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Browse Prior Art Database

Arbitration Level Program for Personal Computers

IP.com Disclosure Number: IPCOM000104598D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Klim, PJ: AUTHOR [+4]

Abstract

Described is a software implementation that provides arbitration level support for serial ports after completing the set-up during the power-on system test (POST) in personal computers (PCs). The concept enables the arbitration levels to be changed at any time by the software.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Arbitration Level Program for Personal Computers

      Described is a software implementation that provides
arbitration level support for serial ports after completing the
set-up during the power-on system test (POST) in personal computers
(PCs).  The concept enables the arbitration levels to be changed at
any time by the software.

      In prior art, the arbitration level for each programmable
communication (COM) port of a serial port could only be programmed
while in set-up mode during POST.  The concept described herein
provides a means whereby it is possible to program the arbitration
level without first placing the circuit chip into setup mode.  This
enables the arbitration levels to be programmed at any time.

      Typically, the PC will contain two serial ports and four local
arbiters.  Each serial port has its own independent transmit and
receive arbiters.  The arbitration levels for each arbiter are
programmable.  During POS setup time, each serial port (A and B) are
assigned a different COM port out of the sixteen COM ports available.
Direct memory access (DMA) mode in either of the serial ports may be
enabled in conjunction with the corresponding DMA channels.
Therefore, the arbitration levels must be assigned by software.  In
the prior art designs, the first serial port's arbitration level was
programmed first, setting port 94 bit 7 to zero and then writing the
transmit and receive arbitration level into port 104.  The second
serial port arbitration level was programmed by way of setup POS port
96.  In the concept's implementation, the arbitration levels for both
ports may be assigned independentl...