JP3087481B2 - In-circuit emulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-circuit emulator, and more particularly to an in-circuit emulator having a control circuit for synchronously executing an external command.

[0002]

2. Description of the Related Art Conventionally, this kind of in-circuit emulator does not have a synchronization function, so that it has not been possible to operate in synchronization with a plurality of in-circuit emulators. Therefore, when performing synchronous debugging between microprocessors, such as when debugging a multi-microprocessor system, the target system incorporates hardware and software for communication between the processors into the target system for debugging.

Referring to FIG. 6, a target system A and a target system B are connected by a communication port, and a debug monitor incorporated in the target system communicates between the target systems via the communication port. Of information.

When it is desired to start the processing of the target system B in the state of the target system A, the debug monitor A notifies the communication port when detecting the state. The debug monitor B monitors the communication port and detects the state of the target system A.
The processing of the system B is started. Thus, the configuration is such that debugging is performed using hardware and software on the target system.

[0005]

SUMMARY OF THE INVENTION The above-described conventional in-
The circuit emulator requires communication hardware and software on the target system, which increases development and manufacturing costs that are not required for the original system functions. In addition, since the state is detected by software on the target, the state that can be detected is limited, and the overhead impairs the real-time property.

[0006]

An in-circuit emulator according to the present invention detects an external terminal supplied with an input signal, a signal level of the input signal or the presence or absence of a pulse, and starts execution of a debug command. -Circuit emulator having control circuit for controlling start and stop
The input / output terminal of the external terminal and the control circuit
AND with the output of the status detection circuit of the microprocessor bus
Is used as a debug interrupt signal .

[0007]

Further, the in-circuit Emi of the present invention
An external terminal for receiving an input signal;
Detects the signal level of the input signal or the presence or absence of a pulse, and
Controls the start and stop of bag command execution
In-circuit emulator with control circuit
The control circuit is configured to connect the input of the external terminal to the microprocessor.
The logical product with the output of the processor bus status detection circuit is
Use as a cycle extension (weight) signal
You can also.

Further, the in-circuit circuit of the present invention
The emulator has an external terminal for receiving an input signal,
Detects the signal level of the input signal or the presence or absence of a pulse
And start and stop the execution of debugging commands
-Circuit emulator with control circuit
In the above, the control circuit may connect the input of the external terminal to the
AND with the output of the state detection circuit of the microprocessor bus
Use as a bus release request (hold) signal
You can also.

[0010]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a connection diagram of an in-circuit emulator according to a first embodiment of the present invention.

The in-circuit emulator A1 connected to the target system A3 and the in-circuit emulator B2 connected to the target system B4 have synchronization signal terminals EVENT IN, EVENT.
Used by connecting at OUT.

FIG. 2 is an internal block diagram of the first embodiment . The emulation MPU 6 is connected to a memory space switching block 9 and a bus state detection block 7 via an MPU bus. The memory space switching block 9 includes a monitor memory 10 for processing a command for debugging and a target memory for executing a program of the target system.
The memory 11 is switched. The bus state detection block 7
A block for detecting a specific bus state, such as an address and data, monitors the bus state under conditions set during debugging and outputs a detection result. This event detection output is EVENT
OUT terminal 12 and program execution control block and A
Input to the ND gate. The EVENTIN terminal signal input 13 is ANDed with the EVENT OUT signal 12 and input to the program execution control circuit 8. The program execution control block 8 requests a debug interrupt to the emulation MPU 6 in accordance with the detected event, and generates a memory selection signal for switching a memory space.

The operation of this embodiment will be described with reference to FIG. 3 which is a state transition diagram when the first embodiment of the present invention is used.

When data = 55H is written to I / O address = 3FFFFH during execution of the program of target system A, the program of target system B is started from address = 0100H.

First, an in-circuit emulator A
Then, the setting of the bus state detection block is changed to I / O address =
EVENT OU with data = 55H write to 3FFFFH
Output to T. Then, the program of the target system A is executed. I / O address = 3FF during execution
EVENT when a write occurs on data = 55H in FH
OUT is output.

On the other hand, an in-circuit emulator B
In step 2, the bus state detection block 7 is set to all states, the contents of the interrupt processing are set to the return address of each register value (target system B program start address) = 100H, and the apparatus enters the interrupt wait state. When the EVENT IN from the target system A3 is input, an interrupt process is executed, and the target system B4 sets the address = 10
Execute the program from 0H.

Next, referring to FIG. 4 showing a block diagram of an in-circuit emulator according to a second embodiment of the present invention, this embodiment outputs an output 16 of the program execution control block 8 to a wait signal of the emulation MPU 6. WA
Connected to IT. Instead of the interrupt waiting state in the first embodiment, the EVENT IN input is waited for by extending the bus cycle. In this embodiment, there is no overhead due to the interrupt processing, and synchronization can be performed in bus cycle units.

Next, referring to FIG. 5, which shows a block diagram of an in-circuit emulator according to a third embodiment of the present invention, this embodiment outputs an output 17 of a program execution control block 8 to a hold signal of an emulation MPU. HO
It is connected to the LD, and releases the bus (waits for EVENT IN input in the hold state) instead of the interrupt wait state in the first embodiment. In this embodiment, there is no overhead due to the interrupt processing, and synchronization can be performed in instruction units.

[0020]

As described above, the in-circuit emulator according to the present invention is provided with a command execution synchronization circuit, so that two emulators can be provided without changing the hardware and software of the target system. Since the program synchronization and de-synchronization between the microcomputer systems described above can be intentionally set and changed, it is possible to easily reproduce the problem state caused by the program synchronization between multiple processors, which is difficult in normal evaluation, and to efficiently execute This has the effect of enabling debugging.

[Brief description of the drawings]

FIG. 1 is a circuit connection diagram of an in-circuit emulator according to a first embodiment of the present invention.

FIG. 2 is an internal block diagram of the first embodiment shown in FIG.

FIG. 3 is a state transition diagram when the in-circuit emulator according to the first embodiment of the present invention shown in FIG. 1 is used.

FIG. 4 is an internal block diagram of an in-circuit emulator according to a second embodiment of the present invention.

FIG. 5 is an internal block diagram of an in-circuit emulator according to a third embodiment of the present invention.

FIG. 6 is a circuit connection diagram of a conventional in-circuit emulator.

[Explanation of symbols]

 1 In-Circuit Emulator A 2 In-Circuit Emulator B 3 Target System A 4 Target System B 5 Synchronization Signal Terminal 6 Emulation MPU 7 Spring State Detection Block 8 Program Execution Control Block 9 Memory Space Switching Block 10 Monitor Memory 11 Target -Memory 12 EVENT OUT terminal 13 EVENT IN terminal 14 Buffer selection signal 15 Debug interrupt signal 16 WAIT signal 17 HOUD signal 21 In-circuit emulator A 22 In-circuit emulator B 23 Target system A 24 Target system B 25 For communication Port 26 Debug monitor

Claims (3)

(57) [Claims] An external terminal for receiving an input signal; detecting a signal level of the input signal or the presence or absence of a pulse;
Controls starting and stopping execution of debugging commands
In-circuit emulator with control circuit
And the control circuit is configured to connect the input of the external terminal
The logical product with the output of the processor bus status detection circuit is debugged.
Characterized in that it is used as an interrupt signal for
Circuit emulator. An external terminal for receiving an input signal;
Detects the signal level of the input signal or the presence or absence of a pulse.
Controls starting and stopping execution of debugging commands
In-circuit emulator with control circuit
And the control circuit is configured to connect the input of the external terminal
The AND of the processor bus status detection circuit output and the bus
Specially used as cycle extension (wait) signal.
An in-circuit emulator to feature. 3. An external terminal for receiving an input signal, and
Detects the signal level of the input signal or the presence or absence of a pulse.
Controls starting and stopping execution of debugging commands
In-circuit emulator with control circuit
And the control circuit is configured to connect the input of the external terminal
The AND of the processor bus status detection circuit output and the bus
It is used as an open request (hold) signal.
In-circuit emulator.