Memory life extension method and apparatus

• US 8,909,850 B2
• Filed: 03/10/2011
• Issued: 12/09/2014
• Est. Priority Date: 03/10/2011
• Status: Expired due to Fees

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Sopko, Tyge, Vilar, Zimin W., Gilman, Alan K.
• Primary Examiner(s): Bernard, Daniel J
• Application Number:
  US13/044,614
• Publication Number:
  US 20120232744A1
• Time in Patent Office: 1,370 Days
• Field of Search: None
• US Class Current: 711/103
• CPC Class Codes: G06F 12/16 Protection against loss of memory contents contains no material, see G06F11/00
• CPC Class Codes: G06F 13/16 for access to memory bus G06F13/28 takes precedence
• CPC Class Codes: G11C 16/3495 Circuits or methods to detect or delay wearout of nonvolatile EPROM or EEPROM memory devices, e.g. by counting numbers of erase or reprogram cycles, by using multiple memory areas serially or cyclically

Abstract

A memory management method including the steps of storing a value and writing data. The storing a value step stores a value representative of a number of erase/write cycles that a subset of memory space of a first memory has undergone. The first memory having an assigned predetermined maximum number of erase/write cycles. The writing data step writes data to the subset of memory space dependent upon whether the value is below the predetermined maximum number.

Claims

1. A memory management method, comprising the steps of:

storing, via a controller embedded in a vehicle, a power cycle value representative of a number of power cycles that a first subset of memory space of a first memory has undergone, said first memory having an assigned predetermined maximum number of erase/write cycles, wherein said power cycle value is stored in a second memory that has an assigned predetermined maximum number of erase/write cycles which is larger than said predetermined maximum number of said first memory;

writing, via said controller, data to said first subset of memory space dependent upon whether said power cycle value is below said predetermined maximum number; and

storing, via said controller, in said second memory, a location value representative of a memory location of said first memory at which data is currently being stored;

wherein said first and second memories are external to said controller and are embedded in said vehicle;

wherein said first subset of memory space includes multiple memory sectors having a first range of addresses;

wherein said writing step includes writing data to a new subset of memory space if said power cycle value is one of equal to and greater than said predetermined maximum number;

wherein said new subset of memory space includes multiple memory sectors having a second range of addresses different from said first range of addresses; and

wherein when said data written to said new subset of memory space is different from historical data previously written to said first subset of memory space, and said historical data is preserved in said first subset of memory space.

2. The method of claim 1, further comprising the step of storing an offset value which is used to determine a memory location of said first memory at which data can be stored.

3. The method of claim 2, wherein said offset value is stored in said second memory.

4. An electrical control system, comprising:

a control unit having, a microcontroller embedded in a vehicle, a first memory and a second memory, said first memory and said second memory being in communication with said microcontroller and embedded in said vehicle, said control unit using a memory management method that includes the steps of;

storing, in said second memory, a power cycle value representative of a number of power cycles that a first subset of memory space of said first memory has undergone, said first memory having an assigned predetermined maximum number of erase/write cycles;

writing data to said first subset of memory space dependent upon whether said power cycle value is below said predetermined maximum number; and

storing, in said second memory, a location value representative of a memory location of said first memory at which data is currently being stored;

wherein said second memory has an assigned predetermined maximum number of erase/write cycles which is larger than said predetermined maximum number of said first memory;

wherein said first and second memories are external to said microcontroller;

wherein said first subset of memory space includes multiple memory sectors having a first range of addresses;

wherein said writing step includes writing data to a new subset of memory space if said power cycle value is one of equal to and greater than said predetermined maximum number;

wherein said new subset of memory space includes multiple memory sectors having a second range of addresses different from said first range of addresses; and

wherein when said data written to said new subset of memory space is different from historical data previously written to said first subset of memory space, and said historical data is preserved in said first subset of memory space.

5. The electrical control system of claim 4, wherein the method further comprises the step of storing an offset value which is used to determine a memory location of said first memory at which data can be stored, said offset value being stored in said second memory.

6. An energy consuming device, comprising:

at least one performance measuring device that produces at least one measured value;

a first memory device;

a second memory device; and

a controller communicatively coupled to the energy consuming device, said controller being in communication with said first memory device and said second memory device, which memory devices are external to said controller, said at least one measured value being stored in a first selected location in said first memory device, said first memory device having an assigned predetermined maximum number of erase/write cycles, said first selected location being changed to a new selected location once said first memory device has undergone a count of power cycles that is equal to said predetermined maximum number of erase/write cycles, said second memory device containing said count;

wherein said second memory device has an assigned predetermined maximum number of erase/write cycles that exceeds said predetermined maximum number of erase/write cycles of said first memory device;

wherein a location value representative of said first selected location and an offset value are stored in said second memory, said offset value being used to determine a memory location of said first memory device at which said at least one measured value is stored;

wherein the energy consuming device is configured to power a vehicle and said controller and said first and second memory devices are embedded in said vehicle;

wherein said first selected location includes multiple memory sectors having a first range of addresses;

wherein said new selected location includes multiple memory sectors having a second range of addresses different from said first range of addresses; and

wherein said data written to said new selected location is different from historical data previously written to said first selected location, and said historical data is preserved in said first selected location.

7. The energy consuming device of claim 6, wherein said second memory device has an assigned predetermined maximum number of erase/write cycles that is more than ten times said predetermined maximum number of erase/write cycles of said first memory device.