JPH10283173A - Program write system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform on-board write at a low cost with excellent work efficiency by providing a means for packaging or connecting an ROM storing a boot program means for writing a firmware program in the ROM through a microcomputer. SOLUTION: In the state of packaging the ROM 6 storing a boot program, a personal computer 4 is activated. At the time, the personal computer 4 and the microcomputer 1 are connected through terminals 14 and 15 and an interface 12. Then, immediately after the microcomputer 1 is activated, a processing for reading serial data (firmware program) from the personal computer 4 by a program for booting stored in the ROM 6 storing the boot program and writing it in the ROM 2 for storing the firmware program is performed. After write is ended, the ROM 6 storing the boot program is detached from the terminal 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an on-board writing method for a firmware program in an electronic device.

[0002]

2. Description of the Related Art FIGS. 2 and 3 are block diagrams showing a conventional on-board writing method. FIG. 2 shows a method of directly writing data from an external writing device to a ROM storing a firmware program via address and data signal lines.

FIG. 3 shows an example in which a boot program is stored in a program storage (ROM) area in a microcomputer in advance. FIG. 3 shows a firmware program loaded into the microcomputer as serial data from outside (in this case, a personal computer) according to the boot program in the microcomputer.
This is a method of storing in OM.

In FIGS. 2 and 3, 1 is a microcomputer, 2 is a ROM for storing a firmware program, 3 is a device peripheral circuit, 4 is a personal computer, and 5 is a firmware for directly writing the firmware program to the ROM 2 for storing firmware. , A boot ROM, 7 an address bus, 8 a data bus, and 9 an R for storing firmware.
A control signal given to the OM, a control signal given to the device peripheral circuit, a control signal given to the boot ROM,
Denotes a serial transfer interface, 13 denotes a control signal supplied from a control circuit for directly writing to the ROM 2 storing firmware to the microcomputer, and 14 denotes a boot program area in the microcomputer 1.

The method shown in FIG. 2 requires externally a write adapter (ROM writer, etc.), a multi-core connection cable and a multi-core connection connector, and requires a lot of time to prepare for writing. there were. Therefore, in the case of a product of a small lot or another kind, there is also a disadvantage that the connection is frequently changed and the manufacturing efficiency is reduced. When writing firmware to many ROMs, the connection of these jigs is RO
There is also a disadvantage that the number of M is required.

In the method shown in FIG. 3, a boot program for writing firmware into the microcomputer 1 itself must be written in advance (boot program area 14) and then mounted. There is a drawback that the work process enters and the work process becomes complicated. Another drawback is that a conversion adapter for connecting the ROM writer and the microcomputer is required to write the program into the microcomputer. Further, the microcomputer must have a ROM area for storing a boot program, and the price of such a microcomputer is RO
There was a drawback that it was more expensive than a microcomputer without the M area.

[0007]

SUMMARY OF THE INVENTION In order to solve these disadvantages, the present invention realizes on-board writing with good work efficiency and at low cost.

[0008]

According to the present invention, in order to attain the above object, the ROM (having a boot program) is provided only in an on-board writing operation in an area where a ROM having a boot program can be mounted in advance. A firmware program that is mounted and externally serially loaded into the microcomputer according to the boot program is written into the ROM according to the boot program.

As a result, a dedicated jig as shown in FIG. 2 is not required, and an inexpensive microcomputer without ROM can be used without using an expensive microcomputer with a built-in ROM as shown in FIG. An on-board writing function can be provided with a simple configuration.

After writing, ROM for boot program
There is no problem if you remove (because a normal operation does not require a boot program).

There is also an advantage that writing cannot be performed without a ROM for a boot program, so that writing is not erroneously performed and a program writing error can be prevented.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a block diagram showing one embodiment of the present invention.

1 is a microcomputer, 2 is a ROM for storing firmware, 3 is a device peripheral circuit, 4 is a personal computer, 6 is a ROM for storing a boot program, 7 is an address bus,
8 is a data bus, 9 is a ROM for storing firmware
10 is a control signal applied to the peripheral circuits of the device, 11 is a control signal applied to the ROM 6 storing a boot program, and 12 is a serial transfer interface.

First, a firmware program is stored in a ROM
2 will be described. In this state, the personal computer 4 is started while the ROM 6 storing the boot program is mounted. At this time, the personal computer 4 and the microcomputer 1
Are connected via terminals 14 and 15 and an interface 12. Immediately after the microcomputer 1 is started, a process of reading serial data (firmware program) from the personal computer 4 by the boot program stored in the ROM 6 storing the boot program and writing the serial data (firmware program) into the ROM 2 storing the firmware program is performed.
At this time, at the same time, the control signal 10 for notifying the ROM 2 of the write processing by the control signal 9 is transmitted to the ROM 2.
2 notifies that the writing process is being performed, and the peripheral circuit 3 operates carelessly so as not to affect the writing process. After the writing is completed, the ROM 6 storing the boot program is removed from the terminal 16. R that stores the boot program even if microcomputer 1 starts after removal
The microcomputer 1 determines that the OM 6 is not connected,
The process of writing the firmware program into the ROM 2 is not performed, and the device operates thereafter according to the firmware program in the ROM 2.

When the firmware program is revised, the microcomputer 1 is started again with the ROM 6 storing the boot program mounted thereon. Similar to the operation described above, the microcomputer 1 uses the RO storing the boot program.
Detecting that M6 has been implemented, a process of writing the revised firmware program from the personal computer 4 to the ROM 2 through serial data is performed. The ROM 6 storing the boot program may be mounted instead of being connected via the terminal 16.

[0017]

As described above, according to the present invention, since only a boot ROM is mounted in advance and a personal computer is connected to a serial interface and then the apparatus is started,
Preparation time for writing can be reduced. In addition, a dedicated multi-core connection cable and multi-core connection connector for writing are not required, and writing equipment can be realized at low cost. Further, since there is no need to write a boot program in the microcomputer in advance, there is an advantage that it can be realized by an inexpensive microcomputer without a built-in ROM. Furthermore, there is no step of writing the boot program in the microcomputer after the arrival, and the number of working steps can be reduced. Therefore, there is an advantage that the device can be manufactured in a shorter time than when a boot program is written and mounted in a microcomputer.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional writing method.

FIG. 3 is a block diagram showing a conventional writing method.

[Explanation of symbols]

1: microcomputer, 2: ROM for storing firmware,
3: device peripheral circuit, 4: personal computer, 5: control circuit for directly writing in ROM 2 for storing firmware, 6: boot ROM, 7: address bus, 8: data bus, 9: storing firmware Control signal given to ROM, 10: control signal given to device peripheral circuits, 1
1: a control signal given to a boot ROM, 12: a serial transfer interface, 13: a control signal given to a microcomputer from a control circuit for directly writing in a ROM 2 storing firmware.

Claims (1)

[Claims] 1. A method for writing a firmware program into a ROM without removing a ROM and a microcomputer from the electronic device, the firmware storing a firmware program of an electronic device operating by a program processing. And a means for mounting or connecting a ROM storing boot program means for writing the firmware program into the ROM via the ROM.