JPH03238526A - Program controller - Google Patents

Abstract

PURPOSE:To add or change the program preliminarily written in a memory by discriminating whether the program is stored in a prescribed address of the memory or not and preliminarily programming the jump to the prescribed address at the time of discriminating that the program is stored in the prescribed address of the memory. CONSTITUTION:The memory incorporated in a CPU circuit 1 has the area from address '0000' (hexadecimal) to address '00FF' (hexadecimal) used as a RAM and has the area from address 00FF (hexadecimal) to address '10FF' (hexadecimal) used as a ROM, and a program A is preliminarily stored in this ROM area. The area from address 'C000' (hexadecimal) to address 'FFFF' (hexadecimal) is used for future storage of an additional program B. It is discriminated whether the program is stored in the prescribed address of the memory or not, and the jump to this prescribed address is preliminarily programmed when the program is stored there. Thus, the program recorded in the memory can be added or changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a program control device that allows additional programs to be written into an EPROM.

[Prior art] As a ROM that stores programs in a CPU circuit,
E P ROM (electrically pro
grammable read-only memory
) is common. When this EPROM is not in use, it is in an erased state where all FF (hexadecimal numbers) are stored, and when a program is written, it becomes "1" depending on the contents.
(binary number) is rewritten to "O" (binary number). For example, when rewriting FF (hexadecimal number) to A5 (hexadecimal number), 2.4.5.7 digits, such as FF (hexadecimal number) 11111111 (binary number) A5 (hexadecimal number) 10100101 (binary number) The "1" (binary number) in the eye is rewritten to "0" (binary number).

[Problems to be Solved by the Invention] Among EPROMs, one-time programming ROMs whose erasure windows are covered with mold cannot be erased. Therefore, in the one-time programming ROM once written as described above, the program cannot be added or changed even if the specifications are changed, and conventionally, the one-time programming ROM has been discarded.

The present invention has been made in view of the above problems, and an object of the present invention is to enable programs to be added to a one-time programming ROM.

[Means for Solving the Problems] In order to achieve this object, the program control device of the present invention has a one-time programming ROM as a memory that stores a program. The first step is to determine whether the program is stored in the specified location, the second step is to jump to the specified location if the program is stored in the specified location, and the second step is to jump to the specified location when the program is not stored in the specified location. A program is recorded that has a third step that moves on to the next step.

[Operation] In the program control device having the above configuration, it is determined whether a program is stored at a predetermined location in the memory, and
If a program is stored in a predetermined location in the memory, it is programmed in advance to jump to that predetermined location, so that the program recorded in the memory can be added or changed.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a program control device according to the present invention.

In FIG. 1, a CPU circuit 1 (one-chip microcomputer) receives signal input from a keyboard 3 and a select switch 33 via a path line 2 according to a program stored therein, and outputs signals from an output device 4 and a select switch 33.
Controls D31 and 32.

The memory built into the CPU circuit 1 is configured as shown in the memory map of FIG. oOoO (hexadecimal)
The area from address to ○OFF (hexadecimal) address is used as RAM. 0OFF (hexadecimal number) from address l0
The area up to address FF (hexadecimal number) is used as a ROM, and program A is stored in advance. C00O(16
The addresses from FFFF (hexadecimal) to FFFF (hexadecimal) will be used to store additional program B in the future. That is, from address l0FF (hexadecimal number) to FFFF (1
The addresses up to (hex) addresses are unused, and are initially in an erased state with all FFs (hexadecimal) stored therein.

Program A includes at least the steps shown in the flowchart of FIG. 3, for example.

These steps are inserted where additional programming is likely to be required. That is, C00O(16
In step 10), it is determined whether the address is FF (hexadecimal), and if it is FF (hexadecimal), the process moves to the next step (step 12). FF (hexadecimal)
If not, jump to address C000 (hexadecimal number) (step 11).

If no program is added, C000(1
Since the address (hexadecimal number) remains in the erased state where FF (hexadecimal number) is stored, the C00O (
When it is determined whether the address (hexadecimal number) is FF (hexadecimal number), the process immediately moves to step 12. Therefore, steps 10 to 12 do not have an adverse effect on program A.

Program A is configured as shown in FIGS. 4 and 5, for example. In this program 8, C0
It is determined whether the address 0O (hexadecimal number) is FF (hexadecimal number) (step 40), and if it is FF (hexadecimal number), the process moves to the next step (step 42). FF (
If the address is not (hexadecimal), it jumps to address C00O (hexadecimal) (step 41).

If program B has not been added, C000(
Since the address (hexadecimal number) remains in the erased state where FF (hexadecimal number) is stored, C00O is stored in step 40.
(Hexadecimal) When it is determined whether the address is FF (hexadecimal), the process immediately moves to step 42. Thereafter, it is determined whether the device (for example, an audio device) incorporating the circuit shown in FIG. 1 is in the playback mode (step 4).
3).

When it is determined that the mode is not the playback mode, the LED 32 is turned on and processing other than the playback mode is performed (step 44).

Once it is determined that the mode is the playback mode, the LED 32 is turned off and processing is performed as the playback mode (step 45).

FIG. 5 shows an interrupt or subroutine program in program A.

In FIG. 5, when an interrupt or a subroutine starts, a key scan of the keyboard 3 (step 50) is performed to determine whether or not the mode is playback mode (step 51). If the mode is playback mode, another key is captured (step 56) and the process returns to step 42 of program A (step 57).

If it is not the playback mode, it is determined whether the select switch 33 has been pressed (step 52).

If the select switch 33 is not pressed, another key is imported (step 56) and program A is selected.
The process returns to step 42 (step 57). If the select switch 33 has been pressed, it is determined whether the LED 31 is lit (step 53).

If the LED 31 is not lit, turn on the LED 31 (step 54) and then import another key (
step 56), return to step 42 of program A (
Step 57). If LED31 is lit, L
After turning off the ED 31 (step 55), another key is read (step 56), and the process returns to step 42 of program A (step 57).

If it becomes necessary to add or change a program to program A, the program B to be added or changed will be C00
It is written from address O (hexadecimal number) to address FFFF (hexadecimal number).

This program B starts from address C00O (hexadecimal) to F
When additional writing is performed up to address FFF (hexadecimal number), address C00O (hexadecimal number) becomes FF (16
(base number) will be changed to another operation code. If FF (hexadecimal number) exists as the operation code of CPU circuit 1, FF
An operation code other than (hexadecimal number) for a NOP instruction (instruction to do nothing) is written.

FIG. 6 shows that in Program A before the additions and changes shown in FIGS. 4 and 5, LEDs 31 and 32 were lit independently and independently of each other;
This shows an example of program B added to the flow when the specifications are changed so that the LED 31 is also turned off while the LED 31 is turned off.

In FIG. 6, when program B starts, LE
Determine whether D31 is lit (step 21
). If the LED 31 is lit, it is determined whether the LED 32 is lit (step 25). LE'
If D32 is lit, the process returns to step 12 of program A. If LED 32 is off, the RAM
After setting the LED memory variable provided in program A to n1pp and turning off the LED 31 (step 26), the process returns to step 42 of program A.

If it is determined in step 21 that the LED 31 is off, it is determined whether the LED 32 is on (step 22). If the LED 32 is off, the program returns to step 42 of program A. If the LED 32 is lit, it is determined whether the LED memory variable provided in the RAM 4 is 1''' (step 23).
If the ED memory variable is not ppVp, program A
Return to step 42. LED memory variable is #11##
If so, set the LED memory variable to II O##, turn on the LED 31 (step 24), and then return to step 42 of the program.

In this way, after program B is added and changed, program A always changes C0 from step 40 to step 41.
After jumping to address 0O (hexadecimal number) and executing program B, the process returns to step 42.

The program shown in FIG. 3 can be inserted into the interrupt processing of the CPU circuit 1, or can be inserted before or after the processing of the controller unit, such as inputting key human power.

Although the present invention has been described above using examples, various modifications are possible according to the technical idea of the present invention. For example, in the above embodiment, the number of additional programs B is ↓, but there are multiple memory areas for additional programs (for example, AOOO to AFFF (16
(hexadecimal) addresses, BOOO to BFFF (hexadecimal) addresses, cooo to CFFF (hexadecimal) addresses, etc.),
By inserting a plurality of steps shown in FIG. 3 into program A, it is possible to add a plurality of programs.

[Effects of the Invention] As described above, according to the program control device of the present invention,
We decided whether or not a program is stored in a specified memory location, and if a program is stored in a specific memory location, we pre-programmed the program to jump to that location. It becomes possible to add or change programs that have been written in advance.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a program control device according to the present invention, and FIG. 2 is a memory map showing the structure of an embodiment of the program control device according to the present invention.
3 to 6 are flowcharts illustrating the operation of one embodiment of the program control device according to the present invention. 1. CPU circuit, 2.--pass line, 3.. keyboard, 6.. output device.

Claims (1)

[Claims] One-time programming ROM that stores programs
In a program control device having a program controller as a memory, the memory includes a first step of determining whether or not a program is stored in a predetermined location of the memory, and a first step of determining whether a program is stored in a predetermined location of the memory; A program control device in which a program is recorded, which has a second step of jumping to a predetermined location, and a third step of moving to the next step when no program is stored in the predetermined location.