JPH0373011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an in-circuit emulator capable of simulating a target system using an in-circuit method.

(Prior Art) Debugging devices for debugging programs in a target system using an in-circuit method are well known. In one of these debugging devices, if the target CPU and the CPU on the debugging device side are different, resources such as registers of the target CPU are allocated to the CPU on the debugging device side, and the instructions of the target CPU are There are emulators that have the ability to extract a file, interpret its meaning, and perform operations corresponding to that meaning on the image on the target CPU side.

However, with conventional emulators of this type, when debugging a program for input/output devices (referred to as input/output I/O), it is necessary to connect the peripheral I/O devices to the CPU (central processing unit) board. It was possible to debug the /O drive program. Therefore, it is not possible to develop an I/O drive program without the actual device, and this is constrained by the fact that debugging of I/O software must be done after confirming the operation of the hardware. The software development process is dependent on the hardware, resulting in poor development efficiency.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an in-circuit emulator that can debug an I/O drive program without using an actual device.

(Means for Solving the Problem) In order to achieve such an object, the present invention provides an incircuit emulator that includes an emulation memory capable of emulating a user's input/output port space, and an input/output port space of a user's input/output device. It has a bus cycle counter that can count the time in bus cycle units of the target microprocessor, and a function that can replace the contents of the emulation memory based on the contents of this bus cycle counter, which is necessary for debugging. It is characterized in that it is equipped with a host CPU that performs various controls, etc., and can simulate the input/output of input/output equipment on the target side.

(Example) The present invention will be explained in detail below using the drawings. FIG. 1 is a block diagram showing an embodiment of an in-circuit emulator according to the present invention. In the figure,
The part 1 surrounded by the dotted line is the target, but in this application, it is not necessary to connect it because debugging can be performed without requiring the actual machine. A target microprocessor (μP) 2 is provided in the debugging device and executes a program stored in the emulation memory 5. 3 is a memory in which active programs are stored. The active program is a program that runs when the microprocessor 2 performs an active operation (for example, displaying register contents, temporarily stopping microprocessor operation, etc.).

Reference numeral 4 denotes an I/O emulation memory, which is a memory in which a user's input port and output port space can be specified. The I/O emulation memory 4 and emulation memory 5 can also be read or written by the host CPU 7. A bus cycle counter 6 counts bus cycles of the microprocessor 2. The CPU 7 presets the count value and reads the count value.
It is accessible from the side.

8 is a buffer, 9 is a bidirectional buffer, 10
1 is an address bus on the target microprocessor 2 side, 11 is a data bus on the target microprocessor 2 side, 12 is an address bus on the host CPU side, and 13 is a data bus on the host CPU side.

The operation in such a configuration will be explained next using a specific example as shown in FIG.

After writing data #φ1 to output port A, data is read from input port B, and if the value is #φφ, the value of output port A is set to #φφ.
Here, input port B and output port A are #φ1
#φφ after 100ms has passed since it was set to
shall be.

In such a case, the user first specifies in advance a numerical value corresponding to the time counter value of 100 ms using the keyboard input section (not shown) of the debugging device.
Host CPU 7 specifies an address via address bus 12 and buffer 8, and presets the value (here assumed to be 100 for convenience) into bus cycle counter 6 via data bus 13 and buffer 9.

The bus cycle A in the time chart in Figure 3 represents the operating state of the microprocessor, and as shown in the figure, when microprocessor 2 executes an instruction to output data #φ1 to output port A, the stub function is activated. do. A stub refers to a series of procedures based on a command string of a debugging device, and when the microprocessor 2 accesses the address instruction, the contents of the registered stub are executed. This stub can be set by the user, and stores a program that sets "φ1" in the I/O emulation memory 4 when the bus cycle counter value becomes zero.

The bus cycle counter 6 is a down counter, and counts down every time the bus cycle clock shown in FIG. It decreases to 99, 98, etc. The count value is monitored by the host CPU 8, and when the count value reaches zero, an instruction in the stub causes the I/O
The value in the O emulation memory 4 is rewritten to "φφ". This makes input port B #φ
100ms after 1 appears, it becomes #φφ.

Microprocessor 2 connects #φ1 to output port A.
After outputting , the data of input port B is monitored, and when it becomes #φφ (when 100ms have passed)
Set output port A to #φφ.

As described above, even if there is no actual I/O, I/O
O input/output data can be generated, thereby making it possible to simulate an I/O driver program without requiring an actual machine equipped with I/O equipment or the like.

Note that there may be a plurality of bus cycle counters 6, and the number of I/Os that can be assigned by the user can be specified as large as that number.

(Effects of the Invention) As explained above, according to the present invention, the I/O
space is allocated in emulation memory,
Operation similar to the actual device is possible, so I/O is possible without the actual device.
can increase the efficiency of software development.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an in-circuit emulator according to the present invention, and FIGS. 2 and 3 are time charts for explaining the operation. 2... Microprocessor, 3... Active program memory, 4... I/O emulation memory, 5... Emulation memory, 6... Bus cycle counter, 7... Host CPU, 8... Buffer , 9... Bidirectional buffer, 10, 12... Address bus, 11, 13...
...data bus.

Claims (1)

[Claims] 1. An in-circuit system that can debug a target program using an in-circuit method.
The emulator includes an emulation memory that can emulate the user's input/output port space, a bus cycle counter that can count the input/output time of the user's input/output device in bus cycles of the target microprocessor, and this bus cycle counter. The host CPU has a function of rewriting the contents of the emulation memory based on the contents of the emulation memory, and also has a host CPU that performs control necessary for debugging, and simulates the input/output of the input/output device on the target side. An in-circuit emulator that is characterized by being able to perform.