JPS6376023A - Microprocessor - Google Patents

Abstract

PURPOSE:To easily produce an in-circuit emulator (ICE) by switching an address space in a target system to an address space in the ICE when an execution address of a program reaches an expected address. CONSTITUTION:When the execution address of the program reaches a brake point, a control circuit 3 outputs an interruption signal to a microprocessor (MPU)2 through an interruption line 6. Recognizing the interruption, the MPU2 interrupts the execution of the program and transfers the execution to a subroutine in an interruption processing program. In the interruption processing subroutine, the MPU2 outputs an address control signal to a RAM14 and an address decoder 5 through an address control line 7 to inhibit access to the RAM14 and permit access to a RAM4. Thus, the address space is switched from the address space in the target system 11 so that in the in-circuit emulator (ICE)1. Thus, the debugging ICE can be easily produced.

Description

[Detailed Description of the Invention] (Summary) The present invention is aimed at making it possible to easily produce a so-called in-circuit emulator (ICE) that is necessary for debugging the hardware and software of a device using a microprocessor. , has a function of switching the address space from the address space of the target system to the address space of the in-circuit emulator when the execution address of the program in the in-circuit emulator or the target system to be debugged reaches a predetermined address. It is a microprocessor.

(Field of Industrial Application) The present invention relates to a microprocessor that allows easy production of an in-circuit emulator for debugging a device using the microprocessor.

Debugging devices using microprocessors has traditionally been done using oscilloscopes, etc. because of the complexity of their operations, and because the microprocessor is mounted in a package, so it is not possible to directly see the internal logic state. Debugging is difficult, and a debugging tool called an in-circuit emulator is used. This in-circuit emulator emulates the operation of a microprocessor, stops the operation at any time, and analyzes the internal logic state, thereby providing the ability to debug the so-called target system.

[Conventional technology]

Conventionally, when creating an in-circuit emulator, eight-ware is required to replace the operation of a microprocessor. I was making a circuit emulator.

(Problem to be Solved by the Invention) However, in such conventional in-circuit emulators, the microprocessor was not originally designed with the function of an in-circuit emulator in mind, so it is difficult to create an emulator using a microprocessor. In this case, it was not possible to completely emulate the original operation, and a complex external control circuit was required.

Furthermore, when outputting the internal logic state of a microprocessor to the address space of an in-circuit emulator at any given time, this control also requires a large amount of hardware and complicated software, which makes it difficult to develop an in-circuit emulator. It took a huge amount of time.

[Means for solving problems]

In order to make it possible to easily produce an in-circuit emulator, the present invention provides an in-circuit emulator that when the execution address of a program in a target system reaches a predetermined address, an address space is imported from the address space of the target system. We decided to equip the microprocessor with a function to switch to the address space of the circuit emulator.

(Function) According to the microprocessor having such a configuration, when the execution address of the program in the target system reaches a predetermined address, the address space is changed from the address space of the target system to the address space of the in-circuit emulator. It becomes possible to switch instantly.

(Embodiment) The figure shows one embodiment of the present invention, and specifically is a block diagram of an in-circuit emulator 1 using a microprocessor and a target system 11 to be debugged.

First, let's look at the in-circuit emulator l.
2 is a microprocessor in one embodiment of the present invention. 3 is a control circuit that outputs an interrupt signal to the microprocessor via a dedicated interrupt line 6 when the execution address in the target system 11 reaches a predetermined address.

When the microprocessor 2 recognizes the interrupt signal from the control circuit 3, the microprocessor 2 outputs an address control signal via the address system [17] to access the RAM 14 as an address space in the target system 11, which will be described later. The main memory is switched from RAM 4 to RAM 4, which serves as the address space of the in-circuit emulator 1. The microprocessor 2 applied to the in-circuit emulator 1 has internal wiring (so-called bonding wiring) for the interrupt line 6 and address control line 7, or does not perform internal wiring when supplied to general users. 9 is address bus, 10
are data buses, and these buses 9.10 contain microprocessors 2. A control circuit 3 is connected thereto, and a RAM 4 serving as the main memory of the microprocessor 2 is further connected via an address decoder 5.

Note that 8 is a user interrupt line for accepting user interrupts.

Next, regarding the target system 11, reference numeral 12 is a microprocessor having the same configuration as the microprocessor 2, but an interrupt line 6. Internal wiring corresponding to address control line 7 is not provided. Further, this microprocessor 12 can be removed from the socket cap in advance when the target system is debugged. 13 is a ROM that stores a program for the microprocessor 12 in the target system 11, and 14 is a RAM serving as a main memory.

15 is an address decoder. This target system 11 has an address bus 9. from the in-circuit emulator 1. A data bus IO is wired, for example, via a flat cable.

The address control line 7 is wired to the RAM 14 and the address decoder, and when an address control signal is output to the address control IIa7, access to the RAM 14 is prohibited and only access to the RAM 4 is permitted. There is.

The operation of the in-circuit emulator 1 and the target system 11 manufactured using the microprocessor 2 having such a configuration will be explained.

It is assumed that the microprocessor 12 has been removed from the socket etc. in advance, and the program for the target system 11 is stored in the ROM 13. Furthermore, when the execution address of the target system reaches a predetermined address from, for example, a keyboard device (not shown), an address corresponding to a so-called breakpoint is preset in the control circuit 3 via the microprocessor 2. do.

In such a state, the microprocessor 2 calls the program stored in the ROM 13 via the address bus 9 and the data bus 10, sequentially performs arithmetic processing, etc., and transfers the processing results to the RAM via the data bus IO.
14 predetermined addresses. By sequentially performing such processing, when the execution address of the program reaches the breakpoint, the control circuit 3
outputs an interrupt signal to the microprocessor 2 via the interrupt line 6. Therefore, when the microprocessor 2 recognizes the interrupt, it interrupts the execution of the program and moves on to the subroutine of the 1-interrupt processing program.

In the interrupt processing subroutine, the microprocessor 2 first sends an address control signal to the RAM 1 via the address control line 7.
4 and the address decoder 5, the RAM
Access to RAM 4 is prohibited, while access to RAM 4 is permitted. In this way, the microprocessor 2 switches the address space from the address space of the target system 11 to the address space of the in-circuit emulator l. Next, the microprocessor 2 stores logical information such as internal registers in the RAM 4 of the in-circuit emulator l, and Wait in routine. Then, the operation module analyzes the information dumped into the RAM 4 to proceed with debugging the target system 11.

As a method for switching the address space, automatic switching by hardware or a predetermined switching command may be used.

(Effects of IJI) According to the present invention, when the execution address of the program in the target system reaches a predetermined address, the address space is switched from the address space of the target system to the address space of the in-circuit emulator. Because it is a microprocessor, the external control circuit is much simpler than Y3 and M! This can be realized with a j configuration, and an in-circuit emulator for debugging can be easily produced.

[Brief explanation of the drawing]

The figure is a block diagram of an in-circuit emulator using a microprocessor and a block diagram of a target system according to an embodiment of the present invention. 2.12-...Microprocessor 3-@Control circuit 6...Interrupt line 7...Address control line 4.14-RAM

Claims (1)

[Claims] A microprocessor that switches an address space from an address space of the target system to an address space of an in-circuit emulator when the execution address of a program in the target system reaches a predetermined address.