EP0766167A1
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EP
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Power management of an information processing system
Assignee: International Business Machines Corp
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Filing: 1996-09-16
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Granted: —
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Expires: 2016-09-16
Abstract
Abstract An information processing system achieves power saving by reducing the operating frequency of a CPU, or halting the operation of the CPU, in response to monitoring of a bus cycle. Power is saved when asynchronous communication is performed with peripheral devices. Power is also saved when the system is engaged in exchanging data with another independent apparatus (e.g., another PC) via a communication port (a serial port or a parallel port), or when a communication application is being executed. The information processing system switches a CPU between a normal mode and a power saving mode in which the power consumption is lower than that of the normal mode in response to bus cycle detection means for monitoring a bus cycle on a bus that is employed for communication between the CPU and a peripheral device and determination by condition determination means of the appropriate operation mode.
Inventors
- 👤 Takashi Inui
- 👤 Seiichi Kawano
- 👤 Shinji Matsushima
- 👤 Masayoshi Nakano
- 👤 Yuichi Shiraishi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 15:19
CPC Classifications
G; G06; G06F; G06F1/00; G06F1/26; G06F1/32; G06F1/3203; G06F1/3206; G06F1/3215
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
109 words
An information processing system comprising: a CPU (11) having at least two operation modes, a normal mode and a power saving mode; at least one peripheral device (21,27); a bus (16) employed for communication between said CPU and said peripheral device; bus cycle detection means (50a) for monitoring a bus cycle on said bus; condition determination means (50b) for determining an operational mode of said CPU in a specific bus cycle that is detected by said bus cycle detection means; and signal generation means (50c) for providing, to said CPU, a control signal for changing between operational modes in accordance with a determination result by said condition determination means.
Claim 2
Dependent Claim
80 words
The information processing system according to claim 1, wherein said bus cycle detection means detects a predetermined bus cycle in which an activity of said CPU is reduced, said condition determination means determines said operational mode of said CPU to be a power saving mode in accordance with the detected result by said detecting means, and, in accordance with said determination result, said signal generation means provides a control signal to cause said CPU to enter a power saving mode.
Claim 3
Dependent Claim
40 words
The information processing system according to claim 2, wherein said bus cycle detection means detects a bus cycle for counting the timing of a handshaking operation as said predetermined bus cycle in which the activity of said CPU is reduced.
Claim 4
Dependent Claim
55 words
The information processing system according to claim 2, further comprising at least a hard disk drive as said peripheral device, wherein said bus cycle detection means detects a bus cycle in which data port for said hard disk drive is accessed as said predetermined bus cycle in which the activity of said CPU is reduced.
Claim 5
Dependent Claim
61 words
The information processing system according to claim 2, further comprising, as said peripheral devices, at least a floppy disk controller and a floppy disk drive, wherein said bus cycle detection means detects a bus cycle in which a status register of said floppy disk controller is accessed as said predetermined bus cycle in which the activity of said CPU is reduced.
Claim 6
Dependent Claim
58 words
The information processing system according to claim 3, wherein, in accordance with a detection of said bus cycle, said condition determination means shifts the operational mode of said CPU to a power saving mode, and inhibits a return to a normal mode until a bus cycle other than said previously detected bus cycle is detected twice in succession.
Claim 7
Dependent Claim
53 words
The information processing system according to claim 4 or claim 5 wherein said condition determination means shifts the operational mode of said CPU to said power saving mode, in accordance with said detection result for said bus cycle, and returns said operating mode to said normal mode when another bus cycle is detected.
Claim 8
Dependent Claim
42 words
The information processing system according to any preceding claim wherein said power saving mode is an operating mode in which a frequency of an operational clock for at least one unit part inside said CPU is reduced or an operation is halted.
Claim 9
Dependent Claim
135 words
An information processing system as claimed in any preceding claim in which said CPU also has a stop mode in which operation is completely halted; the system further comprising a communication port (24,25), physically connectable to another independent apparatus, for performing data transfer; state determination means for determining an operational mode of said CPU in response to a detection by said bus cycle of access of said communication port; said signal generation means providing, when said state determination means ascertains that said operational mode is to be the power saving mode, a control signal to said CPU to set said CPU to the power saving mode; and CPU operation halting means for completely halting an operation of said CPU when said state determination means ascertains that said operational mode is to be the stop mode.
Claim 10
Dependent Claim
49 words
The information processing system according to claim 9, wherein said state determination means determines that said operational mode should be the power saving mode when a first predetermined time has elapsed since a last bus cycle for accessing the data port of said communication port during the normal mode.
Claim 11
Dependent Claim
54 words
The information processing system according to claim 9, wherein said state determination means determines that said operational mode should be the stop mode when a second predetermined time has elapsed since a last bus cycle for setting or cancelling a control value for data transfer via said communication port during the power saving mode.
Claim 12
Dependent Claim
44 words
The information processing system according to claim 9, wherein said state determination means determines that said operational mode should be the normal mode upon the occurrence of a bus cycle for accessing a data port of said communication port during the power saving mode.
Claim 13
Dependent Claim
51 words
The information processing system according to claim 9, wherein said state determination means determines that said operational mode is to be the power saving mode upon the occurrence of a bus cycle for setting or cancelling a control value for said data transfer via said communication port during the stop mode.
Claim 14
Dependent Claim
55 words
The information processing system according to any one of claims 9 to 13 further comprising: power saving control means for activating either said signal generation means or said CPU operation halting means in accordance with both a monitoring result obtained by said CPU monitoring means and a determination result obtained by said state determination means.
Claim 15
Dependent Claim
52 words
The information processing system according to claim 14, wherein, during a period that said state determination means permits said CPU to enter to the power saving mode, said power saving control means activates said signal generation means in response to the detection by said CPU monitoring means that said CPU is idle.
Claim 16
Dependent Claim
51 words
The information processing system according to claim 14, wherein, during a period that said state determination means permits said CPU to enter the stop mode, said power saving control means activates said CPU operation halting means in response to the detection by said CPU monitoring means that said CPU is idle.
Claim 17
Dependent Claim
52 words
The information processing system according to claim 14, wherein, during a period that said state determination means inhibits said CPU from entering the power saving mode, said power saving control means does not activate said signal generation means regardless of the detection by said CPU monitoring means that said CPU is idle.
Claim 18
Dependent Claim
52 words
The information processing system according to claim 14, wherein, during a period that said state determination means inhibits said CPU from entering the stop mode, said power saving control means does not activate said CPU operation halting means regardless of the detection by said CPU monitoring means that said CPU is idle.
References Cited (Backward Citations)
US5404546A
Cited
US5369771A
Cited
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