Individually addressing memory devices disconnected from a data bus
Memory devices and methods for operating the same are provided. A memory device can include at least one command contact and at least one data contact. The memory device can be configured to detect a condition in which the at least one command contact is connected to a controller and the at least one data contact is disconnected from the controller, and to enter, based at least in part on detecting the condition, a first operating mode with a lower nominal power rating than a second operating mode. Memory modules including one or more such memory devices can be provided, and memory systems including controllers and such memory modules can also be provided.
1. A memory module, comprising:
a plurality of memories, each of the plurality of memories including:
at least one command contact, and
at least one data contact,
wherein at least one of the plurality of memories is configured to:
detect a condition in which the at least one command contact thereof is connected to a controller and the at least one data contact thereof is disconnected from the controller, and
perform an action based at least in part on detecting the condition.
2. The memory module of claim 1 , wherein the action includes changing an on-die termination level.
3. The memory module of claim 1 , wherein the action includes entering a mode in which signals received at the at least one command contact are ignored.
4. The memory module of claim 1 , wherein the condition is a first condition and the action is a first action, and wherein the at least one of the plurality of memories is configured to perform a second action based at least in part upon detecting a second condition in which the data contact is connected to the controller.
5. The memory module of claim 1 , further comprising:
a connector having:
a plurality of connector data contacts, each of the plurality of connector contacts coupled to a corresponding one of the at least one data contacts of one of the plurality of memories, and
a plurality of connector command contacts, each of the plurality of connector command contacts coupled to a corresponding one or more of the at least one command contacts of the plurality of memories.
6. The memory module of claim 5 , wherein the connector is a DIMM slot.
7. The memory module of claim 1 , wherein the at least one command contact of each of the plurality of memories is coupled to a common command/address bus of the memory module.
8. The memory module of claim 1 , wherein the at least one of the plurality of memories of the at least one memory module is configured to detect the condition by detecting a command signal at the at least one command contact and determining that the at least one data contact is grounded.
9. The memory module of claim 1 , wherein the command signal comprises a reset signal.
10. The memory module of claim 1 , wherein the at least one command contact of each of the plurality of memories includes a first strobe contact and a second strobe contact, and wherein the at least one of the plurality of memories is configured to detect the condition based at least in part on determining that the first and second strobe contacts are driven to opposing high and low levels.
11. The memory module of claim 10 , wherein the first strobe contact and the second strobe contact are coupled to a first-in first-out (FIFO) counter, and wherein determining that the first and second strobe contacts are driven to opposing high and low levels includes determining that the FIFO counter is below a predetermined threshold.
12. The memory module of claim 1 , wherein the at least one memory module is a (dual inline memory module) DIMM.
13. A memory system, comprising:
a controller; and
at least one memory module coupled to the controller, the at least one memory module including a plurality of memories, each of the plurality of memories including:
at least one command contact, and
at least one data contact,
wherein at least one of the plurality of memories is configured to:
detect a condition in which the at least one command contact thereof is connected to the controller and the at least one data contact thereof is disconnected from the controller, and
perform an action based at least in part on detecting the condition.
14. The memory system of claim 13 , wherein the action includes changing an on-die termination level.
15. The memory system of claim 13 , wherein the action includes entering a mode in which signals received at the at least one command contact are ignored.
16. The memory system of claim 13 , wherein the condition is a first condition and the action is a first action, and wherein the at least one of the plurality of memories is configured to perform a second action based at least in part upon detecting a second condition in which the data contact is connected to the controller.
17. The memory system of claim 13 , wherein the controller includes a plurality of controller data contacts insufficient in number to be uniquely coupled to the at least one data contact of each of the plurality of memories of the at least one memory module.
18. A method of operating a memory module including a plurality of memories, the method comprising:
detecting a condition in which at least one command contact of a first memory of the plurality of memories is connected to a controller from which at least one data contact of the first memory is disconnected; and
based at least in part on detecting the condition, performing an action with the first memory.
19. The method of claim 18 , wherein the action includes changing an on-die termination level of the first memory.
20. The method of claim 18 , wherein the action includes entering the first memory into a mode in which signals received at the at least one command contact are ignored.