JPS61282923A - External character register memory system for printer - Google Patents

Abstract

PURPOSE:To stop an unused external character register memory area from idling by setting a font data register area which an address conversion table designates in accordance with count information of a counter. CONSTITUTION:When an external character is registered, a table address of the address conversion table is generated by the value of a prescribed bit of the external character code, and the start address of font data in the external character register memory area is designated in accordane with this table address. Since the counter counts the number of unregistered external characters or the number of registered external characters at this time, the start address of font data is designated in accordance with the counted value. Thus, font data are stored in the external character register memory area successively from the end to the start of from the start to the end independently of the external character code at the external character registering time.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a control method for a printer's external character registration memory (prior art). (hereinafter referred to as ROM) and random access memory (hereinafter referred to as RA) for writing and reading various data.
M) is always provided, but traditionally this RA
Many use a part of the M memory area as a non-standard character registration area.

Registering external characters means storing character shapes, symbols, or figures (hereinafter referred to as fonts) that the user wants to use independently in the printing device online before outputting the print code to the printer. One font to be registered is multiple bytes in RAM (for example, 24 dots x 24
In the case of a dot kanji matrix, 72 bytes) are stored as font data in one memory block, and if you decide that one non-standard character code corresponds to this one memory block, you can receive that non-standard character code from now on. Just by doing this, you can read the font data and print.

Conventionally, the order of the fonts in the private character registration area corresponds to the order of the private character codes, and the method of finding the start address of font data from the private character code is the seventh method.
There are two methods: the semi-direct addressing method shown in the figure and the indirect addressing method shown in FIG.

First, to explain the semi-direct addressing method, in this method, the value β of the lower S bits of the received private character code is multiplied by the number of bytes per font α, and the start address N of the private character registration area is added to this. (N+α·β) is calculated and set as the start address of the corresponding font data. Here, S is the minimum integer that satisfies K≦2s, where K is the allowable number of registered characters, and β is the value indicated by the lower S bit of the custom character code in binary y, which is θ ~ (K-1). .

Next is the indirect addressing method, which is the same until the lower S bits of the private character code are used, but in this case, the ROM area has an address conversion table, and the lower S bits of the private character code are stored in this table. used to create an address. The number of tables is the same as the permissible number of registered characters, but if the RAM address requires 2 bytes, the table will consist of 2 bytes, and if the first ROM address of the address conversion table is M, then (M+2β)
becomes the table address. The data in the table specified in this way is the start address of the font data corresponding to the private character code. In FIG. 8, H and L each indicate the upper byte and lower byte of the 2-byte RAM address.

Here, in the case of the semi-direct addressing method, an address conversion table is not required, but since it requires calculation to obtain the start address of the font not only when registering but also when reading, reading is required during high-speed printing. In this case, if the processing capacity of the microprocessor is small, multiplication operations etc. take too much time, making it unsuitable. Conversely, in the case of indirect addressing,
Although it is necessary to have an extra address conversion table, it is suitable for high-speed processing because it does not require troublesome multiplication operations (if it is only 2 times, it can be easily done by bit shifting).

(Problem to be Solved by the Invention) However, in the two conventional addressing methods, the font data corresponding to the non-standard character code is both at a fixed position in the non-standard character registration RAM area, and the user must select the non-standard character code at the beginning. Alternatively, unless the data is registered in order from the rear end, the RAM usage result will be as shown by the shaded area in FIG. Therefore, the number that can be registered is reduced, and no matter how large the free area is, it is extremely difficult to use it for other functions, resulting in a disadvantage that the player is wasted.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawback of the prior art in that the unused character registration memory area is wasted, and to enable it to be easily used as a memory expansion area for other functions.

(Means for Solving the Problems) In order to solve the problems of the prior art, the printer external character registration memory control method according to the present invention employs a random access system in which a part of the memory area is used as the external character registration memory. The memory is provided with an address conversion table for specifying the start address of font data based on the value of a predetermined bit of the custom character code, and a counter for counting the number of unregistered custom characters or the number of registered non-registered characters. The font data registration area specified by the address conversion table is set, and the font data is stored in the order of registered characters from the end or the beginning of the area of the character registration memory.

(Function) When registering a custom character, a table address of the address conversion table is created based on the value of the specified bit of the custom character code, and the start address of the font data in the area of the custom character registration memory is specified corresponding to this table address. Ru. At this time, since the counter is counting the number of unregistered non-registered characters or the number of registered non-registered characters, the start address of the font data is specified in accordance with the count value.

As a result, the font data is stored sequentially from the end to the beginning of the area of the external character registration memory, or from the beginning to the end, regardless of the external character code at the time of registering the external character. Therefore, the problem of the prior art that the unregistered external character registration memory area is wasted can be solved.

(Example) Examples of the present invention will be described in detail below with reference to FIGS. 1 to 6.

FIG. 1 is a flowchart showing the control flow for registering and reading external characters according to this embodiment, and the processing within the dashed line frame is different from the conventional method. FIG. 2 is a diagram showing the circuit configuration of a printer to which this embodiment is applied. The printer shown in FIG. 2 includes a microprocessor 11 as a control circuit, an RO
M12, RAM13, timer (TIM) 14, input port 15, output port 16, address decoding circuit! ?
, a motor control section 18, and a print control section 19. A predetermined control program is stored in the ROM 12 in advance. The RAM 13 includes an address conversion table and a counter for the number of unregistered external characters, as well as an external character wall recording area which is the object of control in this embodiment. FIG. 3 is a diagrammatic representation of the indirect addressing method at the time of registering non-standard characters in this embodiment.

When registering external characters or reading fonts according to this embodiment, online input data is taken in from the input port 15 by executing the control program stored in the ROM 12 shown in FIG. 2, and the control flow shown in FIG. Control is performed accordingly.

First, the case of registering a non-standard character will be explained. Here, it is assumed that a series of data strings for registering non-standard characters as shown in FIG. 4 are received. If the allowable number of registered non-standard characters is K, the number of bits equal to the minimum integer S such that ≦2s is required to distinguish the species code, so it is possible to distinguish the code using the lower S bits of the non-standard character code. . If the value taken by this S bit is β, then β is in the range of 0 to (K-1). Third
As shown in the figure, if the first address of the address conversion table is M and one table is composed of 2 bytes (the address of the external character registration area generally requires 2 bytes because the capacity is several kilobytes or more), then The address is M~(-1 to M+2), and when using the above β to indicate the address of the address conversion table corresponding to the non-standard character code, M+2β is used.

Before receiving a series of data for registering private characters, the route was traveling along routes d and f (Fig. 1), but when the command for registering private characters among the data is received, the route branches to route a. , Proceed to step 4. In the judgment of step 4, check whether the data at address M+2β is <00)H (H indicates a hexa code), and thereby determine whether there has already been a registration with that code. . If it is not registered, this is because the address translation table has been cleared in the process after power-on (step l).

Branch to route b, and in step 5 move to address M+2β with N+
The value of αγ is written. Here, N indicates the start address of the external character registration area, α indicates the number of bytes required to configure one font, and γ is the value of the unregistered external character counter shown in Figure 5. In the process, γ= is set to -1. Also, D() indicates the data stored in the address in ().Next, in the process in step 6, after decrementing the unregistered external character number counter by 1, return to route c0.Next, proceed to step 7, and here The font data Di-Dα shown in FIG. 4 is written in the external character registration area in the process of
), Dl goes to address N+α(K-1), Dα
will be written to address 11 at N+α, which is the final address of the external character registration area. This completes the registration of one custom character, but since the unregistered custom character counter has been decremented by 1 in the process of step 6 in Figure 1, if you want to register another custom character next time, use the registration area for that font. is N+α(
K-2) address becomes N+α(K-1)-1 address. Similarly, each time a third, fourth, etc. private character is registered, the minus α address is set in the font registration area for the next private character.

This indicates that the private character registration area is filled up in order from the last memory block (one block is α byte) toward the first memory block, regardless of the type of private character code (value of β). Note that although this embodiment describes the case where the memory blocks are used by consolidating from the rear memory block to the first memory block, it is also possible to use the memory blocks by consolidating from the first memory block to the rear memory block.

Additionally, if you try to register the same custom character code again in order to modify the font data of a custom character code that has been registered once, the judgment in step 4 in Figure 1 will show that the code already corresponds to the code in the address conversion table. Since the start address of the font has been written, the route branches to C, and the font data is overwritten again from that address, and the correction is performed. This indicates that no matter how many times you register the same external character code, it will not affect others.

In this way, when all the necessary private character registrations are completed, the unused private character registration areas are from addresses N to (N0 α (γ + 1) - 1), and the remaining unused areas like the unused areas shown in Figure 6 are becomes.

Next, we will explain the case of reading registered font data. In this case, basically the same as the conventional indirect addressing method shown in FIG. Since the read data is the storage start address of the font, it is sufficient to read the α byte from there.As shown in FIG. After processing, the route returns to route f.

As described above, according to the method of the embodiment of the present invention, it is possible not only to leave unused private character registration memory continuously from the beginning or end of the private character registration area, but also to leave unused private character registration memory continuously from the beginning or end of the private character registration area. Since the address can be easily known, it is easy to use this unused memory for other expansion purposes. Assume that the standard receiving buffer is 2 bytes long and the external character registration area is 72 bytes per font and has 258 characters. Of these, 5
If only 6 characters are registered as external characters, 14 for 200 characters.
．． If the 4th byte becomes unused and all of this is used as a reception buffer, the 2nd byte will increase to 18.4 bytes at once, and this has great benefits. Also, set the final address of the receive buffer to “N+α(γ+
1) If you use the formula ``-1'', the receive buffer size will automatically increase the amount of unused registered characters, so set the receive buffer area externally every time the number of registered characters changes. There's no need to fix it.

(Effects of the Invention) As described in detail above, according to the present invention, unused character registration memory can be left continuously from the beginning or end of the character registration area, and the final address of the unused area can be It also has the advantage of making it easier to know. Therefore, the external character registration memory is effectively utilized, and unused memory can be used for expanding other functions.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the control flow of the method of the present invention, FIG. 2 is a configuration diagram of a printer to which the method of the present invention is applied, and FIG. 3 is an explanatory diagram schematically showing external character registration using the method of the present invention. , Figure 4 is a diagram showing an example of an online input data string when registering a private character, Figure 5 is a configuration diagram of an unregistered private character number counter, and Figure 6 is the use of the private character registration area when using the method of the present invention. Fig. 7 is a diagram showing the conventional semi-direct addressing method, Fig. 8 is a diagram showing the conventional indirect addressing method, and Fig. 9 is a diagram showing the conventional indirect addressing method. It is a figure which shows the usage state of a non-standard character registration area. 11... Microprocessor, 12... ROM. 13...RAM, 14...Timer, 15...Input board, 1B...
Output port, 17...address decoding circuit, 18
...Motor control section, 18...Print control section.

Claims (1)

[Scope of Claims] An address conversion table for specifying the start address of font data based on the value of a predetermined bit of a custom character code, in a random access memory in which a part of the memory area is used as a custom character registration memory; A counter for counting the number of unregistered non-registered characters or the number of registered non-registered characters is provided, and the font data registration area specified by the address conversion table is set according to the count information of the counter, and the font data registration area is set at the end or the beginning of the area of the non-registered character registration memory in the order of registration of the non-registered characters. A printer external character registration memory control method characterized in that font data is stored in order from .