Print engine having authentication device for preventing multi-word memory writing upon power drop

• US 7,747,887 B2
• Filed: 05/16/2007
• Issued: 06/29/2010
• Est. Priority Date: 12/02/2002
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Shipton, Gary, Walmsley, Simon Robert
• Primary Examiner(s): Du; Thuan N
• Application Number:
  US11/749,750
• Publication Number:
  US 20080259711A1
• Time in Patent Office: 1,140 Days
• Field of Search: 713/300, 713/340, 365/226, 365/228, 365/195, 365/229, 711/163, 711/152, 714/22, 358/1.14, 324/76.11, 702/64
• US Class Current: 713/340
• CPC Class Codes: B41J 2/04505 aiming at correcting alignment
• CPC Class Codes: B41J 2/04508 aiming at correcting other parameters
• CPC Class Codes: B41J 2/0451 for detecting failure, e.g. clogging, malfunctioning actuator
• CPC Class Codes: B41J 2/04528 aiming at warming up the head
• CPC Class Codes: B41J 2/04541 Specific driving circuit
• CPC Class Codes: B41J 2/04543 Block driving
• CPC Class Codes: B41J 2/04563 detecting head temperature; Ink temperature
• CPC Class Codes: B41J 2/04573 Timing; Delays
• CPC Class Codes: B41J 2/04586 controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type
• CPC Class Codes: B41J 2202/20 Modules
• CPC Class Codes: G06F 21/554 involving event detection and direct action
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: G06F 21/575 Secure boot
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 21/71 to assure secure computing or processing of information
• CPC Class Codes: G06F 21/73 by creating or determining hardware identification, e.g. serial numbers
• CPC Class Codes: G06F 21/74 operating in dual or compartmented mode, i.e. at least one secure mode
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H03K 5/1252 Suppression or limitation of noise or interference specially adapted for transmission systems H04B15/00, H04L25/08
• CPC Class Codes: H04N 1/405 Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
• CPC Class Codes: Y10S 707/99933 : Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99939 : Privileged access
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

A print engine comprising at least one print controller and at least one associated authentication device is provided. Each authentication device has a processor, non-volatile memory, an input for receiving power from a power supply and a power detection unit. Each authentication device is configured to enable multi-word writes to the non-volatile memory under control of the associated print controller. The processor is configured to control and trim the amount of power supplied to the input to predetermine a threshold at which operation of the authentication device is established. The power detection unit is configured to monitor a voltage level of the power supplied to the input, and in the event the voltage level drops below the predetermined threshold, preventing subsequent words in any multi-word write currently being performed from being written to the memory.

Claims

1. A print engine comprising at least one print controller and at least one associated authentication device, each authentication device having a processor, non-volatile memory, an input for receiving power from a power supply and a power detection unit, wherein each authentication device is configured to enable multi-word writes to the non-volatile memory under control of the associated print controller,

wherein the processor is configured to control and trim the amount of power supplied to the input to predetermine a threshold at which operation of the authentication device is established;

and

the power detection unit is configured to monitor a voltage level of the power supplied to the input, and in the event the voltage level drops below the predetermined threshold, preventing subsequent words in any multi-word write currently being performed from being written to the memory.

2. A print engine as claimed in claim 1, wherein the power detection unit is configured to prevent any further writes of any type to the memory once the voltage level is determined to have dropped below the threshold.

3. A print engine as claimed in claim 1, wherein the power detection unit is configured to provide a reset signal to at least some other circuits of the authentication device once any current writes have been finished.

4. A print engine as claimed in claim 1, wherein the memory is flash memory.