Electronic apparatus and control method thereof

• US 7,660,975 B2
• Filed: 11/28/2005
• Issued: 02/09/2010
• Est. Priority Date: 11/29/2004
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nakamura, Hidenori, Nakamiya, Shinji
• Primary Examiner(s): Lee; Thomas
• Assistant Examiner(s): Abbaszadeh; Jaweed A
• Application Number:
  US11/287,238
• Publication Number:
  US 20060129883A1
• Time in Patent Office: 1,534 Days
• Field of Search: 713/1, 713/300, 368/64, 714/2, 714/48
• US Class Current: 713/1
• CPC Class Codes: G06F 1/24 Resetting means

Abstract

An electronic apparatus wherein an abnormal control routine of the control unit can be prevented, or an abnormal control routine that has been started by the control unit can be rapidly halted is provided. An electronic apparatus having a control unit, peripheral circuits whose operations are controlled by the control unit, and a rechargeable battery for feeding operation power to the control unit and the peripheral circuits, wherein an initialization signal RT4 is continuously output to the control unit during a period of time (during time t1 to t4) that the voltage fed to the control unit is equal to or less than the voltage V1 for assured operation of the control unit, and is equal to or greater than the start voltage VX for starting the operation of the control unit.

Claims

1. An electronic apparatus having a control unit, peripheral circuits having operations controlled by said control unit, and a rechargeable battery being configured to feed operational power to said control unit and said peripheral circuits, said electronic apparatus comprising:

a continuous initialization device configured to initialize said control unit; and

a abnormality detector configured to detect abnormalities in said control unit,

said continuous initialization device outputting an first initialization signal to said control unit during at least one of a first and a second periods of time, said first period of time being when voltage supplied to said control unit is equal to or less than operation-assured voltage of said control unit, and is equal to or greater than start voltage to start operation of said control unit, said second period of time being when said voltage supplied to said control unit is greater than the lower limit of operation-assured voltage of said peripheral circuits and lower than said start voltage to start said operation of said control unit,

said continuous initialization device outputting a second initialization signal to said control unit when an abnormality is detected at said control unit.

2. The electronic apparatus according to claim 1, wherein

the continuous initialization device outputs a third initialization signal to said control unit when the voltage fed to said control unit is equal to or greater than the lower limit of operation-assured voltage of said peripheral circuits.

3. The electronic apparatus according to claim 1, further comprising

a charging control device to charge said rechargeable battery with power fed from said power supply,

a voltage generation device to generate voltage by using said power supply, and

a service voltage buildup device to accumulate voltage supplied to said control unit on the basis of voltage obtained by adding the voltage generated by said voltage generation device and the voltage of said rechargeable battery, until the voltage of said rechargeable battery exceeds at least the operation-assured voltage of said control unit.

4. The electronic apparatus according to claim 3, wherein said service voltage buildup device further accumulates voltage fed to said control unit on the basis of voltage obtained by adding the voltage generated by said voltage generation device and the voltage of said rechargeable battery, when said abnormality detector detects an abnormality in said control unit.

5. The electronic apparatus according to claim 4, wherein said peripheral circuits include

an oscillation circuit outputting a clock signal, and

a clock control device to switch-control feeding and suspension of the clock signal to said control unit, wherein

said clock control device stops feeding the clock signal to said control unit when said control unit has executed a control unit halt command, and starts feeding said clock signal to said control unit when said peripheral circuits issue an interrupt to said control unit, or when said continuous initialization device begins outputting said first or second initialization signal.

6. The electronic apparatus according to claim 5, wherein

said peripheral circuits are provided with a timing device to measure time, and the electronic apparatus is configured as a clock equipped with a time display to display time on the basis of the timing results of said timing device.

7. The electronic apparatus according to claim 2, wherein

said peripheral circuits are provided with a timing device to measure time, and the electronic apparatus is configured as a clock equipped with a time display to display time on the basis of the timing results of said timing device.

8. A control method for an electronic apparatus having a control unit, peripheral circuits having operations controlled by the control unit, and a rechargeable battery for feeding operation power to the control unit and the peripheral circuits, said method comprising:

outputting a first initialization signal to the control unit during at least one of a first and a second periods of time, said first period of time being when voltage fed to the control unit is equal to or less than operation-assured voltage of the control unit, and is equal to or greater than start voltage for starting the operation of the control unit, said second period of time being when said voltage supplied to said control unit is greater than the lower limit of operation-assured voltage of said peripheral circuits and lower than said start voltage to start said operation of said control unit;

outputting a second initialization signal to said control unit when an abnormality is detected at said control unit.

9. A control method for an electronic apparatus having a control unit, peripheral circuits having operations controlled by the control unit, and a rechargeable battery feeding operation power to the control unit and the peripheral circuits, the rechargeable battery being charged by electricity fed from a power supply, comprising:

making a determination whether an abnormality has occurred in the control unit;

outputting a first initialization signal to said control unit during at least one of a first and second periods of time, said first period of time when voltage supplied to said control unit is equal to or less than operation-assured voltage of said control unit, and is equal to or greater than start voltage to start operation of said control unit, said second period of time when said voltage supplied to said control unit is greater than the lower limit of operation-assured voltage of said peripheral circuits and lower than said start voltage to start said operation of said control unit;

outputting a second initialization signal to the control unit when an abnormality is detected at said control unit;

generating voltage by the power supply; and

building up the voltage fed to the control unit on the basis of voltage obtained by adding the generated voltage and the voltage of the rechargeable battery.