JP2001265621A - On-rom program debugging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a software breakpoint in a ROM area. SOLUTION: In the on-ROM program debugging system provided with a flash ROM where program instructions and addresses can be divided and erased/ written by the sector of a minimum unit, a RAM and a maintenance means for performing optional rewrite by the sector unit of the flash ROM, in the case of performing the program inside the flash ROM, the sector containing the instruction to be a point for activating a debugger is copied onto the RAM, a program control change instruction is rewritten and written to the flash ROM by using the maintenance means and thus, an operation is performed as the software breakpoint is set in the flash ROM area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a ROM debugging method for correcting an error in a program on a ROM without using an in-circuit emulator (ICE) or the like.

[0002]

2. Description of the Related Art A software breakpoint debugging method is known as one of the conventional program debugging methods. In the software breakpoint debugging method, a program instruction for setting a switch point is temporarily replaced with an instruction for changing program control, for example, an instruction for generating an interrupt (trap instruction).

According to this method, the area for setting a breakpoint is limited to a program developed in the RAM area, so that it was not physically possible to set a software breakpoint in the ROM area.

[0004] As an example, the contents described in Japanese Patent Application Laid-Open No. 9-288598 are shown. A program in a ROM is set as a target, a predetermined switch point of the program is referred to, and a table is referred to. There is provided a transfer control means for transferring control to a debugger. It has been proposed that a table manager that manages tables is provided as the transfer control means, and the table manager switches programs to be debugged, and selects and changes a plurality of different programs on the ROM to perform the debugger.

[0005]

However, according to this method, every time the program is executed, a large amount of time is required for the operation of comparing the reference tables. Further, it is necessary to embed a switch point which is a predetermined break point in a program instruction in advance.
After creating M, it is difficult to set a switch point at an arbitrary position. In addition, since the required number of switch points is embedded in the program instructions, the ROM capacity is extremely increased, resulting in an increase in the total program size, which limits the degree of freedom in design. Become.

It is an object of the present invention to solve these problems of the prior art and to enable setting of a software breakpoint in a ROM area.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a flash ROM capable of erasing and writing by dividing a program instruction and an address by a minimum unit sector.
ROM comprising OM, RAM, and maintenance means for arbitrarily rewriting the flash ROM in sector units.
In the above program debugging method, when a program in the flash ROM is programmed, a sector containing an instruction to be a point to start a debugger is stored in the R.
Copy on AM and rewrite program control change instruction,
By writing to the flash ROM using the maintenance means, the operation is performed as if a software breakpoint was set in the flash ROM area.

[0008]

An embodiment of the present invention will be described with reference to FIG.

FIG. 1 is an explanatory diagram for explaining a program debugging method according to the present invention.

In FIG. 1, reference numeral 1 denotes a flash ROM in which program data to be debugged is stored and data can be electrically erased and written. In this program, an instruction to be a point for starting a debugger is provided. Is included. The internal structure of the flash ROM 1 is shown in FIG. The inside of the ROM 1 shows the form of each sector, which is the smallest unit that can be divided and erased and written, and the flash ROM 1 is divided into several sectors (sector 1, sector 2,..., Sector n). I have. 3 indicates a storage format of the program instruction in each sector,
This shows how instructions corresponding to addresses are stored in address order.

Reference numeral 4 denotes a central processing unit (CPU), which is a control means for reading a program stored in the flash ROM 1 based on the address and executing the program. A sector on the flash ROM 1 containing an instruction to be a point for starting a debugger is stored in a rewritable memory space R
The original instruction, which is temporarily stored in the sector temporary storage area 7 of the AM 5 and rewritten by the instruction for changing the program control there, and the original address of the instruction on the flash ROM 1 are stored in the instruction temporary storage area in the RAM 5. 8 is stored. Reference numeral 6 denotes a maintenance unit that performs an operation of rewriting an instruction to be a point for starting debugging to an instruction for changing program control. Reference numeral 9 denotes an instruction bus for the CPU 4 to read a program command from the flash ROM 1.

Since the present invention is configured as described above, when it becomes necessary to debug a target program in the flash ROM 1, the present invention includes an instruction to be a point for starting the debugger in the flash ROM 1. By rewriting the sector in the sector temporary storage area 7 on the RAM 5 using the maintenance means 6 and writing the rewritten sector at the position of the erased sector in the flash ROM 1, the operation of the CPU 4 for reading the program in the flash ROM 1 is performed. When the program is executed, an instruction for changing program control written in advance is read from the flash ROM 1 and control is transferred to a debugger program that supports debugging, so that software necessary for debugging can be added to the program in the flash ROM 1 area. Wear break It can be operated as if you set the Into.

[0013]

As described above, according to the configuration and method of the present invention, instead of reading the original instruction from a predetermined breakpoint set in advance in the program on the memory, the program on the flash ROM is targeted. By rewriting a predetermined program control change command set in advance in the flash ROM by means of erasing / writing in sector units, the control of the program can be shifted to the debugger. It becomes possible to debug.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a program debugging method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flash ROM 2 ROM internal structure 3 Program instruction storage method 4 CPU 5 RAM 6 Maintenance means 7 Sector temporary storage area 8 Instruction temporary storage area 9 Instruction bus

Claims (1)

[Claims] 1. A flash RO that can be erased and written by dividing a program instruction and an address by a minimum unit sector.
M, a RAM, and a maintenance method for arbitrarily rewriting data in units of sectors of the flash ROM. In a method of debugging a program on a ROM, when a program in the flash ROM is to be executed, a point to be a starting point of a debugger should be set. The sector containing the instruction is
A program on the ROM, wherein the program control change instruction is rewritten and written to the flash ROM by using the maintenance means to operate as if a software breakpoint was set in the flash ROM area. Debug method.