公开(公告)号：MY104505A

公开(公告)日：1994-04-30

申请号：MYPI19901890

申请日：1990-10-29

Applicant: IBM

Inventor： ROBERT DEAN YODER ,  SERAFIN JOSE ELEAZAR GARCIA JR ,  RUSSEL STEPHEN PADGETT ,  DOUGLAS RODERICK CHISHOLM ,  DEAN ALAN KALMAN

IPC: G06F13/32 ,  G06F13/362

Abstract: A PLURALITY OF SPECIALIZED CONTROLLERS (E.G., 202, 204& 206), EACH ONE ADAPTED TO CONTROL A PARTICULAR TYPE OF DATA TRANSFER OPERATION, CONTROL THE FLOW OF DATA BETWEEN A SYSTEM BUS (104) AND A LOCAL BUS (106) ON A COMPUTER ADAPTER CARD (102). WHEN THE DIRECT MEMORY ACCESS (DMA) CONTROLLER (202) IS CONTROLLING A DMA OPERATION ON THE LOCAL BUS, CERTAIN OTHER CONTROLLERS (204 & 206) CAN BREAK-IN TO THE CURRENT DMA OPERATION, TEMPORARILY HALTING THE DMA OPERATION UNTIL THE OTHER CONTROLLER HAS COMPLETED ITS DATA TRANSFER OPERATION.TO BREAK IN TO A DMA OPERATION, HANDSHAKING SIGNALS THE DMA CONTROLLER AND THE LOCAL BUS INTERFACE CIRCUIT (212) ARE TEMPORARILY BLOCKED BY BLOCKING SIGNALS FROM A BREAK-IN LOGIC CIRCUIT (210). THE BREAK-IN CIRCUIT INCLUDES A FOUR-STATE MACHINE TO BLOCK THE HANDSHAKING SIGNALS AT THE APPROPRIATE TIMES, AND TO SIGNAL THE INTERRUPTING CONTROLLER TO BEGIN ITS DATA TRANSFER OPERATION. WHEN BREAKING-IN TO A DMA OPERATION IN THIS MANNER, THE OPERATION OF THE DMA CONTROLLER IS NOT ALTERED, INSTEAD, TO THE DMA CONTROLLER, IT APPEARS THAT THE LOCAL BUS INTERFACE CIRCUIT IS MERELY SLOW TO RESPOND WITH ITS ACKNOWLEDGE HANDSHAKE.(FIG. 2)

公开(公告)号：IN179860B

公开(公告)日：1997-12-27

申请号：IN903MA1994

申请日：1994-09-15

Applicant: IBM

Inventor： PADGETT RUSSELL STEPHEN ,  CHISHOLM DOUGLAS RODERICK ,  SERAFIN JOSE ELEAZAR GARCIA JR ,  ALVAREZ RAFAEL ,  KALMAN DEAN ALAN ,  YODER ROBERT DEAN

IPC: G06F3/00 ,  G06F12/06