JPS55138148A - Microprogram memory unit - Google Patents

Microprogram memory unit

Info

Publication number
JPS55138148A
JPS55138148A JP4465379A JP4465379A JPS55138148A JP S55138148 A JPS55138148 A JP S55138148A JP 4465379 A JP4465379 A JP 4465379A JP 4465379 A JP4465379 A JP 4465379A JP S55138148 A JPS55138148 A JP S55138148A
Authority
JP
Japan
Prior art keywords
memory
address
reducing
data
bus
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP4465379A
Other languages
Japanese (ja)
Inventor
Masao Watari
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP4465379A priority Critical patent/JPS55138148A/en
Publication of JPS55138148A publication Critical patent/JPS55138148A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE: To reduce memory elements in number without reducing a request program in the number of words and word length by limiting the use of functions of microprocessor to a certain address area.
CONSTITUTION: From address bus 5 to selecting circuit 1, an address is supplied and selecting circuit 1 judges whether the address is a value in a certain area. Then, either of memory part 2 stored with all field data and fixed-value output circuit 4 of memory part 3 stored with part of field data of data bits outside of the address area is selected. When memory part 2 is selected by selecting circuit 1, memory data are outut to memory data bus 6 and when output circuit 4 of memory part 3 is selected, fixed bit patterns are output from output circuit 4 to bus 6, thereby reducing the number of memory elements without reducing request programs in the number of words and word length.
COPYRIGHT: (C)1980,JPO&Japio
JP4465379A 1979-04-12 1979-04-12 Microprogram memory unit Pending JPS55138148A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4465379A JPS55138148A (en) 1979-04-12 1979-04-12 Microprogram memory unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4465379A JPS55138148A (en) 1979-04-12 1979-04-12 Microprogram memory unit

Publications (1)

Publication Number Publication Date
JPS55138148A true JPS55138148A (en) 1980-10-28

Family

ID=12697398

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4465379A Pending JPS55138148A (en) 1979-04-12 1979-04-12 Microprogram memory unit

Country Status (1)

Country Link
JP (1) JPS55138148A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07271411A (en) * 1995-03-31 1995-10-20 Omron Corp Fault diagnostic device for programmable controller

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07271411A (en) * 1995-03-31 1995-10-20 Omron Corp Fault diagnostic device for programmable controller

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