Browse Prior Art Database

Power Control Network for Multiple Towers in a Computer System

IP.com Disclosure Number: IPCOM000104673D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 116K

Publishing Venue

IBM

Related People

Agha, SA: AUTHOR [+4]

Abstract

A low-cost method of controlling power and providing diagnostic information between a base system unit and one or more expansion units is described.

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This is the abbreviated version, containing approximately 52% of the total text.

Power Control Network for

Multiple

Towers

in a Computer System

      A low-cost method of controlling power and providing diagnostic
information between a base system unit and one or more expansion
units is described.

      To introduce tower units, power control becomes critical among
base unit and tower units.  Without incorporating the logic into the
power supply and substantial cost increase, the functions are built
into the operator panel of the base unit and the control panel of the
tower unit microcode.  The communication is through the manufacturing
interface (MI).

      Through the MI, several commands are identified as
base-to-tower power control commands.  A hardware signal is used to
gate a programmable array logic (PAL) to control the destination of
the serial commands.  There are two recipients of the commands, MI
and tower units.  To MI, it will be the normal manufacturing testing
and debugging while to tower units, it will be power control
commands.  There are three commands identified for the tower units to
intercept:

     power on          : 05 00 00 0X
     power off         : 05 00 00 FX
     checksum retrieve : 05 00 00 50

      The sequence of numbers following the commands are the actual
hex digits that are transmitted through the serial port.  The
checksum retrieve command is devised for manufacturing testing of the
tower control panel microcode for verification of the ROS level.

      The "X" in the hex command designates the unit that sent out
the command.  For example, if it is the base unit that sent out the
command; its value will be "1".  The first tower unit that receives
this command will interpret the command and, if hardware indicates
that there are more tower units along the line, the first tower will
change that "1" into "2" and send it to the next unit.  In effect,
all tower units will be able to identify its position in the daisy
chain and the mechanism provides for more than one tower unit
attachment.

      For power status reporting, every tower unit after receiving
the power-on command serially should report a power status message to
the base unit in the form of:

      05 00 0X YZ where "X" is the tower unit address determined in
the command receiving sequence.  "YZ" byte is coded as:

Y : Battery Backup/UPS status
  Y1 : UPS on (MSB)
  Y2 : Utility Failure/Battery Active
  Y3 : UPS Bypass Active
  Y4 : Battery Low

Z : Power Supply Status
  Z1 : Expansion Battery Low
  Z2 : Power Supply Diagnostic Bit 2
  Z3 : Power Supply Diagnostic Bit 1
  Z4 : Power Supply Diagnostic Bit 0 (LSB)

For checksum reporting, the status message will be:

05 00 HH LL where "HH" is the high byte and "LL" is the low byte of
the tower contr...