JPH04305783A - Microcomputer - Google Patents

Abstract

PURPOSE:To recognize the data contents of a register at real time even in the operation of a microcomputer and to improve the efficiency of program development by providing the microcomputer with an address buffer and a data buffer for outputting address information and write data at the time of writing data in the register or a data memory. CONSTITUTION:At the time of executing data writing in the register 1 through a prescribed write instruction signal 101 in the microcomputer having the microcomputer controlling register 1 or a data memory, write address information and write data information for the register 1 are outputted from respective buffers 2, 3 to the outside through the control action of the signal 101.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer, and more particularly to a microcomputer used for developing programs.

0002

2. Description of the Related Art Conventionally, some microcomputers of this type have internal programs and control data for controlling the microcomputer. FIG. 3 is a partial block diagram showing relevant parts of the conventional microcomputer. As shown in FIG. 3, registers 10 are provided corresponding to address bus 205 and data bus 206 for register designation. Note that this register 10 is
It may be replaced by data memory.

When the content of the control program built into the microcomputer is to write to or read from the register 10, the address bus inside the microcomputer specifies the register to be written to/read from. , write/read data is input/output using an internal data bus.

Further, as an example of a case where a control program and control data are stored outside a microcomputer, there is a microcomputer shown in the partial block diagram of FIG. 4. As shown in FIG. 4, there is an address bus 207 for external control program and data access, a buffer 11 for addresses that is released depending on the execution of instruction cycles and external data access instructions, and registers. 12, and a data buffer 13 having bidirectional characteristics that is opened in accordance with execution of an instruction cycle and an external data access command. Here, register 12 may be replaced by a data memory.

In a microcomputer, in order to read a predetermined control program, the instruction cycle external access signal 103 specifies the read destination through the buffer 11 in accordance with the instruction cycle, and has an interface time with the outside. Thereafter, predetermined data is taken into the microcomputer via the bidirectional buffer 13. Even if the executed instruction is an instruction that accesses the outside, the read destination is specified through the buffer 11, and after it has had time to interface with the outside, it is transferred to the inside of the microcomputer through the bidirectional buffer 13. Data is imported to.

[0006]

[Problems to be Solved by the Invention] In the conventional microcomputer described above, in the process of developing a control program for the microcomputer, the address bus that specifies the registers or data memory inside the microcomputer is connected to the outside of the microcomputer. Since the microcomputer is not connected, it has the disadvantage that the contents of the microcomputer's internal registers or data memory cannot be viewed from the outside while the control program is being executed continuously in real time. .

[0007]

[Means for Solving the Problems] A microcomputer of the present invention has a register or data memory for controlling the microcomputer, and the microcomputer writes data to the register or data memory via a predetermined write command signal. When writing is performed, an address output buffer outputs write address information corresponding to the register or data memory to the outside of the microcomputer under the control of the write command signal; a data output buffer that outputs write data information to the register or data memory to the outside of the microcomputer under the control of the write command signal when writing data to the register or data memory;
It is composed of:

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a partial block diagram showing the register (or data memory) portion included in a first embodiment of the present invention. As shown in FIG. 1, the register portion of this embodiment includes a register 1 and buffers 2 and 3 corresponding to an address bus 201 and a data bus 202. The address bus 201 is a bus that specifies the write/read destination of data for register 1, and the buffer 2 is a bus that specifies the write destination of register 1 in the microcomputer when a write instruction is executed for register 1. This is an output buffer for outputting an address to the outside via the external connection terminal 51. Further, the buffer 3 is a data buffer for outputting write data to the register 1 to the outside via the external connection terminal 52 when a write command is executed in the microcomputer.

Next, the operation will be explained. When a microcomputer executes a write command to register 1, the data on data bus 202 is
It is written to the specified register 1 via the address bus 201, and is also written to the data output buffer 3 via the write command signal 101 for the register 1.
The data written to the register 1 is output to the outside via the external connection terminal 52, and at the same time, the data written to the register 1 is outputted by the address output buffer 2 via the write command signal 101. address information is output to the outside via the external connection terminal 51. Through this series of write operations, the microcomputer
Even when a real-time control program is being executed continuously, changes in the data contents in the register 1 inside the microcomputer can be observed from the outside.

[0011] In the above explanation, the operation was explained in the case of a register included in a microcomputer, but even if data memory is replaced in place of this register, the same operation will not be performed. Needless to say.

FIG. 2 is a partial block diagram showing the register (or data memory) portion included in a second embodiment of the invention. As shown in FIG. 2, the register portion of this embodiment includes register 4 and buffers 5 to 4 corresponding to address bus 203 and data bus 204.
8 and an AND circuit 9. Here, buffer 5 is a buffer for outputting address and data;
Buffer 6 is an address/data input/output buffer with bidirectional characteristics, and buffers 7 and 8 are data input/output buffers with bidirectional characteristics.

In the microcomputer, when a write instruction to register 4 is executed, data bus 2
The data on address bus 2 is transferred via write command signal 102 to bidirectional buffer 7.
03 and the buffer 5, and the write data is written to the specified register 4 via the write command signal 102 and the bidirectional data input/output buffer 8 via the external connection terminal 54. At the same time, via the write command signal 102,
The bidirectional address input/output buffer 6 outputs the written address information of the register 4 to the outside via the external connection terminal 53. Through this series of write operations, changes in the data contents in register 1 inside the microcomputer can be easily observed from the outside even when the microcomputer is continuously executing a real-time control program. becomes possible.

Further, in this second embodiment, the write signal 103 and the instruction execution stop signal 104 from the outside are output from the terminal 55 and the terminal 56, respectively.
By inputting the instruction execution stop signal 104 to the buffers 5 and 7 via the circuit 9 and inputting the instruction execution stop signal 104 to the buffers 5 and 7 from the terminal 56, the rewriting address for the register 4 is designated from the external connection terminal 53, and the terminal Data to be rewritten can be input from 54 and written into register 4.

[0015] In the above explanation, the operation was explained in the case of a register included in a microcomputer, but even if data memory is replaced in place of this register, the same operation will not be performed. , is the same as in the first embodiment.

[0016]

As explained above, the present invention provides an address buffer and a data buffer that output address information and write data in response to a write instruction to a register (or data memory) in a microcomputer. By providing this, it becomes possible to check the data contents of the register in real time even while the microcomputer is operating, and there is an effect that the efficiency of program development can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a portion of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a portion of a second embodiment of the invention.

FIG. 3 is a block diagram showing a part of a conventional example.

FIG. 4 is a block diagram showing parts of another conventional example.

[Explanation of symbols]

1, 4, 10, 12 Register 2, 3, 5 to 8, 11, 13 Buffer 9
AND circuit

Claims (1)

[Claims] 1. In a microcomputer having a register or data memory for microcomputer control, when writing data to the register or data memory via a predetermined write command signal, the register or data - Write data to the register or data memory via an address output buffer that outputs write address information corresponding to the memory to the outside of the microcomputer under the control of the write command signal, and the write command signal. when writing data information to the register or data memory under the control of the write command signal,
A microcomputer comprising: a data output buffer for outputting data to the outside of the microcomputer.