Data processing: structural design – modeling – simulation – and em – Emulation – Of peripheral device
Reexamination Certificate
1998-07-31
2001-07-17
Teska, Kevin J. (Department: 2123)
Data processing: structural design, modeling, simulation, and em
Emulation
Of peripheral device
C703S027000, C703S020000, C710S108000
Reexamination Certificate
active
06263305
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a software development tool and more particularly, to a software development supporting system of the Read-Only memory (ROM) emulation type and a ROM emulation apparatus that are designed for a microprocessor-based target system having a Peripheral Component Interconnector (PCI) bus, in which a target ROM is controlled by a ROM controller through the PCI bus under the control of a microprocessor.
2. Description of the Prior Art
A conventional software development supporting system of this sort is disclosed in the Japanese Non-Examined Patent Publication No. 64-9542 published in January 1989.
This conventional system includes a ROM emulator designed to be electrically connected to a host computer. This ROM emulator is equipped with a user Random-Access Memory (RAM) for storing a user program, a trace RAM for storing a trace program, and a controller for controlling the user and trace programs and the emulation procedure. Further, this ROM emulator has a probe for electrically connecting this ROM emulator to a user system or target system on which a Central Processing Unit (CPU) and a target ROM are mounted. The probe of the ROM emulator is designed to be electrically coupled with the target ROM.
When a user program is produced or developed in the host computer, this user program is transmitted to the user RAM mounted on the ROM emulator and stored therein. Then, the user program in the user RAM is traced on the ROM emulator using the trace program stored in the trace RAM under the control of the CPU and the controller. The ROM emulator emulates the operation of the target ROM (i.e., the program stored in the target ROM) mounted on the user system.
In the above-described conventional software development supporting system disclosed in the Japanese Non-Examined Patent Publication No. 64-9542, there is a following problem.
Specifically, to electrically connect the ROM emulator to the user system or target system, the probe of the ROM emulator needs to be coupled with a ROM socket fixed on the target system for mounting the target ROM. This means that a ROM socket is necessarily mounted on the target system for electrical coupling of the ROM emulator. Therefore, this conventional software development supporting system is unable or very difficult to be electrically connected to a user or target system in which a target ROM is directly fixed onto a system board with solder and no ROM socket is equipped for the target ROM.
For example, to electrically connect this conventional software development supporting system to the user or target system, a ROM socket needs to be temporarily mounted on the system board after the target ROM isolated onto the system board is removed therefrom.
A dedicated ROM socket for the ROM emulator may be provided on the user system in advance. In this case, however, this dedicated ROM socket will causes a disadvantage that the size and cost of the system board is increased.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a software development supporting system of the ROM emulation type that facilitates the electrical connection to a target system equipped with no ROM socket.
Another object of the present invention is to provide a software development supporting system of the ROM emulation type that is able to be electrically connected to a target system through a PCI bus.
Still another object of the present invention is to provide a ROM emulation apparatus that is applicable to ROM emulation of a target system equipped with a PCI bus.
The above objects together with others not specifically mentioned will become clear to those skilled in the art from the following description.
According to a first aspect of the present invention, a software development supporting system is provided, which is comprised of a ROM controller electrically connectable to a PCI bus of a target system, a ROM emulator for emulating an operation of a target ROM mounted on the target system, and a host computer electrical connected to the ROM emulator.
The ROM controller receives a control signal for controlling the target ROM, in which the control signal is transmitted through the PCI bus of the target system. The ROM controller transfer the received control signal to the ROM emulator, thereby controlling the ROM emulator.
With the software development supporting system according to the first aspect of the present invention, the ROM controller is electrically connectable to a PCI bus of a target system, and a control signal for controlling a target ROM of the target system is transmitted through the PCI bus to the ROM controller. Also, the ROM controller receives the control signal and then, transfers the received control signal to the ROM emulator, thereby controlling the ROM emulator. Thus, the ROM emulator performs an emulation operation of the target ROM using the control signal transmitted through the PCI bus.
As a result, even if a target system is equipped with no ROM socket, electrical connection to this target system is readily realized by electrically connecting the software development supporting system according to the first aspect to the PCI bus of the target system.
This means that the software development supporting system according to the present invention is able to be electrically connected to the target system through the PCI bus.
In a preferred embodiment of the system according to the first aspect of the present invention, the ROM controller is designed to output an access assertion signal to the PCI bus before a ROM controller of the target system outputs an access assertion signal to the target ROM. Thus, the ROM emulator serves to emulate the target ROM using the control signal.
In this case, there is an additional advantage that the ROM emulator is readily driven with the use of the control signal for the target ROM.
In another preferred embodiment of the system according to the first aspect of the present invention, the ROM controller and the ROM emulator are mounted on a same emulation board. The emulation board is designed to be applicable to a PCI slot electrically connected to the PCI bus.
In this case, there is an additional advantage that the software development supporting system according to the first aspect of the present invention can be readily attached to the target system on use.
In still another preferred embodiment of the system according to the first aspect of the present invention, the ROM controller is mounted on an emulation board and the ROM emulator is not mounted on the emulation board. The emulation board has a ROM socket for electrical connection to the ROM emulator. The ROM emulator is electrically connected to the ROM controller through the ROM socket.
In this case, there is an additional advantage that a conventional ROM emulator is applicable to the software development supporting system according to the first aspect of the present invention.
According to a second aspect of the present invention, a ROM emulation apparatus is provided, which is comprised of a substrate having a first input/output (I/O) interface for electrically connection to a PCI bus of a target system and a second I/O interface for electrically connection to an external host computer, a ROM controller mounted on the substrate and electrically connected to the first I/O interface, and a ROM emulator for emulating an operation of a target ROM mounted on the target system.
The ROM controller receives a control signal for controlling the target ROM through the first I/O interface of the substrate, in which the control signal is transmitted through the PCI bus of the target system. The ROM controller transfers the received control signal to the ROM emulator, thereby controlling the ROM emulator.
With the ROM emulation apparatus according to the second aspect of the present invention, because of substantially the same reason as that of the software development supporting system according to the first aspect of the present invention, this appara
McGuireWoods LLP
NEC Corporation
Phan Thai
Teska Kevin J.
LandOfFree
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