JPS54127235A - Direct memory access unit - Google Patents
Direct memory access unitInfo
- 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
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
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)
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 |
-
1978
- 1978-03-27 JP JP3423278A patent/JPS54127235A/en active Pending
Cited By (6)
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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