Method and apparatus for detecting insertion and removal of a memory module using standard connectors

• US 6,047,343 A
• Filed: 04/03/1999
• Issued: 04/04/2000
• Est. Priority Date: 06/05/1996
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Olarig, Sompong P.
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US09/307,254
• Time in Patent Office: 367 Days
• Field of Search: 710/101, 710/102, 710/103, 711/100, 711/115, 713/300, 714/47, 714/48, 370/257, 307/147, 361/683, 361/686, 439/377
• US Class Current: 710/302
• CPC Class Codes: G06F 13/4081 Live connection to bus, e.g. hot-plugging current or voltage limitation during live insertion H02H9/004

Abstract

A method and apparatus for detecting insertion and removal of memory modules in a computer system using standard connectors is disclosed. A memory controller includes logic to read serial presence bits from memory modules incorporating such serial presence features. In response to system software the memory controller monitors a particular slot connector where a memory module is to be inserted or removed. Changes in the serial presence bits indicate insertion or removal. Each slot connector is further connectable to a memory bus for insertion and removal of memory modules while the computer system is operational.

Claims

1. A method for detecting insertion and removal of a memory module in a connnector, the memory module having presence detection logic connectable to a common presence bus for providing presence bits, the connector having pre-determined pins connectable to the common presence bus, the method comprising:

performing a read operation on the common presence bus directed to the memory module;

determining if valid presence bits were returned in response to the read operation;

providing an insertion indication that the memory module is inserted if valid presence bits were returned in response to the read operation; and

providing a removal indication that the memory module is removed if invalid presence bits were returned in response to the read operation.

2. The method of claim 1, further comprising:

applying power to the connector before performing the read operation.

3. The method of claim 1, wherein the connector is connectable to a memory bus, the method further comprising:

connecting the memory bus to the connector in response to the insertion indication.

4. The method of claim 1, wherein the connector is connectable to a memory bus, the method comprising:

disconnecting the memory bus from the connector before performing the read operation.

5. The method of claim 4, wherein the disconnecting step includes maintaining power to the connector.

6. The method of claim 1, wherein the determining step further comprises:

determining if an exchange period has expired;

if the exchange period has expired, providing an indication to a user to complete the insertion or removal operation within a warning period; and

aborting the insertion or removal operation if the warning period has expired.

7. The method of claim 1, wherein the determining step further comprises:

determining if an exchange period has expired;

requesting a response from a user to continue waiting for the insertion or removal; and

aborting the insertion or removal operation if no response is received during a warning period.

8. A method for use with a computer system having a memory bus and a connector capable of receiving a memory module, the memory module having presence detection logic connectable to a common presence bus for providing presence bits, the connector having pre-determined pins connectable to the common presence bus, the method comprising:

performing a read operation on the common presence bus directed to the memory module;

determining if valid presence bits were returned in response to the read operation;

providing an insertion confirmation that the memory module is inserted if valid presence bits were returned in response to the read operation; and

connecting the memory bus to the connector in response to the insertion confirmation.

9. The method of claim 8, further comprising:

receiving an insertion indication that a memory module will be inserted into the connector, before performing the read operation; and

inserting the memory module after receipt of the insertion indication.

10. The method of claim 8, wherein the determining step further comprises:

determining if an exchange period has expired;

if the exchange period has expired, providing an indication to a user to complete the insertion operation within a warning period; and

aborting the insertion operation if the warning period has expired.

11. The method of claim 8, wherein the determining step further comprises:

determining if an exchange period has expired;

requesting a response from a user to continue waiting for the insertion; and

aborting the insertion operation if no response is received during a warning period.

12. A method for use with a computer system having a memory bus and a connector capable of receiving a memory module, the memory module having presence detection logic connectable to a common presence bus for providing presence bits, the connector having pre-determined pins connectable to the common presence bus, the method comprising:

disconnecting the memory bus from the connector;

performing a read operation on the common presence bus directed to the memory module after the memory bus is disconnected;

determining if valid presence bits were returned in response to the read operation; and

providing a removal indication that the memory module is removed if invalid presence bits were returned in response to the read operation.

13. The method of claim 12, further comprising:

removing the memory module after disconnecting the memory bus from the connector.

14. The method of claim 12, further comprising:

receiving an insertion indication that a memory module will be inserted into the connector;

performing a read operation on the common presence bus directed to the memory module after receipt of the insertion indication;

determining if valid presence bits were returned in response to the read operation; and

providing an insertion confirmation that the memory module is inserted if valid presence bits were returned in response to the read operation.

15. The method of claim 14, further comprising:

connecting the memory bus to the connector in response to the insertion confirmation.

16. The method of claim 14, further comprising:

inserting the memory module after receipt of the insertion indication.

17. The method of claim 12, wherein the determining step further comprises:

determining if an exchange period has expired;

if the exchange period has expired, providing an indication to a user to complete the removal operation within a warning period; and

aborting the removal operation if the warning period has expired.

18. The method of claim 12, wherein the determining step further comprises:

determining if an exchange period has expired;

requesting a response from a user to continue waiting for the removal; and

aborting the removal operation if no response is received during a warning period.

19. A computer system, comprising:

one or more memory modules, each memory module including presence detect logic for providing presence detect data;

one or more slot connectors, each for holding one memory module;

a memory bus connectable to each slot connector; and

a memory controller coupled to the memory bus and having a presence detect controller for reading presence detect data from the memory modules, the memory controller operable to cause the memory bus to be connected to a particular slot connector, and the presence detect controller operable to determine if a memory module is present in the particular slot connector by reading the presence detect data from the memory module,

wherein a memory module is not present if the presence detect data read by the presence detect controller is invalid, and

wherein a memory module is present if the presence detect data read by the presence detect controller is valid.

20. The computer system of claim 19, wherein if the memory module is present, the memory controller connects the memory bus to the particular slot connector.

21. The computer system of claim 20, further comprising:

a clock line,

wherein the memory controller connects the clock line to the particular slot connector after determining that the memory module is present.

22. The computer system of claim 19, wherein the memory controller disconnects the memory bus from the particular slot connector before determining if the memory module is present.

23. The computer system of claim 22, further comprising:

a clock line,

wherein the memory controller disconnects the clock line from the particular slot connector before determining if the memory module is present.

24. The computer system of claim 19, further comprising:

a power line,

wherein the memory controller is further operable to connect the power line to the particular slot connector before determining if the memory module is present.

25. A computer system, comprising:

one or more memory modules, each memory module including presence detect logic for providing presence detect data;

one or more slot connectors, each for holding one memory module;

a hard disk drive for storing data capable of being held in the memory modules;

a memory bus connectable to each slot connector and coupled to the hard disk drive; and

a memory controller coupled to the memory bus and having a presence detect controller for reading presence detect data from the memory modules, the memory controller operable to cause the memory bus to be connected to a particular slot connector, and the presence detect controller operable to determine if a memory module is present in the particular slot connector by reading the presence detect data from the memory module,

wherein a memory module is not present if the presence detect data read by the presence detect controller is invalid, and

wherein a memory module is present if the presence detect data read by the presence detect controller is valid.

26. The computer system of claim 25, wherein if the memory module is present, the memory controller connects the memory bus to the particular slot connector.

27. The computer system of claim 26, further comprising:

a clock line,

wherein the memory controller connects the clock line to the particular slot connector after determining that the memory module is present.

28. The computer system of claim 25, wherein the memory controller disconnects the memory bus from the particular slot connector before determining if the memory module is present.

29. The computer system of claim 28, further comprising:

a clock line,

wherein the memory controller disconnects the clock line from the particular slot connector before determining if the memory module is present.

30. The computer system of claim 25, further comprising:

a power line,

wherein the memory controller is further operable to connect the power line to the particular slot connector before determining if the memory module is present.

31. The computer system of claim 25,

wherein the memory controller further includes a timer for timing an exchange period, and

wherein if the exchange period has expired the timer causes an indication to be provided to a user to warn the user that the insertion or removal operation will be aborted after a predetermined warning period.

32. The computer system of claim 25,

wherein the memory controller further includes a timer for timing an exchange period and a warning period,

wherein if the exchange period has expired the timer causes a request to be communicated to the user requesting a response from the user to continue waiting for the insertion or removal, and

wherein the insertion or removal operation is aborted if no response is received during the warning period.

33. A computer system, comprising:

a memory module having presence detection logic connectable to a common presence bus for providing presence bits;

a connector capable of receiving the memory module, the connector being coupled to the common presence bus;

a memory bus connectable to the connector;

means for performing a read operation on the common presence bus directed to the memory module;

means for determining if valid presence bits were returned in response to the read operation;

means for providing an insertion confirmation that the memory module is inserted if valid presence bits were returned in response to the read operation; and

means for connecting the memory bus to the connector in response to the insertion confirmation.

34. The computer system of claim 33, further comprising:

means for receiving an insertion indication that a memory module will be inserted into the connector, before performing the read operation; and

means for inserting the memory module after receipt of the insertion indication.