Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM AND METHOD FOR DETECTION OF AN ACCESSORY
DEVICE CONNECTED TO A PORTABLE COMPUTER
BACKGROUND OF THE INVENTION
Field of the Invention
This invention pertains to a portable computing device. More
specifically, embodiments of this invention provide for detecting and/or
determining a type of an accessory device connected to a portable computing
device.
Description of the Related Art
Portable computers such as laptop and handheld computers may be
provided with additional capabilities through the use of accessory devices.
The
accessory devices may electrically couple to a processor of the portable
computer to provide communication capabilities and external power: Accessory
devices in general have been used to add functions and resources to portable
computers to compensate for inherent limitations arising from their size and
mobility. Previous accessory devices have been used to provide, among other
things, an alternating current (A/C) supply, serial and parallel ports,
modems,
additional memory, and universal serial ports. The portable computer may use
accessory devices to communicate with larger computers and data networks.
Portable computers are typically equipped with a time-out feature that
turns the computer off after a predetermined duration of inactivity. The time-
out feature is designed to preserve battery life. While the time-out feature
may
be necessary when the portable computer is operating from an internal battery
source, accessory devices may supply an A/C converter to the portable
computer to eliminate the need for the time-out feature. However, previous
portable computers provide for the time-out feature to be enabled so that the
portable computer switches off after a period of inactivity, even if the
accessory
device is supplying external power. Still, other portable computers, such as
ZaurusTM personal digital assistant manufactured by the Sharp Corp. and
PalinPilotTM organizers manufactured by the 3Com Corp., disable the time-out
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feature only when an A/C power adapter is supplied to a power terminal of the
portable computer.
These devices do not disable the time-out feature when an accessory
device such as a communication cradle is connected to the portable computer
through a communications port. In such instances, the time-out feature can be
limiting and a nuisance to the user by precluding, for example, use of
programs
that require minimal user interaction. Therefore, there is a need for enabling
the
portable computer to detect whether an accessory device supplying external
power is actively connected to the portable computer.
Furthermore, a number of different types of accessories are available for
use with portable computers. However, previous portable computers are not
equipped to automatically determine the type of accessory device that is
actively connected to the portable computer. Without this ability, the user is
required to perform additional software functions to identify the particular
accessory device for the portable computer. In addition, the portable computer
may accidentally execute an application for an accessory device other than the
one being used. In certain applications, this can be harmful to the portable
computer and/or the accessory device. For example, the PalmPilot IIITM may
access a modem accessory device by executing a software application
configured only for modem devices. In some instances, the software
application may be damaging if the accessory device connected to the portable
computer is erroneously identified as a modem device. Therefore, there is a
need for enabling the portable computer to automatically determine the type of
the accessory actively connected to it.
These and other shortcomings of previous portable computers will be
addressed by various embodiments of this invention.
SUMMARY OF THE INVENTION
Embodiments of this invention provide for detecting a type of an
accessory device connected to a portable computer. The portable computer may
detect a signal from the accessory device and determine the type of accessory
device using the signal. Once the type of accessory is identified, the
portable
computer may implement a software that matches the particular type of
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accessory. The type of accessory may be identified by measuring a voltage of a
signal line that is coupled to the accessory device. The value of the voltage
on
the signal line may then be matched to a corresponding accessory type using a
memory of the portable computer. Examples of accessories for use with
embodiments of this invention include a modem device, a serial communication
cradle, and a Universal Serial Bus (USB) cradle.
An embodiment of this invention uses only a single line in a
communications or am output port to detect any one of multiple types of
accessory devices. This provides a simple and effective way to differentiate
between accessory devices that are coupled to the portable computing device.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 illustrates a portable computing device that may incorporate an
embodiment of the invention.
FIG. 2 is a schematic of an embodiment of this invention for detecting
an accessory device actively connected to a portable computing device.
FIG. 3 is an embodiment of this invention for detecting a type of an
accessory device connected to the portable computing device.
FIG. 4A is another embodiment of this invention for detecting a type of
an accessory device connected to the portable computing device.
FIG. 4B is another embodiment of this invention for detecting a type of
an accessory device connected to the portable computing device.
FIG. 5 is a flowchart of an algorithm for detecting a communication
device actively connected to the portable computing device.
FIG. 6 is a flowchart of another algorithm for determining a type of an
accessory connected to the portable computing device.
DETAILED DESCRIPTION
An embodiment of this invention provide for detecting a type of
accessory device connected to a portable computer. The portable computer then
implements software to accommodate the specific accessory device detected.
Another embodiment of this invention provides for detecting whether a
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communication accessory, such as a communication cradle, is actively
connected to the portable computer. The portable computer then suspends a
time-out feature, as the communication device supplies external power to the
portable computer.
S This disclosure initially describes a portable computer and accessory
device for use with various embodiments of the invention, including user
features of the portable computer that may be affected or altered. In FIG. 2
and
accompanying text, the disclosure describes hardware for detecting whether an
accessory device is connected to the portable computer. In FIGS. 3, 4A, and 4B
and text accompanying these figures, the disclosure describes embodiments for
detecting the type of accessory device connected to the portable computer. In
FIG. 5 and accompanying text, an algorithm is presented for detecting whether
the accessory device is actively connected to the portable computer. In FIG. 6
and accompanying text, an algorithm is described for detecting an accessory
type connected to the portable computer.
In an embodiment of this invention, the portable computer includes three
modes of operation. For purpose of this disclosure, an "on-mode" is a mode in
which a processor of the portable computer is fully operational. A "doze-mode"
is a mode in which a processor is operating fewer functions to conserve
energy.
For example, in the doze-mode, a display may be on, but a user may experience
a pause between the time an input in entered and processed. In the "sleep-
mode", the portable computer is in its lowest state of power consumption,
where
the display is off and a processor is performing minimal functions such as
time-
keeping.
For purposes of this description, a portable computer is a combination of
a processor coupled to a memory. A portable computer is a computer having a
portable energy resource. Handheld computers are portable computers designed
to be used with one hand.
Portable Computer and Accessory Device
With reference to FIG. 1 an embodiment of this invention includes a
portable computer 100 and an accessory device. Preferably, the portable
computer 100 has interactive hardware and software that perform functions such
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as maintaining calendars and phone lists. The portable computer 100 shown in
FIG. 1 includes a plurality of input functions keys 115 and a display 114
having
graphic user interface features. The display 114 may be provided with an
interface that allows the user to select and alter displayed content using a
pointer such as a stylus. In an embodiment, the display 114 also includes a
GraffitiTM writing section 118 for tracing alphanumeric characters as input. A
plurality of application buttons 117 for performing automated or pre-
programmed functions may be provided on a portion of the display 114. The
portable computer 100 may also include an antenna for receiving wireless
communications. An example of a suitable portable computer 100 for use with
embodiments of this invention include handheld computers such as
PalmPilotTM, Palm IIITM, Palm IVTM, Palm VTM organizers, manufactured by the
3Com Corporation. Other embodiments of the invention can include Windows
CETM portable computers, or other handheld computers and personal digital
assistants.
The stylus for inputting information onto the display 114 may slideably
mount to a rail (not shown) on one of the lateral sides 122 of the portable
computer 100. In an embodiment, the rail may be provided with logic and
electromechanical switches to perform functions based on the movement and
position of the stylus. The rail may provide an "on/ofF' function, where
removal of the stylus activates the portable computer 100 for user operation.
For example, removal of the stylus may actuate a switch (not shown)
implemented with the rail to activate the portable computer 100. The switch
may be formed from an electromagnetic coupling between a metal stylus and a
conductive element on the rail, where removal of the stylus forces a current.
In
another embodiment, a spring having a conductive surface may biasly obstruct
the path of the stylus along the rail, so that removal of the stylus alters
the
length of the spring to close the switch.
As will be further described, the accessory device may include a plug-in
communication cradle 150 having a parallel port for data transfer with a data
network or another computer. Other embodiments may provide for another type
of accessory device that equips the portable computer 100 with, for example,
serial communication abilities as provided by a modem device or Universal
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Serial Bus (USB) cradle. The communication cradle 150 includes a stand 152,
and an A/C adapter 160 that extends electricity from an external socket to
power the portable computer 100. The communication cradle 150 also includes
one or more ports for parallel and/or serial data transfer with other
computers or
data networks. The portable computer 100 may use the communication cradle
150 for the purpose of downloading and uploading software, and for
synchronizing data on the portable computer 100 with a personal computer (not
shown, but may be included or used with some embodiments of the invention).
The communication cradle 150 couples to the portable computer 100 through a
connector (see FIGS. 2-4) of the stand 152. A button 155 may effectuate an
electrical connection between the communication cradle 150 and the portable
computer 100 when the two are connected.
In an embodiment, the portable computer 100 includes hardware and/or
software to detect whether the communication cradle 150 is actively connected
1 S to the portable computer 100. One advantage provided by this embodiment is
that software on the portable computer 100 may be altered and/or reconfigured
to optimize functions of the portable computer 100 according to whether the
accessory device is actively connected. In this way, the portable computer 100
may launch programs that are practical only when external power is available.
FIG. 1 shows that the portable computer 100 may, for example, run a program
to continuously display a world-clock on the display 114 when the
communication cradle 150 is detected. Importantly, in this example, the type
of
accessory device indicates that the power is being supplied from an external
source so leaving the portable computer 100 does not drain the battery.
The portable computer 100 also accommodates alternative types of
accessory devices, such as a modem port or a USB cradle. An embodiment of
the portable computer 100 under this invention may include resources to detect
a type of accessory, and may further alter or reconfigure software to
accommodate the specific accessory type without requiring user input. This
feature safeguards against the portable computer 100 being prompted to execute
an application for the wrong accessory device. For some accessory devices such
as USB cradles, the accessory device may be damaged if the portable computer
executes an application for another type of accessory device such as a modem
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port. This invention provides that the portable computer 100 will run the
correct application for a particular accessory type. For example, the portable
computer 100 will not execute the modem application if the accessory device is
a USB device or cradle. In this manner, the portable computer 100 may
implement software for a particular accessory type with minimal user
attention,
while precluding the possibility of running a program for the wrong accessory
device.
Detecting an Accessory Device
FIG. 2 is an illustrative block diagram showing additional details of an
embodiment of the portable computer 100 connected to communicate with an
exemplary accessory device. In the embodiment shown by FIG. 2, the
accessory device is the plug-in communication cradle 150 having a parallel
communication port for coupling the portable computer 100 to an external
processor. The communication cradle includes an integrated A/C adapter for
operating the portable computer 100 independent of an internal battery source.
With further reference to the embodiment of FIG. 2, the portable
computer 100 includes a processor 210, a memory, and a battery source 230.
Preferably, the processor 210 is a Motorola EZ Dragonball 328TM processor,
and the memory 215 is a separate component that provides Random Access
Memory (RAM). The battery source 230 internally powers the processor 210
and memory 215, as well as other electrical components within the portable
computer 100. The battery source 230 may be standard disposable batteries, or
rechargeable such as Lithium-ion batteries. The portable computer 100 also
includes a communication port 232 having a pin connector for coupling to a
mating pin connector accessible in an output port 272 of the communication
cradle 150.
The processor 210 extends a signal line 205 to a pin element of the pin
connector of the output port 272. The portable computer 100 and
communication cradle 150 may electrically connect using only some of the pin
elements of the respective pin connectors. For example, the communication port
232 may include a ten pin male connector, where nine pins are designated for
functions such as parallel data transfer, parity, and "hot sync" functions for
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coupling the portable computer 100 with another computer. One remaining pin
is available for coupling without affecting the remaining pins. The example
shown in FIG. 2 couples the available pin to the signal line 205. In one
configuration, the signal line 205 and the available pin are initially pulled
high
using a pull-up resistor. When the pin connector is mated to electrically
connect
with the communication cradle 150, the pin and signal line 205 are pulled low.
The change in voltage on the signal line 205 signals the processor 210 that an
electrical connection between the communication cradle 1 SO and portable
computer 100 is established. The processor 210 may then execute a program
based on the accessory device being actively connected to the portable
computer 100.
The programs executed by the processor 210 include certain software
applications that preserve battery resources. The portable computer 100 may
have a time-out feature designed to significantly reduce the power consumption
of the device when the portable computer is inactive or not in use. In
general,
the time-out feature operates by switching the portable computer 100 from a
state of high power consumption to a state of low power consumption when the
portable computer detects inactivity for a predetermined duration of time.
Portable computers typically use some power at all times for the purpose
of maintaining a clock, memory etc. Therefore, the portable computer 100 may
include multiple states of power consumption, rather than just the "on" and
"off' mode. The states of the portable computer may include the "doze-mode"
in which the display 114 is powered, but some resources within the portable
computer 100 have stopped. The states of the portable computer 100 may also
typically include a "sleep-mode', where the portable computer 100 is
consuming significantly less power, but performing a few limited functions
such as maintaining the clock.
The time-out feature provides that the portable computer 100 enters a
state of low power consumption such as the sleep-mode if the processor 210 is
substantially inactive after a predetermined time-period. For example, the
known art provides that the portable computer 100 may time-out into the sleep-
mode when user activity ceases for more than two minutes. In devices such as
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PalmPilotTM organizers, the time-out feature may be programmed by the user to
vary between one and three minutes.
In an embodiment of the invention, a change in voltage on the signal line
205 may signal the processor 210 to alter a portion of a program and execute
code for suspending or prolonging the occurrence of the time-out feature. In
one embodiment of this invention, the portable computer 100 has a switch to
alternatively allow the user to selectively override the normal behavior of
the
time-out function when the communication cradle 150 is active. The portable
computer 100 may also detect the change in the voltage on the signal line 205
for the purpose of informing the user that the communication cradle 150 is
actively connected.
One advantage of suspending the time-out feature includes allowing the
user to continually access the portable computer 100 without having to switch
it
on.
Disabling the time-out feature, or otherwise modifying the time-out
feature, also allows the portable computer 100 to be optimized for certain
software applications that either require minimal user interface or require
proportionately greater amounts of power. Examples of such applications
include energy intensive software programs that have functions outside
traditional function such as of maintaining a calendar and phone numbers. For
example, the portable computer 100 may include software for displaying digital
photographs. Suspending the time-out feature enables the portable computer
100 to be used as a picture frame. Other examples of software applications
that
may be launched when the portable computer 100 has access to plug-in power
include games, a world clock display, or a computer desktop companion.
Suspending the time-out feature may also be used to execute applications that
continuously communicate with and/or display information from a data
network. Such applications may be used to display information such as a stock
market ticker.
In another embodiment of the invention, the change in voltage on the
signal line 205 resulting from coupling the communication cradle 150 may
signal the processor 210 to alter a portion of a program for suspending or
prolonging a time-out for a backlight display. Previous portable computers
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provide for the software control program to turn the backlight off to conserve
battery power. In this embodiment, the backlight may be continuously powered
when the processor 210 detects the communication cradle 150. Alternatively,
the backlight can be selectively turned on or off independent of the display
screen when the processor 210 determines that the communication cradle 150 is
electrically connected to the portable computer 100.
By detecting whether an accessory device is actively connected, the
processor 210 may also alter or reconfigure software to provide an alternative
software arrangement for routine uses of the portable computer 100. For
example, the processor 210 may be programmed to interpret the presence of an
actively connected communication cradle 150 as representing a "home"
position. In response to detecting an actively connected communication cradle
150, the processor 210 may alter or reconfigure the software to more readily
accommodate a home default position. The software may, for example, be
altered to redisplay a database in a new order. Accordingly, the portable
computer 100 may list personal phone numbers as a default file in a menu, and
list home finances as a default in a spreadsheet application, and display only
"to-do" tasks such as household chores. Then, when the portable computer 100
and the accessory device are not electrically connected the processor may run
software for a professional setting, including listing professional numbers
and
calendar items.
Detecting a Type of an Accessory Connected to the Portable Computer
FIG. 3 is a block diagram schematic of another embodiment of this
invention where a portable computer is equipped to distinguish different types
of accessories. In this embodiment, the portable computer 100 includes the
processor 210, analog-digital (A/D) converter 320, and the battery source 230.
The portable computer 100 also includes a memory 215 connected to the
processor 210. The processor 210 is preferably a Motorola EZ Dragonball
328TM that is connected to the A/D converter 320 via an 8-bit connection 312.
The A/D converter 320 preferably includes four channels. A first and second
channel 322 and 324 of the A/D converter 320 are dedicated for display
operations. A third channel 326 couples to the battery source 230. In this
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embodiment, a fourth channel of the A/D converter 320 is used as a signal line
328 to extend to a communication port 232 of the portable computer 100. The
A/D converter 320 couples to the battery source 230 via the third channel 326
to
receive a reference voltage for a comparator (not shown) incorporated within
the A/D converter 320. The communication port 232 may include a male pin
connector for coupling and electrically connecting with an accessory device.
In the embodiment of FIG. 3, an accessory device 350 provides a
constant voltage on an output node 365. The accessory device may be one of
several devices, including the communication cradle (shown by numeral 150 in
FIG. 1), modem devices and USB cradles. The output node 365 of the
accessory device 350 is accessed through an output port 272 to the pin
connector for the communication port 232. Previous systems provide for
coupling the portable computer 100 and accessory device 350 using only some
of the pin elements of the 10-pin connector. As mentioned in the embodiment
of FIG. 2, the communication port 232 provides a male pin connector with nine
pins designated for functions such as parallel data transfer and parity, and
one
pin being left available for alternative uses. Each type of accessory device
may
be assumed to have a unique constant voltage on a corresponding output node
that is accessible by the portable computer 100 through the communication port
232. Therefore, one improvement provided by some embodiments of this
invention includes coupling the available pin between the A/D converter 320
and the output node of an accessory device for the purpose of detecting and
distinguishing accessory devices from each other.
In an embodiment, the A/D converter 320 receives a reference voltage
from the battery source 230, and an input signal from the signal line 328
extending through the available pin of the communication port 232. The A/D
converter 320 may then (1) determine whether an accessory device is actively
connected to the portable computer 100 via the communication port 232, as
described in FIG. 2; and/or (2) determine the type of accessory device being
electrically connected to it.
The portable computer 100 and the accessory device 350 may be
connected so that the signal line 328 electrically contacts a mating pin in
the
output port 272 of the accessory device 350. When the accessory device 350 is
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powered, a voltage is provided on the output node 365 and to the signal line
328. The voltage on the signal line 328 is detected by the A/D converter 320.
A
comparator within the A/D converter 320 compares the voltage on the signal
line 328 with the reference voltage supplied from the battery source 230 via
the
third channel 326. The A/D converter 320 can signal the memory 215 for the
purpose of matching the voltage on the signal line 328 with a type of
accessory.
The voltages on the output node 365 of each type of accessory device may be
predetermined and stored in a look-up table of the memory 215. Therefore, the
look up may list accessory types according to the voltage on a corresponding
output node of each accessory type. Once the memory 215 is signaled, the
processor 210 may execute software to match the voltage on the signal line 328
with a type of accessory using the look-up table. For example, a modem port
may provide a voltage on an output node that is distinguishable from a voltage
on an output node of a communication cradle, such as the one shown in FIG. 1.
1 S Similarly, a USB cradle or device provides an output node having a
distinguishable voltage from the modem port or cradle.
Distinguishing between accessory devices in this manner enables the
portable computer 100 to select or alter programming to accommodate one
device over another in a quick and cost efficient manner. For example, the
portable computer 100 can immediately detect the presence of the USB cradle
and alter software to accommodate the USB cradle. This alteration to the
software can be done when the portable computer is in a doze-mode, so that the
user has quicker access to functions available from coupling the USB device.
In
another example, the portable computer 100 may be used to preclude
inadvertent detection of a modem port, because transmitting or altering
programs for a modem port that is not existent can be damaging to the system.
FIG. 4A is a block diagram schematic of another embodiment in which a
portable computer 100 is equipped to determine the type of accessory actively
connected to it. In this embodiment, the portable computer 100 includes a
processor 210, a memory 215, an analog-digital (A/D) converter 320, and a
battery source 230. As with the previous embodiment, the processor 210 is
preferably a Motorola EZ DragonballTM 328 that is connected to the A/D
converter 320 using an 8-bit connection 312. The memory 215 may store a
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look-up table similar to the embodiment of FIG. 3. The A/D converter 320
preferably includes four channels. A first and second channel 322 and 324 of
the A/D converter 320 are dedicated for display operations. A third channel
326
couples to the battery source 230. A fourth channel of the A/D converter 320
is
used as a signal line 328 to extend to a communication port 232 of the
portable
computer 100. The A/D converter 320 couples to the battery source 230 via the
third channel 326 to receive a reference voltage for a comparator (not shown)
incorporated within the A/D converter 320. The communication port 232 also a
male pin connector for coupling and electrically connecting with the accessory
device 350.
The accessory device 350 includes a voltage divider 460, and an output
port 272 for mating with the portable computer 100. As with previous
embodiments, the accessory device 350 may include one of many devices,
including a communication cradle 150, modem device, or USB cradle. The
1 S output port 272 includes a mating pin connector for the communication port
232. The voltage divider 460 includes an input node 462, a first resistor
series
464, and a second resistor series 466. One end of the second resistor 466
series
is tied to ground 468. An output node 465 is extended between the first
resistor
series 464 and the second resistor series 466. The output node 465 extends a
voltage to a corresponding pin slot on the output port 272. In this
embodiment,
a voltage of the input node 462 is tied to the battery source 230 of the
portable
computer 100 via a line 429.
The embodiment of FIG. 4A provides that the battery source 230 to feed
the reference voltage to both the A/D converter 320 and to the input of the
voltage divider 460. In this way, the voltage on the output node 465 may be
adjusted to account for fluctuations to the reference voltage supplied to the
A/D
converter 320. This enables the A/D converter 320 to more accurately detect
the voltage on the output node 465. Additional precision in determining the
voltage in turn allows for a larger and more accurate match between detected
voltages and corresponding device types. In this manner, the embodiment of
FIG. 4A may be employed to distinguish among different accessory types
similar to previous embodiments, but more accurately matches the voltage on
the signal line 328 with the matching accessory type. Employing an 8-bit A/D
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converter 320 in this manner allows for up to 256 different accessory types to
be
matched to a distinct voltage on the signal line 328.
FIG. 4B is an embodiment similar to FIG. 4A except that the voltage
divider 460 is now distributed between the portable computer 100 and the
accessory device 350. In this embodiment, the voltage of the output node 465
may be determined based on a resistor series contained within the accessory
device 350 that is tied to ground. The input node 462 and the first resistor
series
464 couple to the battery source 230 within the portable computer 100. A
voltage line 414 passes from the first resistor series 464 through the
communications port 232, the output port 272 and into the accessory device
350. The voltage line 414 couples with a second resistor series 464 connected
to ground 468 that forms the voltage divider 460. The voltage line 414 may be
passed through one of the pin elements of the pin connectors used to couple
the
portable computer 100 and accessory device 350, such as the second pin shown
in FIG. 2. FIG. 4B represents an alternative configuration in which the
accessory device supplies a voltage from the battery source to produce a
distinguishable voltage on the output node 465. Since the input voltage
provided to the accessory device 350 is the same as the reference voltage to
the
A/D converter 320, the A/D converter is able to better distinguish between
voltages on the output node 465.
Algorithm for Detecting an Accessory Device
FIG. 5 is a flowchart showing the steps by which a portable computer
device such as the one shown in FIG. 2 operates depending on whether an
accessory device such as the communication cradle 150 is actively connected to
it. In an embodiment of this invention, the algorithm described herein may be
implemented with the portable computer 100 and the communication cradle 150
supplying the portable computer 100. The communication cradle 150 described
with this embodiment is intended to only be an exemplary accessory device that
provides communication abilities and external power to the portable computer
100.
In step 510, the portable computer 100 receives a signal from the
communication cradle 150. This step may be accomplished by signaling to the
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processor 210 the voltage on the signal line 205. In step 515, the processor
210
determines whether the communication cradle 150 is actively connected to the
portable computer 100. This is preferably determined by a voltage on the
signal
line 205 being either high or low. In a corresponding embodiment, the signal
line 205 floats high and is pulled low when actively connected. Under this
configuration, the processor 210 determines that the communication cradle 150
is actively connected when the voltage on the signal line 205 is low.
If an accessory is detected, the portable computer 100 in step 520 alters
programming of the software to disable the time-out. To accomplish this step,
the processor 210 may execute programming to suspend or delay the time-out
feature from turning the portable computer to a state of reduced power
consumption. If an accessory is not detected, step 530 shows that the
processor
210 will resume normal operations, in which case the portable computer 100
turns off after a pre-programmed duration in which the time-out feature
becomes effective.
Algorithm for Detecting a Type of an Accessory Device
FIG. 6 is a flowchart showing the steps by which a portable computer
device such as the one shown in FIGS. 3-4 determines the type of accessory
device that is actively connected to it. For descriptive purposes, components
used to describe the flowchart may be referenced with respect to the assembly
shown by FIG. 4, so that the algorithm may be implemented with the portable
computer 100 and any one of the accessory devices disclosed herein, including
the communication cradle 150, modem device, and USB cradle.
In step 610, the signal from the accessory device is measured. This may
be accomplished using the A/D converter 320 to measure the voltage value of
the signal on the signal line 328.
In step 620, the algorithm determines the type of accessory by matching
the signal value to the accessory type, by for example, using a look-up table.
The A/D converter 320 may determine the voltage in counts, and the processor
210 then compares the counts to values stored in the look-up table. The look-
up
table is preferably stored in the memory 215. In step 620, the processor 210
performs steps of a program according to the type of accessory being connected
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to the portable computer 100. For example, the comparator will run a modem
application if a modem is detected by the signal line 328, or disable the time-
out
feature if the communicator cradle 150 is detected.
The portable computer 100 may detect anyone of n accessory types,
where n represents the number of voltage counts that the A/D converter can
detect. With an 8 bit connection between the A/D converter 320 and the
processor 210, the A/D converter may be used to detect up to 256 different
types of accessories. Other "types" of accessories that may be recognized by
the portable computer 100 include "no accessory", and an "unknown
accessory". A possible step 632 shows, for example, that if the voltage count
is
0, then no accessory is detected. The portable computer then resumes normal
operations in step 642, which assumes battery operation with no accessory
device.
The processor 210 may alternatively execute step 634, which shows an
"unknown" type of accessory for when the voltage determined by the A/D does
not match to a corresponding type of accessory in the look-up table.
Subsequently, step 644 shows that an error message is then displayed to notify
the user that the accessory device does not match the portable computer 100.
The processor may determine, in step 636, that a first type of accessory
device is actively connected to the portable computer 100. As shown by step
646, the processor 210 in step 646 alters the software by performing steps
that
accommodate the particular type of accessory. In possible steps 638 and 648,
the processor 210 detects from one of other types of accessories, and program
the portable computer to accommodate the particular accessory.
This invention is intended to encompass an embodiment combining the
steps shown in FIGS. S and 6. Therefore, under an embodiment of this
invention, a portable computer may determine first whether an accessory device
is connected to it, and next determine the type of accessory device that is
connected.
Alternative Embodiments
Several variations and additional features may be incorporated in
embodiments of this invention.
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PCT/US00/09014
For setting software depending on whether an accessory device such as a
communication cradle is actively connected to the portable computer, a switch
may be provided that switches the voltage on the signal line from high to low
or
vice versa. The switch may be used to set a software arrangement for routine
uses of the portable computer. In an embodiment, the switch may be used to
distinguish between identical communication cradles, where one of the
communication cradles is used for a first operational environment, and another
of the communication cradles is used for another operational environment.
Therefore, a user may assign one of the communication cradles to represent the
"home" position, where data is arranged to prioritize personal information
over
professional information. Similarly, the switch may distinguish the other
communication cradle to represent a "work" position, where the data
arrangement prioritizes professional information.
In an embodiment of the invention, software on the portable computer
100 may be configured or set to accommodate a particular type of accessory
device connected to the portable computer 100 even when the portable
computer is a sleep-mode. For example, a modem device may be connected to
the portable computer 100 in a sleep-mode. The portable computer 100 detects
the voltage on the signal line and sets a data value based on the modem
device.
When the portable computer 100 is subsequently switched to an "on" or "doze"
mode, the portable computer immediately makes the modem device available.
Minimizing access time in this manner may provide significant advantages to
portable computer s incorporating this embodiment of the invention, in that
use
of the portable computer is often intermittent and for relatively short
durations.
Conclusion
The foregoing description of various embodiments of the invention have
been presented for purposes of illustration and description. It is not
intended to
limit the invention to the precise forms disclosed. Many modifications and
equivalent arrangements will be apparent.
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