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Controlling Host Personal Computer by Chipcard

IP.com Disclosure Number: IPCOM000118165D
Original Publication Date: 1996-Oct-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Nishino, K: AUTHOR [+3]

Abstract

ChipCard is a device in the form factor of a Personal Computer (PC) card, which functions as a very small computer when it stands alone, and functions as a slave PC card when it is inserted into a host PC to interface with. This article describes a method for ChipCard to control its host PC, which is in sleep state.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 67% of the total text.

Controlling Host Personal Computer by Chipcard

      ChipCard is a device in the form factor of a Personal Computer
(PC) card, which functions as a very small computer when it stands
alone, and functions as a slave PC card when it is inserted into a
host PC to interface with.  This article describes a method for
ChipCard to control its host PC, which is in sleep state.

      Most notebook PCs have a sleep function to save their battery
life.  The way to wake up from the sleep state by itself is very
limited except by the user's manual operation.  The -STSCHG signal of
the PC card slot can be used to wake up a PC.  Since ChipCard is
programmable, the way to wake up a PC will be programmable and
expanded very much.

      To implement this method, ChipCard should control -STSCHG
signal even when ChipCard is not functioning as a slave PC card.
ChipCard can be left in the PC card slot regardless of the PC's
power on/off/sleep status.  A problem when doing this is that the
power from the PC card slot, which is used for Input/Output (I/O)
cell's power,  may be turned off, while the source of the signal is
active.  This causes leakage current.  ChipCard is powered by its own
small battery,  and such leakage current is critical for its battery
life. Furthermore,  some PC's PC card slot signals are connected to
ground level when the slot's power is turned off.  In such case, the
problem becomes worse.

      This method employs specially designed gate arr...