Implantable medical stimulation device having reconfigurable memory

• US 6,704,601 B1
• Filed: 08/09/2001
• Issued: 03/09/2004
• Est. Priority Date: 08/09/2001
• Status: Expired due to Term

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Badelt, Steven W., Amely-Velez, Jorge N., Darbidian, Dro
• Primary Examiner(s): Schaetzle, Kennedy
• Assistant Examiner(s): DROESCH, KRISTEN L
• Application Number:
  US09/927,758
• Time in Patent Office: 943 Days
• Field of Search: 607/30-32, 607/59-60
• US Class Current: 607/59
• CPC Class Codes: G06F 12/0638 Combination of memories, e.g. ROM and RAM such as to permit replacement or supplementing of words in one module by words in another module address formation of the next microinstruction G06F9/26; masking faults in memories by using spares or by reconfiguring G11C29/70
• CPC Class Codes: G06F 9/445 Program loading or initiating bootstrapping G06F9/4401; security arrangements for program loading or initiating G06F21/57

Abstract

The implantable medical device is provided with typically equal portions of both random access memory (RAM) and read only memory (ROM) and a virtual memory space is defined equal to the amount of memory in one of the memory devices. In a specific example, the RAM and ROM provide 256 K of memory each, with the virtual memory space also set to 256 K. A zone control register is provided which specifies, for each of a set of predetermined zones within the virtual memory space, whether memory access commands are to be routed to RAM or ROM. Control bits within the zone control register may be reset to permit portions of memory to be remapped from one memory device to the other. By providing RAM and ROM each typically equal in size to the virtual memory space, software for use in the device may be tested and debugged using RAM then transferred to ROM for use in production devices. By providing dual RAM and ROM, software upgrades or software bug fixes are easily performed merely by downloading new software into RAM, then resetting the zone control register to point to RAM, rather than ROM. Additionally, when necessary, the overall virtual memory space may be expanded to encompass both the RAM and ROM thereby permitting access to greater quantities of memory.

Claims

1. A method for use in controlling the operation of an implantable medical device wherein the device has a microcontroller capable of accessing a virtual memory space, a memory system including a dynamic memory unit and a static memory unit, with each memory unit having sufficient memory to accommodate the entire virtual memory space, and a memory controller for dynamically mapping selected portions of the virtual memory space to either the dynamic memory unit or the static memory unit, the method comprising the steps of:

loading the control software into the dynamic memory unit;

controlling the memory controller to direct memory access commands for accessing the control software to the dynamic memory;

testing the operation of the control software within the implantable medical device;

storing a final tested version of the control software in the static memory unit; and

controlling the memory controller to direct memory access commands for accessing the control software to the static memory.

2. The method of claim 1 further including the subsequent step of implanting the device within a patient for use therein.

3. The method of claim 1 wherein, if the final version of software within the static memory subsequently needs to be modified, loading modified software into the dynamic memory unit then resetting the memory controller to direct memory access commands for accessing the modified software to the dynamic memory.

4. A method for making and using an implantable medical device, the method comprising the steps of:

fabricating an implantable medical device having a microcontroller capable of accessing a virtual memory space, a memory system including a dynamic memory unit and a static memory unit, with each memory unit having sufficient memory to accommodate the entire virtual memory space, and a memory controller for dynamically mapping selected portions of the virtual memory space to either the dynamic memory unit or the static memory unit;

loading software for controlling the implantable medical device into the dynamic memory unit, controlling the memory controller to direct memory access commands for accessing the software to the dynamic memory and then testing the software within the implantable medical device; and

after testing of the software has been completed, storing a final version of the software in the static memory unit and controlling the memory controller to direct memory access commands for accessing the control software to the static memory.

5. The method of claim 4 wherein the step of fabricating an implantable medical device includes the step of installing a dynamic memory unit comprising a RAM, flash memory or EEPROM.

6. The method of claim 4 wherein the step of fabricating an implantable medical device includes the step of installing a static memory unit comprising a ROM.

7. The method of claim 4 further including the step, performed after testing of the software has been completed, of preprogramming the memory controller to always map certain predetermined portions of the virtual memory to the dynamic memory unit.

8. The method of claim 7 wherein the predetermined portions of the virtual memory space include portions requiring dynamic access.

9. The method of claim 8 wherein the portions requiring dynamic access include one or more of portions dedicated to storing page zero information, stack information, mailbox information, patient data and stored internal electrocardiogram (IEGM) data.

10. The method of claim 4 further including the step, performed after testing of the software has been completed, of programming the memory controller to specify, for each of a predetermined number of zones of the virtual memory, whether the memory is mapped to the dynamic memory unit or the permanent memory unit.

11. The method of claim 4 further including the step, performed after the final version of the software has been stored in the static memory unit, of transmitting an indication of a corrupted portion of memory within the dynamic memory unit or the permanent memory unit to the memory controller and re-mapping the portion of the virtual memory space previously mapped to the corrupted portion of memory to a corresponding portion of memory in the other memory unit.

12. The method of claim 4 for use within an implantable medical device selected from a group including a pacemaker and an implantable cardioverter defibrillator (ICD).

13. The method of claim 4 for use within an implantable medical device having various computing components accessing two or more virtual memory spaces.

14. A system for use in controlling the operation of an implantable medical device wherein the device has a microcontroller capable of accessing a virtual memory space, a memory system including a dynamic memory unit and a static memory unit, with each memory unit having sufficient memory to accommodate the entire virtual memory space, and a memory controller for dynamically mapping selected portions of the virtual memory space to either the dynamic memory unit or the static memory unit, the system comprising:

an external programmer operative to load the control software into the dynamic memory unit and to control the memory controller to direct memory access commands issued by the microcontroller for accessing the control software to the dynamic memory; and

a test system operative to test the operation of the control software within the implantable medical device; and

wherein the external programmer is also operative to store a final tested version of the control software in the static memory unit and to control the memory controller to direct memory access commands issued by the microcontroller for accessing the control software to the static memory.

15. A system for use in controlling the operation of an implantable medical device wherein the device has a microcontroller capable of accessing a virtual memory space, a memory system including a dynamic memory unit and a static memory unit, with each memory unit having sufficient memory to accommodate the entire virtual memory space, and a memory controller for dynamically mapping selected portions of the virtual memory space to either the dynamic memory unit or the static memory unit, the system comprising:

means for loading the control software into the dynamic memory unit;

means for controlling the memory controller to direct memory access commands for accessing the control software to the dynamic memory;

means for testing the operation of the control software within the implantable medical device;

means for storing a final tested version of the control software in the static memory unit; and

means for controlling the memory controller to direct memory access commands for accessing the control software to the static memory.