Method for completely reprogramming an erasable, non-volatile memory

• US 5,712,969 A
• Filed: 11/30/1995
• Issued: 01/27/1998
• Est. Priority Date: 09/24/1993
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Zimmermann, Jurgen, Grote, Walter
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Baderman, Scott T.
• Application Number:
  US08/553,685
• Time in Patent Office: 789 Days
• Field of Search: 395/182.03, 395/182.01, 395/185.01, 395/182.04, 395/182.05, 371/40.4, 364/244.4
• US Class Current: 714/5.1
• CPC Class Codes: G05B 19/0426 Programming the control sequence
• CPC Class Codes: G06F 8/654 using techniques specially adapted for alterable solid state memories, e.g. for EEPROM or flash memories
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 16/102 External programming circuits, e.g. EPROM programmers; In-circuit programming or reprogramming; EPROM emulators
• CPC Class Codes: G11C 16/105 Circuits or methods for updating contents of nonvolatile memory, especially with 'security' features to ensure reliable replacement, i.e. preventing that old data is lost before new data is reliably written

Abstract

A method for completely reprogramming an erasable, non-volatile memory (12) in a control device (10) is presented. The control device (10) has at least one central unit (11), a volatile memory (13), an erasable, non-volatile memory (12) and also input/output circuits (15). The data to be programmed are transferred from an external electronic device (18), such as a personal computer for example, to the control device (10). The control device then programs the received data itself into the erasable, non-volatile memory. With the method, the erasable, non-volatile memory (12) is divided into two areas (20, 21) that can be erased and programmed separately. Before the actual programming operation a programming module is written in each case into each area (20, 21). To reprogram the erasable, non-volatile memory (12), the programming module is written into at least one of the areas (20, 21) that can be erased and programmed separately. The programming of one of the two areas (20, 21) takes place only if the programming module is written in the other of the two areas (20, 21) that can be erased and programmed separately.

Claims

1. A method for completely reprogramming an erasable, nonvolatile memory in a control device, said method comprising the steps of:

a) providing a control device (10) containing at least one central unit (11), a volatile memory (13), an erasable, nonvolatile memory (12) and input/output circuits (15), wherein said erasable, nonvolatile memory (12) comprises at least two separately erasable and programmable areas(20,

     21) and at least one first area (20) of said at least two separately erasable and programmable areas (20,

     21) includes an error-free programming module for programming the erasable, nonvolatile memory (12) stored therein;

b) providing an external electronic device (18) containing data to be programmed in the erasable, nonvolatile memory (12);

c) executing said programming module for programming of the erasable, nonvolatile memory (12) provided in step a) under control of the at least one central unit (11), thereby receiving said data in the erasable, nonvolatile memory from said external electronic device (18);

d) during said programming of the erasable, nonvolatile memory (12) in step c), first programming a second area (21) of said at least two areas (20,

     21) of the erasable, nonvolatile memory (12) and thereby programming another programming module into said second area (21); and

e) reprogramming said at least one first area (20) with said another programming module already stored in said second area (21).

2. The method as claimed in claim 1, further comprising transferring the programming module from the at least one first area (20) of the erasable, nonvolatile memory (12) to the volatile memory (13), and subsequently beginning the executing of the programming module in the volatile memory under control of the at least one central unit (11).

3. The method as claimed in claim 1, wherein the programming module comprises means for communicating with the external electronic device (18), means for checking access authorization of the external electronic device (18), means for loading the programming module into the volatile memory (13) and means for erasing and for programming the erasable, nonvolatile memory (12).

4. The method as claimed in claim 2, wherein the programming module includes at least two of means for communicating with the external electronic device (18), means for checking access authorization of the external electronic device (18), means for loading the programming module into the volatile memory (13) and means for erasing and for programming the erasable, nonvolatile memory (12);

and further comprising writing each of said means not included in said programming module into the volatile memory (13) from the external electronic device (18).

5. The method as claimed in claim 1, further comprising calculating a checksum for checking the memory contents of the at least one first area (20), comparing the checksum with a value entered in the erasable, nonvolatile memory (12), and identifying said memory contents as error-free if the checksum matches the value entered in the erasable, nonvolatile memory (12).

6. The method as claimed in claim 1, further comprising checking one of said at least two separately erasable and programmable areas (20, 21) after said one of said at least two separately erasable and programmable areas (20, 21) has been programmed to determine if contents of said one of said at least two separately erasable and programmable areas (20, 21) are error-free, and only programming a next one of said at least two separately erasable and programmable areas (20, 21) if said contents of said one of said least two separately erasable and programmable areas (20, 21) are identified as error-free, and repeating the programming of said one of said at least two separately erasable and programmable areas (20, 21) if said contents of said one of said at least two separately erasable and programmable areas (20, 21) are not error-free.

7. The method as claimed in claim 1, further comprising storing a control program for the control device (10) together with the programming module into two of the at least two separately erasable and programmable areas (20, 21) of the erasable, nonvolatile memory (12), when said control device (10) is at an end of a production line for the control device (10).

8. The method as claimed in claim 1, further comprising storing the programming module into only one of said at least two separately erasable and programmable areas (20, 21) of the erasable, nonvolatile memory (12) when said control device (10) is at an end of a production line for the control device (10), and writing the programming module into another of the at least two separately erasable and programmable areas (20, 21) of the erasable, nonvolatile memory (12) before the programming module in the said one of said at least two separately erasable and programmable areas (20) is erased.

9. The method as claimed in claim 1, further comprising providing the control device with means for controlling a motor vehicle.