital computer system comprising a character generating system according to any of the preceding claims.