JPH0481939A - Control system for microcomputer - Google Patents

Abstract

PURPOSE:To eliminate the need for executing a program prepared separately for accessing an internal register at the time of debug of the program by stopping temporarily the processing, accessing directly the internal register from the outside through a signal line connected to the outside, and also, restarting the processing by a value of the accessed internal register. CONSTITUTION:When a microcomputer 1 is processing is program, the processing operation is stopped temporarily by a signal inputted from a control signal line 7, and based on an address signal on an address bus 8, a decoder 16 specifies one register in internal registers 2 - 5. The contents of this register are read out to a data bus 9 by a control signal, and in the outside, the contents of this register are confirmed, and debug, etc., are executed. The restart of the program is started from the value of this register. In such a way, it is unnecessary to execute the program prepared separately for accessing the internal register, and in a state that the processing is stopped temporarily, the value of the internal register can be accessed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method for a microcomputer.

[Conventional technology]

FIG. 3 is a diagram showing the configuration of a conventional microcomputer and its connection with an interrupt controller.

In the figure, 1 is a microcomputer, 2 is an accumulator which is an internal register of the microcomputer, 3 is an index register, 4 is a program counter, and 5 is a stack pointer.

Reference numeral 6 indicates a controller for controlling the operation of the microcomputer, 7 a control signal line, 8 an address bus, and 9 a data bus. Reference numeral 10 denotes an interrupt controller, which arbitrates the priority order of interrupts when there are a large number of interrupts.

The microcomputer 1 shown in FIG. 3 is equipped with a function to temporarily stop processing in response to an external hold request, for example, and has instructions for accessing each of the internal registers 2 to 5. ing. Furthermore, it has an interrupt function for switching processing in response to interrupt requests.

FIG. 4 is a diagram showing the flow of processing when debugging a program. 11 is a program to be debugged; 12 is a part where the value of an internal register of the microcontroller is desired to be known or changed; 13 is a timing for inputting an interrupt request; and 14 is a program that accesses an internal register. 15 represents the processing flow of the microcomputer 1.

Next, the operation will be explained.

To debug program 11, program 11
At the point in time when executing a part 12 where the values of the internal registers 2 to 5 above are to be known or a part 12 where the values are to be changed, an interrupt request is input from the outside at timing 13 to switch the processing. Next, after jumping to a program 14 for accessing a separately prepared internal register and executing it, the program returns to the original program 1 and switches the processing.

[Problem to be solved by the invention]

In the conventional microcomputer 1 as described above, in order to access each of the internal registers 2 to 5, it is necessary to execute an instruction corresponding to the access.
~5 cannot be accessed.

In the present invention, when debugging a program, even if you want to know the value of an internal register or change the value, there is no need to execute a separate program that accesses the internal register by interrupt, and the process can be temporarily stopped. The purpose is to obtain a microcomputer that can access the values of internal registers in any state.

[Means to solve the problem]

In this invention, a plurality of registers 2 to 5 are provided, and control signal lines 7. Address bus 8, data bus 9. In the microcomputer l connected to the outside by
.

[Effect]

In this invention, while the microcomputer 1 is processing a program, the processing operation is temporarily stopped by a signal input from the control signal line 7, and the decoder 16 reads the - register based on the address signal on the address bus 8. Identify.

The contents of this register are read out to the data bus 9 using a control signal, and the contents of this register are checked externally for debugging and the like. Resuming the program starts from the value of the register.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a microcomputer, 2 is an accumulator which is an internal register of the microcomputer,
3 is the index register, 4 is the program counter,
5 indicates a stack pointer. Reference numeral 6 indicates a controller that controls the operation of the microcomputer, and 16 indicates a decoder that specifies an internal register from an externally given address during a temporary suspension of processing. Reference numeral 7 indicates a control signal line, 8 an address bus, and 9 a data bus.

FIG. 2 is a flowchart of processing when debugging the above program. 11 is the program to be debugged; 12 is the part where you want to know or change the value of the internal register of the microcomputer 1; 13 is the timing to temporarily stop the execution of the program; and 15 is the flow of processing in the microcomputer 1. .

Debugging of the program of the microcomputer 1 according to the present invention is performed as follows.

When the microcomputer l accesses the internal registers 2, 3, 4, and 5 on the program and processes the part 12 whose contents are desired to be known or modified, the process is temporarily stopped via the control signal line 7. A request signal a is input from the outside. Upon receiving this request signal a, the controller 6 temporarily stops the processing of the microcomputer 1 at timing 13, and activates the decoder 16.

The decoder 16 receives data A from the address bus 8.
The corresponding internal register to be accessed is specified by the DD, and reading or writing is determined by the control signal a input from the control signal m7. - The contents of the internal registers required during the time stop are read or written via the data bus 9. After accessing the internal register in this manner, the processing pause request signal a inputted from the control signal line 7 is released, and the original program processing is resumed.

As is clear from FIG. 2, in the microcomputer according to the present invention, when debugging a program, there is no need to execute a program that accesses internal registers by interrupts.

In the above embodiment, the internal registers are an accumulator, an index register, a program counter, and a stack pointer, but the same effect can be obtained even in a microcomputer with a different internal register configuration.

〔Effect of the invention〕

As explained above, in the microcomputer control method according to the present invention, processing is temporarily stopped, internal registers are directly accessed from the outside through signal lines connected to the outside, and processing is performed using the values of the accessed internal registers. Now, when debugging a program, if you want to know the value of an internal register or change the value, you can use an interrupt to restart the process without having to run a separate program that accesses the internal register. All you have to do is pause.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a microcomputer according to an embodiment of the present invention, FIG. 2 is a flowchart of processing when debugging a program of a microcomputer according to an embodiment of the present invention, and FIG. A block diagram showing the configuration of a conventional microcomputer and a connection state with an interrupt controller is shown in FIG. 4, and FIG. 4 shows a flowchart of processing when debugging a conventional computer program. ■ is a microcomputer, 2 is an accumulator, 3 is an index register, 4 is a program counter, 5 is a stack pointer, 6 is a controller, 7 is a control signal line, 8
is an address bus, 9 is a pig bus, 10 is an interrupt controller, 11 is a program to be debugged, 12
13 represents an interrupt timing, 14 represents a program executed by an interrupt, 15 represents a processing flow, and 16 represents a decoder. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Patent Attorney Jun Miyazono

Claims (1)

[Claims] In a control system for a microcomputer that has a plurality of registers and is connected to the outside through a control signal line, an address bus, and a data bus, any one of the registers is controlled by an address given from the address bus. 1. A control system for a microcomputer, characterized in that a decoder is provided to specify the register, the processing operation is temporarily stopped, and the register is accessed through the control signal line and the data bus.