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Browse Prior Art Database

Micro Channel Streaming Data Burst Protocol for DMA Slaves

IP.com Disclosure Number: IPCOM000120212D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Arimilli, RK: AUTHOR [+4]

Abstract

Disclosed is a means by which DMA Slaves on the Micro Channel* are allowed to burst across disjointed Streaming Data packets. This provides an efficient and consistent means by which DMA Slaves can be given Streaming Data performance and flexibility similar to DMA Masters.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 99% of the total text.

Micro Channel Streaming Data Burst Protocol for DMA Slaves

      Disclosed is a means by which DMA Slaves on the Micro
Channel* are allowed to burst across disjointed Streaming Data
packets.  This provides an efficient and consistent means by which
DMA Slaves can be given Streaming Data performance and flexibility
similar to DMA Masters.

      The Micro Channel Architecture contains an open collector
signal, called -BURST, which allows DMA Slaves and Masters to
continue data transfers on the Micro Channel without having to
rearbitrate for the bus.  During Streaming Data transfers, the
Streaming control signals are driven inactive within a single
Streaming cycle.  Due to the open collector nature of -BURST,
however, a DMA slave cannot drive it inactive within a single
Streaming cycle.  Thus, Streaming Data performance is severely
degraded if DMA Slaves cannot drive the -BURST signal valid within a
single Streaming cycle.

      The figure contains a new burst protocol which allows DMA
Slaves to drive -BURST valid within a single Streaming cycle.  This
is achieved by having the DMA Slaves release -BURST with the first
-SD STROBE falling and during each Streaming cycle, -BURST is then
either driven low or left high.  Note that -BURST is never driven
inactive during the Streaming cycles.  This protocol supports all
combinations of DMA Controllers and DMA Slaves and provides full
compatibility with the existing Micro Channel Architecture.
*  Trademark of IBM...