JPS6335033B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display control method in a dot matrix type display device that displays alphanumeric characters, and in particular, by displaying characters and symbols overlappingly on the same digit of the display device.
To provide a display control method that further expands versatility by diversifying patterns stored in a small-capacity character generator.

When constructing a dot matrix type display device, a character generator or other pattern generator that stores various display patterns is required. An appropriate generator is selected depending on the purpose. Note that there are two types of character generators: column scan type and row scan type.

Needless to say, it is desirable from a cost standpoint that these character generators have a capacity as small as possible relative to the type of pattern that can be displayed.

By the way, in the case of a small-capacity general-purpose character generator that is usually composed of ASC codes, patterns such as "a¨" and "u¨" in German and "o^" and "e'" in French etc. Not remembered. Therefore,
If you need to display "a¨" or "o^" etc.,
Separately create patterns such as "¨" and "^" that are not found in the ASC code, and use two display digits to display characters and symbols separately, such as "a" and "¨", or by country of destination. This was dealt with by replacing it with a character generator that had a pattern for the compound characters "a¨", "u¨", etc.

However, with the method of separating and displaying two digits,
Not only is it difficult to see, but the display surface cannot be used effectively. Furthermore, in the method of storing each compound character, the capacity of the character generator increases, the versatility is lost, and the cost increases.

In addition, as compound characters, “” and “3” are also available.
Characters with symbols indicating complements, such as
There are also accent marks such as "'" and "｀", and it is not very practical to memorize all of them, considering the increased capacity of character generators and the frequency of their use. Therefore, in order to display such special symbols such as " ^- ", "´", "｀", etc., a method of using an independent buffer memory and a pattern generator is also being used. However, this method requires a complicated display control circuit.
At the same time, it also causes an increase in costs.

Therefore, the display control method of the present invention solves these inconveniences in the conventional method of displaying compound characters, and uses common patterns such as "¨" and " ^- " to Intended to be displayed in duplicate.

FIGS. 1 and 2 show display examples of characters that can be displayed in an overlapping manner using the display control method of the present invention.
Figure 1 shows the German city name "Mu¨nchem",
"u¨" is a superimposed character. Also, Figure 2 shows
"""""a´""$""Θ""÷""""￥"
It shows each superimposed character.

In the display example of FIG. 2, for example, if " ^- " and an alphanumeric character are superimposed, it becomes a character representing a complement. Also, if "-" and "0" are superimposed, "Θ" will be displayed, and if "=" and "Y" are superimposed, "\" will be displayed.

In this way, by overlapping two or more types of character symbols, "Θ" or "¥" can be displayed, so the pattern "Θ", "¥", etc. can be stored in the character generator. There's no need.
Since it becomes possible to store other necessary patterns in the empty memory, more types of character symbol patterns can be stored in the character generator of the same capacity.
As a result, the same character generator can be used for displaying foreign languages such as German and French, further increasing versatility.
In addition, it is possible to effectively utilize the display surface, and it is also possible to provide an easy-to-read display.

In addition, in the case of the display examples in Figures 1 and 2, 1
The dot pattern of the digit is composed of 6 dots horizontally by 9 dots vertically, and five character dot columns and one space column are arranged in the row direction, that is, the horizontal direction. Similar to the conventional dot matrix type display device, any number of such dots can be used.

FIG. 3 shows the format of display data used in the display control method of the present invention. In this Figure 3, the display data shown on the left side is stored.
This shows a state in which data for displaying "Mu¨nchem" shown in FIG. 1 above has been input to a buffer memory such as RAM. In other words, data "M" is stored at address N, data "u" is stored at the next address (N+1), data "¨" is stored at address (N+2), and so on. do.

In the format shown in Figure 3, the data code LSB is 7, as shown enlarged on the right side.
In a bit structure, a code indicating the address of the character generator, such as an ASC code, is stored, and the 1-bit MSB is used as a superposition code for instructing superposition display. In this superimposition code MBS, "1" is given to the data "u" to be superimposed on the next character symbol, and "0" is given to the data "¨" for normal display.

This superimposition code MSB can be given as "1" to display data to be superimposed on the next display data when inputting display data by key or when processing data in the CPU. and,
The overlapping code MSB "1" can be added to any character symbol, and there is no need to change the display control circuit for overlapping display of any character notation.

FIG. 4 is a block diagram showing an example of the circuit configuration of a display interface section used when implementing the display control method of the present invention in a column scan type display device. In the drawing, 1 is an input/output port, 2 is a buffer memory such as RAM that stores display data, 3 is an address counter for the display data buffer 2, and 4 is a buffer memory that holds the display data output from the data buffer 2 for the time required to display one digit. , 5 is a column scan type character generator, 6 is a column counter for specifying the character generator 5 and the column of the display device, 7 is a digit counter for specifying a digit (display digit), and 8 is a column counter for specifying the column of the display device. Decoder, 9 is an AND gate circuit group, 10 is a pattern memory for temporary storage, 11 is an OR gate circuit group, 12 is a driver, 13 is a decoder/driver, G1 to G3 are inverters, G4 and G5 are AND gate circuits, S1 ~S9 is a segment selection signal, C1~C
6 represents a column selection signal, and D1 to Dn represent digit selection signals.

In the circuit shown in FIG. 4, a temporary storage pattern memory 10 is provided to temporarily store the one-digit dot pattern output from the character generator 5. The display data is delayed by one digit by this temporary storage pattern memory 10, and is sent to the segment electrodes S1 to S9 via the OR gate circuit group 11 together with the dot pattern of the next display data. There is.

That is, when the superposition code MSB added to the display data LSB is "0" indicating normal display, the output of inverter G1 is "1".
Then, the AND gate circuit group 9 is selected, and the dot pattern for each column of the character generator 5 is applied to the segment electrodes S1 to S9 via the OR gate circuit group 11, thereby performing a normal display. In this case, when one digit has been displayed,
The address counter 3 that accesses the data buffer memory 2 and the digit counter 7 that selects the display digit are operated so that they are simultaneously incremented and the dot pattern of the next display data is displayed in the next display digit. Ru.

On the other hand, when the superposition code MSB is "1", which instructs superposition display, the output of inverter G2 becomes "1", the gate on the temporary storage pattern memory 10 side is opened, and the character All the one-digit dot patterns sent out from the generator 5 are stored in this temporary pattern memory 10.
can be stored in When the storage of this pattern is completed, the address counter 3 is incremented and the next display data is accessed. However, the input to the digit counter 7 is blocked, and the display device is not shifted, and the same digit continues to be selected.

In this way, the temporary storage pattern memory 1
The dot pattern for one digit stored in 0 is output to the OR gate circuit group 11 column by column in synchronization with the dot pattern of the next normal display data being sent out from the character generator 5. . That is, the dot pattern of the next normal display data sent out from the character generator 5 through the AND gate circuit group 9 and the superimposed display of the previous digit sent out from the temporary storage pattern memory 10. The instructed display data is added column by column by the OR gate circuit group 11,
The light is sent to segment electrodes S1 to S9, and a lighting display is performed for each column.

FIG. 5 is a partially enlarged view showing the structure of a column scan type dot matrix display device. In the drawing, D1, D2, . . . are digit electrodes corresponding to respective display digits, C1 to C6.
are column electrodes corresponding to each column of display digits, S1
~S9 indicates segment electrodes corresponding to each dot in the vertical direction.

In this display example, the 1-digit pattern is 6 horizontal x 9 vertical.
(dots), the column electrodes are arranged in six columns C1 to C6. Further, the segment electrodes are arranged in nine rows S1 to S9.

In the display device of FIG. 5, both the digit electrode and the column electrode are energized, and only the dots to which the segment selection signal is applied as "1" are lit.

The following FIG. 6 is a time chart for explaining the operation of the circuit shown in FIG. 4. In the drawing,
DISP is a timing signal that indicates the display cycle;
Other waveform symbols indicate signals at corresponding symbol positions in FIG.

Next, using the circuit shown in FIG. 4, the operation when displaying the German word "Mu¨nchem" as in the display example shown in FIG. 1 will be explained.

Display data is transferred from an external CPU to a data buffer memory 2 via an input/output port 1 and stored therein. The state is as described in connection with FIG. 3 above.

The display data stored in the data buffer memory 2 is sequentially read out by the address counter 3 driven by the clock pulse Φ and transferred to the buffer memory 4 together with the superimposed code MSB in the display cycle DISP. The display data LSB held in the buffer memory 4 becomes an address code indicating a pattern block of the character generator 5.

When performing the display shown in FIG. 1, the character generator 5 stores one pattern in a matrix configuration of 5 horizontally by 9 vertically (bits), and stores a character column of 5 bits in the row direction, that is, in the horizontal direction. A total of six columns are sent out, making up a 1-bit space column. The column counter 6 controls this column sending, and in this case, a hexadecimal counter is used. The output of this column counter 6 is also used as column selection signals C1 to C6 of the display device through a decoder 8 and a driver 12.

Further, the overflow signal of the column counter 6 becomes the output of the AND gate circuit G4, and the address counter 3 of the data buffer 2 is incremented. Therefore, the data buffer 2 outputs the following display data.

On the other hand, the digit counter 7 has a superimposition code MSB of "0" indicating normal display.
Different operations are performed depending on whether the flag is "1" or "1", which instructs superimposed display. That is, when the superposition code MSB is "0", the output of the inverter G1 is "1", so the AND gate circuit G5 is
gate is opened, and the output of the AND gate circuit G4 in response to the overflow signal of the column counter 6 increments the digit counter 7, and the display is shifted. However, when it is "1" indicating overlapping display, the AND gate circuit G5
gate is closed, so selection of the same display digit continues.

In the initial state, address counter 3, column counter 6, and digit counter 7
are all set to "0". Therefore, due to the output AC=0 of address counter 3,
In the data buffer memory 2, the code of the first data "M" is output, and this code is held in the buffer memory 4. This buffer memory 4 is a memory for holding the address of the character generator 5 while displaying one digit, and also holds the superposition code MSB, and in the initial state, the pattern "M" is Specifying the address.

Further, the digit counter 7 selects the first digit D1 of the display device by its output "0".

In the case of the pattern "M" in which the first column C1 of the character generator 5 is specified by the output "0" of the column counter 6, the superposition code MSB is "0" which also indicates normal display. Therefore, the output of inverter G1 becomes "1", and the gate of AND gate circuit group 9 is opened.

Therefore, total 9 for one vertical column of pattern "M"
The dot patterns are sent from AND gate circuit group 9 to segment electrodes S1 to S9 via OR gate circuit group 11, respectively. At the same time, the output “0” of this column counter 6 is sent to the decoder 8,
The first column C1 of the column electrodes is selected via the driver 12.

In this way, the first column of the pattern "M" is illuminated and displayed in the first column C1 of the first digit D1 of the display device.

Next, when the clock pulse Φ is generated, the column counter 6 is counted up once and becomes the output "1", and the character generator 5 and the second column C2 of the column electrode are selected and the pattern "M" is selected. A lighting display is performed in the second column.

A similar operation is repeated every time a clock pulse Φ is generated, and the output of the column counter 6 becomes "4" by the fourth clock pulse, and the fifth column C5 is lit. In this way,
The lighting display of all five columns C1 to C5 of the first digit D1 ends.

At the time when the next clock pulse Φ is generated,
The column counter 6 is counted up one more time and selects the 6th column C6, but since there is no corresponding address in the character generator 5, it is invalidated, no pattern output is generated, and space is secured. . Note that the column counter 6 at this time
The output (A ₁ -A ₃ ) becomes "011", and the output "1" is generated from the AND gate circuit G4, causing the address counter 3 to count up, and the output of the address counter 3 becomes AC=1. Therefore, the data buffer 2 outputs the second digit "u" code and stores it in the buffer memory 4.

In the case of the previous pattern "M", the superposition code
Since the MSB is given as "0" which indicates normal display, the output "1" of the AND gate circuit G4 causes the output "1" to be generated from the AND gate circuit G5, and the digit counter 7 also starts counting up. The digit selection signal becomes the second digit D2. Therefore, the display device can display the second digit by lighting.

However, the superposition code MSB of the second digit "u"
Since is "1", the AND gate circuit group 9 is inhibited by the output of the inverter G1,
Segment selection signals S1-S9 are not generated.
As a result, the lighting display of the second digit is not performed.

All pattern outputs sent from the character generator 5 every time the clock pulse Φ is generated are stored in the pattern memory 10 for temporary storage.

In this embodiment, the temporary storage pattern memory 10 is composed of 6 bits horizontally and 9 bits vertically.
Like the column counter 6, it is driven by a clock pulse Φ and is a one-way discharge memory.

When all the "u" patterns are stored in the pattern memory 10, an overflow output is generated from the column counter 6 by the next clock pulse Φ, and an output "1" is generated from the AND gate circuit G4.
is generated. Therefore, the output of address counter 3 becomes AC=2, and data buffer 2 to 3
The code in digit “¨” is sent.

Since the superposition code MSB of "¨" is "0", the pattern output of the character generator 5 is sent to the OR gate circuit group 11 through the AND gate circuit group 9. At the same time, the pattern output of the previous "u" is sent from the temporary storage pattern memory 10 to the OR gate circuit group 11, and the dot pattern output added by this OR gate circuit group 11 is added column by column. Segment electrode S1
~S9, each column C1~C of the second digit D2
5 will be lit and displayed.

In this way, the superimposed character "u¨" is displayed, and at the end of this cycle, since the superposed code MSB is "0", the digit counter 7 is incremented along with the address counter 3, and the next Move to the displayed digit.

In this way, regarding the input display data,
If the superimposition code MSB of the character symbol to be displayed superimposed on the next character symbol is set to "1", the circuit shown in FIG. 4 allows the character symbol to be displayed redundantly on the same display digit. This is exactly the same in the display of superimposed characters "", "", etc. shown in FIG.

In the circuit shown in FIG. 4, only one temporary memory pattern memory 10 is used, but if a plurality of such pattern memories are provided in parallel, three or more superimposed characters can be stored in one It is also possible to display it in digits.

Further, in this embodiment, a column scan method has been described. However, in the case of the low scan method, the only difference is that one line of dot patterns is converted from parallel to serial and output for each digit of the display, and in the case of the low scan method,
In order to superimpose and display the display data specified by the superimposition code MSB, the dot pattern for each digit and one line is stored in the temporary storage pattern memory and added to the dot pattern for the next one digit and one line. If the data is sent to the X dot buffer memory, it can be implemented in the same way as the column scan method.

As explained in detail above, in the display control method of the present invention, in a character display device that displays alphanumeric characters configured as dots on a display screen, the LSB of display data transferred to this display device is Bit information MSB indicating whether or not the character signal is a superimposed character is added, and based on the detection result of this instruction bit information MSB, if the character signal is a superimposed display character, the shift of the display digits is stopped, The display pattern is stored in a temporary storage pattern memory that can store display patterns for one digit, and added together with the display pattern of the next normal display by a logic OR gate circuit, and then supplied to each segment electrode of the display device. ing.

Therefore, display patterns stored in pattern generators such as character generators can be combined to display overlapping characters, and patterns stored in pattern generators such as character generators with the same capacity can be stored in a variety of ways. This makes it possible to use the same pattern generator for special characters from other countries such as German and French.
The characters and symbols to be compounded are the superimposition instruction bit MSB added to the input display data.
This is possible for all character symbols stored in the pattern generator by simply changing . On top of that,
Since the display control circuit used for this purpose is also relatively simple, many excellent effects can be achieved, such as the overall cost of the display device being reduced.

[Brief explanation of the drawing]

1 and 2 are display examples of characters that can be displayed in combination by the display control method of the present invention, FIG. 3 is a format of display data used in the display control method of the present invention, and FIG. 4 is a display example of the present invention. FIG. 5 is a block diagram showing an example of the circuit configuration of a display interface section used when implementing the display control method of FIG. The partially enlarged view of FIG. 6 is a time chart for explaining the operation of the circuit of FIG. 4. In the drawing, 1 is an input/output port, 2 is a buffer memory such as RAM that stores display data, 3 is an address counter for the display data buffer 2, 4 is a buffer memory that holds display data for the time required to display one digit, and 5 is a column scan type. 6 is a column counter, 7 is a digit counter, 8 is a decoder, 9 is an AND gate circuit group, 10 is a pattern memory for temporary storage, 1
1 is an OR gate circuit group, 12 is a driver, and 13 is a decoder/driver.

Claims (1)

[Claims] 1. In a character display device that displays alphanumeric characters composed of dots on a display screen, an instruction to add instruction information to display data indicating that the character is a superimposed character, and to detect the instruction information when displaying the data. Information detection means and superposition control means for controlling superposition based on the detection result of the instruction information detection means are provided, and normally a one-digit display pattern based on the display data is displayed, and the instruction information is displayed in superposition. , the superimposition control means superimposes a display pattern for one digit based on the display data and a display pattern for one digit based on the next display data and displays it as a display pattern for one digit. A display control method characterized by: