Browse Prior Art Database

Method Of Providing A Programmable Arbitration Level Per Memory Channel For Personal Computers

IP.com Disclosure Number: IPCOM000106329D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Boury, BF: AUTHOR [+4]

Abstract

Described is a software implementation for personal computers equipped with a Micro Channel* (MC) facility to have the ability to provide a programmable arbitration (ARB) level for each direct memory access (DMA) channel. This functional enhancement allows DMA channels to respond in a predictable manner to an individually programmed arbitration level.

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Method Of Providing A Programmable Arbitration Level Per Memory Channel For Personal Computers

      Described is a software implementation for personal computers
equipped with a Micro Channel* (MC) facility to have the ability to
provide a programmable arbitration (ARB) level for each direct memory
access (DMA) channel.  This functional enhancement allows DMA
channels to respond in a predictable manner to an individually
programmed arbitration level.

      Personal computers, equipped to support multiple DMA channels,
require that each of the DMA channels be programmed to any
arbitration level, except 'F'H which is reserved for the central
processing unit (CPU).  At reset time, the arbitration level is set
equal to the channel number, such as DMA channel 0 corresponds to ARB
level '0'H.  Since the MC arbitration levels also determines the
priority, this feature can be used to change the priority of the DMA
channel.

      The concept described herein provides the ability for a DMA
device to perform many different transfers to the same slave device
without requiring the intervention of the CPU.  It provides the
ability to program arbitration levels so that several DMA channels
can be programmed to the same arbitration level.  Circuitry which
enables the use of multiple DMA channels provides unique logic which
internally resolves which channel will respond to instructions.  When
two or more DMA channels are programmed to the same ARB level and the
channels...