Browse Prior Art Database

MICRO Channel Common Communications Adapter

IP.com Disclosure Number: IPCOM000122128D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 149K

Publishing Venue

IBM

Related People

Fox, DB: AUTHOR [+3]

Abstract

Disclosed is a building block for high-speed MICRO CHANNEL* communications adapters. By adding the data link control and physical layers to this base design, virtually any kind of communications adapter may be built. These adapters can use the MICRO CHANNEL to transfer data to another adapter or to a MICRO CHANNEL host.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 47% of the total text.

MICRO Channel Common Communications Adapter

      Disclosed is a building block for high-speed MICRO
CHANNEL* communications adapters.  By adding the data link control
and physical layers to this base design, virtually any kind of
communications adapter may be built.  These adapters can use the
MICRO CHANNEL to transfer data to another adapter or to a MICRO
CHANNEL host.

      The MICRO CHANNEL provides a high-speed backbone with a defined
logical, electrical, and mechanical interface for transferring data.
The high bandwidth and bus master capabilities of the MICRO CHANNEL
make it an ideal bus for communications applications.  Network
routing equipment typically requires a backbone bus for transferring
data packets between different networks.  The MICRO CHANNEL provides
this capability in addition to allowing communications to a MICRO
CHANNEL host device, such as a RISC System/6000* workstation or a
PS/2* computer.  As a bus master on the MICRO CHANNEL, an adapter may
transfer data directly to another adapter or to system memory.  If
data is to be transferred directly from one adapter to another, the
adapter must be able to perform network layer functions.  If the
adapter is fetching data directly from system memory for an endpoint
host device, the adapter might be configured to perform functions up
to the transport layer.

      MICRO CHANNEL communications adapters using the common design
described in this article need only to provide the data link and
physical interface layers to make a complete networking adapter.
MICRO CHANNEL transfer and data control functions remain the same for
different adapters.  The intent of the MICRO CHANNEL common
communications adapter is to provide these common functions for a
variety of MICRO CHANNEL network adapters.

      The figure shows a block diagram of the common adapter
architecture.  The solid boxes are different pieces of the common
MICRO CHANNEL adapter design.  The dashed boxes represent components
which are added to personalize the adapter for a specific network
interface.

      The heart of the MICRO CHANNEL transfer function is the MICRO
CHANNEL Interface Controller (MIC).  The MIC transfers data packets
between the MICRO CHANNEL and the Local Data Storage (LDS) buffer.
The Intel 80960CA microprocessor controls where and when the data is
moved.  The microprocessor stores the command and pointer information
for the MIC in the Slow Local Processor Storage (Slow LPS). Certain
control and status information can also be passed directly between
the microprocessor and the MIC.

      The MIC has three large interface buses: the MICRO CHANNEL bus,
the LDS bus for transferring the data packets, and the Local
Processor Storage (LPS) bus for obtaining control information.
Because of the large number of I/O operations involved, additional
components have been added to provide some relief.  The LDS Memory
Management Unit (MMU) shown in the figure interfaces the MIC...