JPS63129414A - Memory mapped external storage system for microcomputer - Google Patents

Abstract

PURPOSE:To shorten an access time, by providing a connector connected directly to an address bus, a data bus, and another control line, an external memory unit connected to the connector, and a ROM which stores a procedure to memory-map the external memory unit, at a control part. CONSTITUTION:When a power source is applied, a system program stored in the ROM10 in the control part 9 is executed by a central processing part 11. After initialization for every part being completed, the control part 9 performs a processing for the command of an input/output part 13. And a processed data is written on or read out from a memory cell E<2>PROM (non- volatile read/write memory) 2 in the external memory unit 1 via the connector 16 after being memory-mapped from the address bus 3' and the data bus 4' at need. After a processing is completed, the external memory unit 1 is removed from the connector 16, and is preserved, and when necessary, the external memory unit 1 is connected to the connector 16, thereby, the data written on the E<2>PROM2 can be updated.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a storage system for a microcomputer system, and more particularly to a small-scale external storage system.

BACKGROUND OF THE INVENTION Conventionally, external storage systems for microcomputers of this type include a control unit having at least a central processing unit, an address and data bus, memory ROM and RAM, an interface for accessing external storage, and a decoder. and an external storage device connected to this interface, and this external storage device used a floppy disk, magnetic tape, magnetic disk, magnetic drum, etc. Therefore, these external storage devices are large and expensive, and are unsuitable when only a small storage capacity is required.

Furthermore, this conventional method has the disadvantage that it takes time to access the memory because an interface is used for inputting and outputting data.

Problems to be Solved by the Invention The purpose of the present invention is to solve the above-mentioned drawbacks, namely, that external storage devices are large and expensive, and access time is long due to the use of an interface. The object of the present invention is to provide an external storage method that solves the problem that it is unsuitable.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides at least a central processing unit, an address and data bus, a memory ROM for storing procedures for storage, etc., and a work area. A control unit that has a memory RAM used for such applications, a decoder, an address bus, a data bus, and a connector that is directly connected to control lines such as memory write, memory read, and chip select, and a small-capacity nonvolatile external device that is connected to this connector. A storage unit is provided, and a memo 980M stores a procedure for memory mapping this external storage unit.

Operation Since the present invention is configured as described above, the data processed within the control section can be memory mapped to an external storage unit and can be written and read as necessary. Also, use this external storage unit as F; EPB, OM.
Alternatively, by making it non-volatile as RAM backed up by a power supply, it can be removed and stored.

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

Referring to FIG. 1, which shows a first embodiment of the present invention in the form of a block diagram, the microcomputer of the present invention has an external storage unit 1, a control section 9, an input/output section 13, and an external The storage unit includes an E2PROM (nonvolatile read/write memory) 2 as a storage element, an address bus 3, a data bus 4, a chip select line 5, and a memory lead line 6.
, a memory write line 7, and a printed wiring board 8 on which these are arranged. The control unit 9 also connects the external storage unit 1 with a ROM10 storing software for reading and writing data, R and AM12 used as work areas, an interface 14 for the input/output unit 13, and an external A decoder 15 for memory mapping the storage unit 1 and a central processing unit 11 for controlling these systems! : directly connected to address bus 3' and data bus 4', chip select line 5' from decoder 15, memory read line 6' and memory write line 7' from central processing unit 11, and these buses and control lines. An external storage unit l is connected to the connector 16. Further, the input/output section 13 is connected to the input/output section interface 14 of the control section 9 .

Next, the operation of this embodiment will be explained using FIG.

First, when the power is turned on, the central processing unit 11 executes the system program stored in 1 (,0Ml0) of the control unit 9. After the initial settings of each unit are completed, the control unit 9
performs processing on commands from the input/output unit 13. This processed data is then transferred to the address bus 3 as necessary.
' and the data bus 4' to the memory element E''F of the external storage unit 1 via the connector 16.
It is written to and read from ROM2. When the processing is completed, the external storage unit 1 is removed from the connector 16 and stored, and if necessary, the external storage unit 1 is connected to the connector 16 and the data written in the E''FROM 2 is updated.

Note that the storage capacity of E2FROM2 is the same as that of central processing unit 1.
Depending on the capacity of 1, for example, the 8085, which has 16 general address buses, can have several tens of kilobytes.

FIG. 2 shows a second embodiment of the present invention, in which an AM17 and a backup power supply 18 are used in place of the memory element E"PROM2 in FIG. 1, and its operation is the same as in the first embodiment. It is explained exactly like the example.

Effects of the Invention As explained above, according to the present invention, a control unit includes a connector directly connected to an address bus, a data bus, and other control lines, an external storage unit connected to this connector, and an external storage unit. By providing a ROM for storing memory mapping procedures, it is possible to obtain a compact and inexpensive external storage system with short access time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of the invention, and FIG. 2 is a block diagram of an external storage unit of the second embodiment of the invention. l...External storage unit, 2...EE
PROM (memory element), 3.3'・°'...address bus, 4,4'...data bus, 5,5'...
....Chip-by-chip power line, 6.6'...Memory lead wire, 7,7'...°...Memory write line, 8
・・・・・・Printed wiring board, 9・・・・・・Control unit,
10...ROM111...Central processing unit, 12...RAM, 13...-Person output unit,
14... Input/output controller, 15...
・Decoder, 16... Connector, 17...
・RAM118...- Backup power supply. Chrysanthemum / times 77 /”w4M /8 ノ)゛Tsukufu゛Electric broadcasting mouse Z diagram

Claims (1)

[Claims] At least a central processing unit, an address and data bus, a memory ROM for storing procedures for storage, etc.
, a memory RAM used as a work area, an interface for accessing external storage, a decoder, a chip select line from the decoder, and control lines such as a memory read line and a memory write line from the central processing unit. In an external storage system for a microcomputer comprising a control unit having a controller and an external storage device connected to the interface, the external storage device connected to the interface is removed and the address bus is
A procedure for providing a connector directly connected to a data bus and control lines such as memory write, memory read, and chip select, and a small-capacity nonvolatile external storage unit connected to this connector, and memory mapping the external storage unit to the ROM. 1. A memory mapped external storage system for a microcomputer, characterized in that the external storage unit is memory mapped and stored by storing .