JPS54127235A - Direct memory access unit - Google Patents

Direct memory access unit

Info

Publication number
JPS54127235A
JPS54127235A JP3423278A JP3423278A JPS54127235A JP S54127235 A JPS54127235 A JP S54127235A JP 3423278 A JP3423278 A JP 3423278A JP 3423278 A JP3423278 A JP 3423278A JP S54127235 A JPS54127235 A JP S54127235A
Authority
JP
Japan
Prior art keywords
mem13
mpu12
memory access
direct memory
instruction
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
JP3423278A
Other languages
Japanese (ja)
Inventor
Kenji Shoroji
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.)
Toshiba Corp
Original Assignee
Toshiba Corp
Tokyo Shibaura 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 Toshiba Corp, Tokyo Shibaura Electric Co Ltd filed Critical Toshiba Corp
Priority to JP3423278A priority Critical patent/JPS54127235A/en
Publication of JPS54127235A publication Critical patent/JPS54127235A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE: To obtain a direct memory access unit which exercises DMA control by transferring data with a memory circuit (MEM) while a MPU is an instruction decoding cycle, without lowering the arithmetic speed of a central arithmetic processor (MPU) with its operation interrupted even if a direct memory access (DMA) request arrives from an I/O.
CONSTITUTION: On receiving a clock from crystal oscillator 11, MPU12 outputs a signal which indicates the state it should do itself and also outputs simultaneously an address from MPUBUF13 to MEM13 via MPUBUS121. By way of DTBUS132 and data-bus changeover circuit 17, data selected from MEM13 are inputted to MPU12, which starts the decoding of an instruction. Once MPU12 fetches the instruction, the address becomes unneeded. If I/O14 requires a DMA function while sending out DMA142 signal, I/O14 and MEM13 are coupled together, so that data transfer will become possible.
COPYRIGHT: (C)1979,JPO&Japio
JP3423278A 1978-03-27 1978-03-27 Direct memory access unit Pending JPS54127235A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3423278A JPS54127235A (en) 1978-03-27 1978-03-27 Direct memory access unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3423278A JPS54127235A (en) 1978-03-27 1978-03-27 Direct memory access unit

Publications (1)

Publication Number Publication Date
JPS54127235A true JPS54127235A (en) 1979-10-03

Family

ID=12408393

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3423278A Pending JPS54127235A (en) 1978-03-27 1978-03-27 Direct memory access unit

Country Status (1)

Country Link
JP (1) JPS54127235A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5621223A (en) * 1979-07-30 1981-02-27 Ibm Cycle steal mechanism
JPS58144959A (en) * 1982-02-23 1983-08-29 Sony Corp Controller
JPS59165140A (en) * 1983-03-10 1984-09-18 Fujitsu Ltd Two-dimensional arithmetic circuit
JP2007239940A (en) * 2006-03-10 2007-09-20 Enomoto Co Ltd Check valve and check valve extended part

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5621223A (en) * 1979-07-30 1981-02-27 Ibm Cycle steal mechanism
JPS5820061B2 (en) * 1979-07-30 1983-04-21 インタ−ナショナル ビジネス マシ−ンズ コ−ポレ−ション cycle steel mechanism
JPS58144959A (en) * 1982-02-23 1983-08-29 Sony Corp Controller
JPS59165140A (en) * 1983-03-10 1984-09-18 Fujitsu Ltd Two-dimensional arithmetic circuit
JPH04300B2 (en) * 1983-03-10 1992-01-07 Fujitsu Ltd
JP2007239940A (en) * 2006-03-10 2007-09-20 Enomoto Co Ltd Check valve and check valve extended part

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