JPS585843A - Optional address starting device - Google Patents

Abstract

PURPOSE:To simplify control logic and a control circuit by utilizing the instruction system of a microprocessor part. CONSTITUTION:A starting address is set up on a switch information part 4. When a reset signal is inputted from a signal input line 7, 4 bits of the MSB side of a data sent from storage circuit part 2 to a microprocessor part 1 through a data bus 5 are masked and the 4 bits are forcedly turned to logic ''0''. A data coincidence detection circuit part 9 compares an address value from the switch information part 4 with that on an address bus 8 and, when both the values coincide each other, outputs a signal to a data bus through a control circuit part 30 to unmask the upper MSB4 bits of the data on the data bus 5, so that the microprocessor 1 starts normal operation at the time of unmasking.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides a start address (s) of a microprocessor.
tart address) control device.

In emergency equipment that uses a microprocessor, it is necessary to run a program on one microprocessor from an arbitrary address point when adjusting the equipment. A conventional device for performing such an operation is shown in FIG. In the figure, (1) is a microprocessor section, (2) is a storage circuit section, (3) is a control circuit section, (4) is a switch information section, (5) is a data bus, (6) is a control bus, (7) is a reset signal input line.

Next, the operation will be explained. A numerical value indicating the start address of the microprocessor is set in the switch information field (4). Signal power 1! When the reset signal from (7) is input to the microprocessor unit (1) K, the microprocessor unit (1) turns off the data bus (5) between the memory circuit unit (2) and the microprocessor unit (1), and turns the control circuit The data bus from the section (3) to the microprocessor section (1) is turned on. 2, from the control circuit section (3), an instruction containing the unconditional jump instruction code used in the microprocessor section (1) and the rounding switch information section (4) K that indicates the jump destination address. to the microprocessor section (1) via the bus (5)
When this is completed, the data bus (5) between the memory circuit section (2) and the microprocessor section (1) is turned on.
The data bus (5) between the control circuit section (3) and the microprocessor section (1) is turned off.

Through the above operations, the microprocessor starts operating from the address set in the switch information section (4)K.

Since the conventional device is configured as described above, the unconditional skip instruction code used in the microprocessor section (1) must be set in the control circuit section (3), and the control circuit section ( There were drawbacks such as the logic of 3) being complex.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it simplifies the control logic by using the instruction system of the microprocessor section (!). The purpose of this invention is to provide a start address control device that simplifies the process.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing one embodiment of the present invention.
The same reference numerals as in the figure indicate the same parts, (8) is an address bus, (9) is a data coincidence detection circuit section, and (to) is a control circuit section of the present invention.

Next, the operation of the circuit shown in FIG. 2 will be explained. Setting the start address in the switch information section (4) is the same as in the case of FIG. When a reset signal is input from the signal input line (7), the data bus (5) is input from the memory circuit section (2).
), the microprocessor section (1) masks the 4 bits on the M8B side of the data flowing through the K (by using a gate to block their passage) and forces those 4 bits into logic.
Make it O.J. In this way, the memory circuit section (
This means that the branch instruction (jump instruction) among the instructions read from 2) has been deleted. Even in microprocessors of other types than those mentioned above, it is easy to perform table control to erase branch instructions among instructions read from the storage circuit section (2) by means corresponding to the instruction system. In this way, the numerical value of the address outputted from the microprocessor section (1) to the address bus (8) becomes K as it increases sequentially from 1 to 1.

The data match detection circuit section (9) compares the address value from the switch information section (4) with the address value on the address bus (8), and if the two match, the control path (6)
The microprocessor unit (1) outputs a signal to unmask the upper M8B4 bits of data on the data bus (5) via the control circuit unit (to), and from this point on, the microprocessor unit (1) starts normal operation.

In the embodiment shown in FIG. 2, the switch information section (4) and the data match detection circuit section (9) are provided as hardware, but in some cases, the selection signal of the storage circuit section (2) may be used. Therefore, the switch information section (4) and the data coincidence detection circuit section (9) can be omitted, further simplifying the hardware.

As described above, according to the present invention, the arbitrary address start device can be simplified in hardware by using the instruction system of the microprocessor itself, so the device can be made inexpensive, and It becomes easy to attach and detach the address start device to the system.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional device, and FIG. 2 is a block diagram showing an embodiment of the present invention. (1)...Microprocessor section, (2)...Storage circuit section, (to)...Control circuit section, (4)...Switch information section, (5)...Data bus, ( 7)...Reset signal input line, (8)...Address bus, (9)...
...Data match detection circuit section. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Makoto Kuzuno - Procedural amendment (voluntary) Commissioner of the Japan Patent Office 1, case description Patent application 1986-1040584#
2. Name of the invention Address start device 3. Person making the amendment 5. Detailed description of the invention in the specification to be amended 6. Contents of the amendment (1) Page 5, lines 6 to 6 of the specification At the beginning of line 7, correct the phrase ``1 address'' to ``1 each''. (2) In the 3rd line of page 6 of the same book, the phrase ``system wo'' is corrected to ``system wo''. (or more) (,ri

Claims (1)

[Scope of Claims] A microprocessor unit and a memory circuit unit that stores instructions for instructing the operation of the microprocessor unit, and is controlled to start execution from an instruction at an arbitrary address position in the memory circuit unit. In an arbitrary address start device that commands a start, a part of a field containing an instruction code for instructing a jump in an instruction word read from the memory circuit section and inputted to the microprocessor section by a reset signal for instructing a start; and means for detecting a point in time when an address value given from the microprocessor section to the memory circuit section matches a desired address value, and canceling the mask at this point. Any address start device.