公开(公告)号：NZ228610A

公开(公告)日：1991-03-26

申请号：NZ22861089

申请日：1989-04-04

Applicant: IBM

Inventor： BLAND PATRICK MAURICE ,  DEAN MARK EDWARD

IPC: G06F13/36 ,  G11C11/401 ,  G06F13/362 ,  G11C7/10 ,  G06F12/08

Abstract: A computer system includes a page memory in which a row address accompanied by a row address strobe (RAS) is followed by a column address accompanied by a column address strobe (CAS) to read data from a memory location during a memory cycle. When, in a following memory cycle, a further location from the same page is to be accessed, the row address and the RAS remain constant and a new column address is used with the CAS being precharged by switching it to its OFF state and then returning it to its ON state. This is normally done at the start of the following memory cycle. In the present system, the data is read and latched shortly after arrival of the column address and CAS in the first of the memory cycles so that the CAS recharge can take place at the end of the first memory cycle and before the start of the following memory cycle.

公开(公告)号：GB2219110B

公开(公告)日：1991-02-20

申请号：GB8912018

申请日：1989-05-25

Applicant: IBM

Inventor： BEGUN RALPH MURRAY ,  BLAND PATRICK MAURICE ,  DEAN MARK EDWARD

IPC: G06F9/38 ,  G06F12/08

Abstract: In a microcomputer system comprising a microprocessor and a cache subsystem and operable in a pipelined mode, there is potential incompatibility between pipelined operations and dynamic bus sizing as the cache subsystem operates with a fixed size data width and dynamic bus sizing allows the system to operate with devices of differing data width. This incompatibility is accommodated by the present system by defining certain addresses as cacheable addresses and other addresses as non-cacheable addresses and ensuring that addresses of devices of data width different from the cache data width are non-cacheable. An address decoder provides a control signal indicating whether or not a generated address is within the cacheable range. This control signal controls a next address signal applied to the microprocessor, which signal allows the processor to proceed to a following cycle prior to the end of the current cycle. Whenever a non-cacheable address is detected, the next address signal is suppressed.

公开(公告)号：HK81590A

公开(公告)日：1990-10-19

申请号：HK81590

申请日：1990-10-11

Applicant: IBM

Inventor： DEAN MARK EDWARD ,  MOELLER DENNIS LEE

IPC: G06F9/46 ,  G06F9/38 ,  G06F11/00 ,  G06F11/07 ,  G06F13/36 ,  G06F15/16 ,  G06F15/177

Abstract: In a data processing system including a main processor (1) and a co-processor (2), a logic circuit (6) is coupled to receive error and busy outputs of the co-processor to generate an interrupt output on co-incidence of active error and busy signals and to latch the busy signal to the main processor to ensure that the main processor will honour the interrupt before executing another co-processor instruction.

公开(公告)号：PH24588A

公开(公告)日：1990-08-17

申请号：PH31371

申请日：1984-10-26

Applicant: IBM

Inventor： DEAN MARK EDWARD ,  MOELLER DENNIS LEE

IPC: G06F13/28 ,  G06F9/00

Abstract: A microcomputer system includes a main processor (1), a memory (3) and a direct memory access controller (DMA;4) effective to control direct data transfer between the memory and input / output devices on channels. Bus control for data transfer is switchable between the DMA and processor by a hold request/acknowledge handshaking sequence between the DMA and processor. A control line (27) from the channels is activated by a peripheral processing device on a channel when it wishes to gain control of the busses for data transfer. Logic means co-act with the handshaking sequence to determine which device gains control of the busses. This logic is responsive to the DMA address enable output (AEN), the hold acknowledge output of the main processor (HLDA) and the channel control line output (-MASTER). When all these are deactivated, control passes to the main processor, when AEN and HLDA only are activated, control passes to the DMA controller and, when all three are activated, control passes to the peripheral processing device.

公开(公告)号：HK4290A

公开(公告)日：1990-01-25

申请号：HK4290

申请日：1990-01-18

Applicant: IBM

Inventor： SAENZ JESUS ANDRES ,  DEAN MARK EDWARD ,  KUMMER DAVID ALLEN

IPC: G09G5/02 ,  G09G1/28

公开(公告)号：PH23949A

公开(公告)日：1990-01-23

申请号：PH31332

申请日：1984-10-12

Applicant: IBM

Inventor： DEAN MARK EDWARD

IPC: G11C11/24 ,  G06F12/00 ,  G11C11/406 ,  G11C7/02

Abstract: A refresh generator system (5) for a dynamic memory (3) in a data processing system, including a processor (1) which is responsive to a hold request signal (HRQ) to relinquish control of the local bus and generate a hold acknowledge signal (HLDA), comprises logic means (14,11.10,13) to generate a hold request signal in response to an output from a refresh timer circuit (6). A logic circuit (16) is responsive to a hold request, a corresponding hold acknowledge, and the timer signal to generate a refresh control signal (REFR). This signal generates a refresh signal for the memory control circuits, increments a counter circuit (19) and initiates operation of a sequencer circuit (22). The sequencer then gates the output of the counter circuit to provide a memory row address and thereafter provides a memory read output (-MEMR) to refresh the memory row defined by the address and lastly resets the circuit to terminate the hold request signal.

公开(公告)号：BR8902393A

公开(公告)日：1990-01-16

申请号：BR8902393

申请日：1989-05-24

Applicant: IBM

Inventor： BEGUN RALPH MURRAY ,  BLAND PATRICK MAURICE ,  DEAN MARK EDWARD

IPC: G06F9/38 ,  G06F12/08 ,  G06F9/00

Abstract: In a microcomputer system comprising a microprocessor and a cache subsystem and operable in a pipelined mode, there is potential incompatibility between pipelined operations and dynamic bus sizing as the cache subsystem operates with a fixed size data width and dynamic bus sizing allows the system to operate with devices of differing data width. This incompatibility is accommodated by the present system by defining certain addresses as cacheable addresses and other addresses as non-cacheable addresses and ensuring that addresses of devices of data width different from the cache data width are non-cacheable. An address decoder provides a control signal indicating whether or not a generated address is within the cacheable range. This control signal controls a next address signal applied to the microprocessor, which signal allows the processor to proceed to a following cycle prior to the end of the current cycle. Whenever a non-cacheable address is detected, the next address signal is suppressed.

公开(公告)号：HK102489A

公开(公告)日：1990-01-05

申请号：HK102489

申请日：1989-12-28

Applicant: IBM

Inventor： DEAN MARK EDWARD

IPC: G11C11/24 ,  G06F12/00 ,  G11C11/406

Abstract: A refresh generator system (5) for a dynamic memory (3) in a data processing system, including a processor (1) which is responsive to a hold request signal (HRQ) to relinquish control of the local bus and generate a hold acknowledge signal (HLDA), comprises logic means (14,11.10,13) to generate a hold request signal in response to an output from a refresh timer circuit (6). A logic circuit (16) is responsive to a hold request, a corresponding hold acknowledge, and the timer signal to generate a refresh control signal (REFR). This signal generates a refresh signal for the memory control circuits, increments a counter circuit (19) and initiates operation of a sequencer circuit (22). The sequencer then gates the output of the counter circuit to provide a memory row address and thereafter provides a memory read output (-MEMR) to refresh the memory row defined by the address and lastly resets the circuit to terminate the hold request signal.

公开(公告)号：GB2219418A

公开(公告)日：1989-12-06

申请号：GB8904917

申请日：1989-03-03

Applicant: IBM

Inventor： BLAND PATRICK MAURICE ,  DEAN MARK EDWARD

IPC: G11C11/401 ,  G06F13/36 ,  G06F13/362 ,  G11C7/10

Abstract: A computer system includes a page memory in which a row address accompanied by a row address strobe (RAS) is followed by a column address accompanied by a column address strobe (CAS) to read data from a memory location during a memory cycle. When, in a following memory cycle, a further location from the same page is to be accessed, the row address and the RAS remain constant and a new column address is used with the CAS being precharged by switching it to its OFF state and then returning it to its ON state. This is normally done at the start of the following memory cycle. In the present system, the data is read and latched shortly after arrival of the column address and CAS in the first of the memory cycles so that the CAS recharge can take place at the end of the first memory cycle and before the start of the following memory cycle.

公开(公告)号：FR2632096A1

公开(公告)日：1989-12-01

申请号：FR8905077

申请日：1989-04-11

Applicant: IBM

Inventor： BLAND PATRICK MAURICE ,  DEAN MARK EDWARD ,  MILLING PHILIP ERNA

IPC: G06F9/44 ,  G06F9/445 ,  G06F13/36 ,  G06F13/362

Abstract: A multi-bus microcomputer system includes a cache subsystem and an arbitration supervisor. A CPU is provided with a PREEMPT signal source which generates a preempt signal in CPU cycles extending beyond a specified duration. The preempt signal is effective at any device having access to the bus to initiate an orderly termination of the bus usage. When that device signals its termination of bus usage, the arbitration supervisor changes the state of an ARB/GRANT conductor, which had been in the grant phase, to the arbitration phase. During the arbitration phase each of the devices (other than the CPU) cooperates in an arbitration mechanism for bus usage during the next grant phase. On the other hand, the CPU, having asserted preempt, responds to a signal indicating initiation of the arbitration phase by immediately accessing the system bus.