Memory device with delayed issuance of internal write command

• US 7,437,527 B2
• Filed: 04/09/2007
• Issued: 10/14/2008
• Est. Priority Date: 10/10/1997
• Status: Expired due to Fees

• Current Assignee: Rambus Inc.
• Original Assignee: Rambus Inc.
• Inventors: Hampel, Craig E., Ware, Frederick A., Davis, Paul G.
• Primary Examiner(s): BATAILLE, PIERRE MICHE
• Application Number:
  US11/733,167
• Publication Number:
  US 20070177436A1
• Time in Patent Office: 554 Days
• Field of Search: 711/167, 711/168, 711/169, 711/154, 711/105, 711/106, 711/100, 711/5, 365/201, 365/233, 365/189, 365/230.01, 365/230.03, 327/158, 327/297, 327/298, 327/299
• US Class Current: 711/167
• CPC Class Codes: G06F 13/1626 by reordering requests
• CPC Class Codes: G11C 11/4076 Timing circuits for regeneration management G11C11/406
• CPC Class Codes: G11C 2207/2218 Late write
• CPC Class Codes: G11C 2207/229 Timing of a write operation
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor
• CPC Class Codes: G11C 7/1039 using pipelining techniques, i.e. using latches between functional memory parts, e.g. row/column decoders, I/O buffers, sense amplifiers
• CPC Class Codes: G11C 7/22 Read-write [R-W] timing or clocking circuits; Read-write [R-W] control signal generators or management

Abstract

A method and apparatus for storing data in a memory device is described. The apparatus is configured to perform the following steps. The method employs a two-step technique which allows the out-of-order completion of read and write operations. When a write operation requires a resource needed for the completion of a read operation, the data being written is stored in a write data buffer in the memory device. The write data is stored in the buffer until a datapath is available to communicate the data to the memory device'"'"'s memory core. Once the resource is free (or the memory device, or its controller force the write to complete) the data is written to the memory core of the memory device using the now-free datapath.

Claims

1. A memory device comprising:

a memory core including an array of memory cells;

a first circuit to receive a write command from external control lines, wherein the write command specifies a write operation;

a second circuit coupled to the first circuit, the second circuit to store the write command for a first time period after the write command is received at the first circuit, wherein the write command initiates a write operation after the first time period has transpired; and

a third circuit to receive data from external data lines after a second time period transpires from when the write command is received at the first circuit, wherein the data is stored in the memory core in response to the write command.

2. The memory device of claim 1, wherein the second circuit comprises a first buffer stage to receive the write command from the first circuit, the first buffer stage to control storage of the write command in response to a first control signal.

3. The memory device of claim 2, wherein the second circuit comprises a second buffer stage to receive the write command from the first buffer stage, the second buffer stage to control storage of the write command in response to a second control signal.

4. The memory device of claim 1, further comprising a fourth circuit to receive mask information from external mask lines, the mask information indicating whether to mask portions of the data to be stored in the memory core.

5. The memory device of claim 4, further comprising a fifth circuit to receive the data from the third circuit, to store the received data, and to present the received data to the memory core.

6. The memory device of claim 5, further comprising a sixth circuit to receive the mask information from the fourth circuit, to store the mask information, and to provide the mask information to the memory core.

7. The memory device of claim 1, wherein the memory cells are dynamic random access memory cells.

8. A memory device comprising:

a memory core including an array of dynamic random access memory cells;

a transport block to receive a write command from external control lines, wherein the write command specifies a write operation;

a write control buffer coupled to the transport block, the write control buffer to store the write command for a first time period after the write command is received at the transport block, wherein the write command initiates the write operation after the first time period has transpired; and

a data buffer to receive data from external data lines after a second time period transpires from when the write command is received at the transport block, wherein the data is stored in the memory core in response to the write command.

9. The memory device of claim 8, further comprising a mask buffer to receive mask information from external mask lines, the mask information indicating whether to mask portions of the data to be stored in the memory core.

10. The memory device of claim 8, wherein the memory cells are dynamic random access memory cells.

11. A memory device comprising:

a memory core including an array of memory cells;

a first circuit to receive a write command from external control lines, wherein the write command specifies a write operation;

a second circuit coupled to the first circuit, the second circuit to store the write command for a first time period after the write command is received at the first circuit, wherein the write command initiates a write operation after the first time period has transpired;

a third circuit to receive data from external data lines, wherein the data is stored in the memory core in response to the write command; and

a fourth circuit to receive mask information from external mask lines, the mask information indicating whether to mask portions of the data to be stored in the memory core.

12. The memory device of claim 11, further comprising a fifth circuit to receive the data from the third circuit, to store the received data, and to present the received data to the memory core.

13. The memory device of claim 12, further comprising a sixth circuit to receive the mask information from the fourth circuit, to store the mask information, and to provide the mask information to the memory core.

14. The memory device of claim 11, wherein the memory cells are dynamic random access memory cells.

15. A memory device comprising:

a memory core including an array of dynamic random access memory cells;

a transport block to receive a write command from external control lines, wherein the write command specifies a write operation;

a write control buffer coupled to the transport block, the write control buffer to store the write command for a first time period after the write command is received at the transport block, wherein the write command initiates the write operation after the first time period has transpired;

a data buffer to receive data from external data lines, wherein the data is stored in the memory core in response to the write command; and

a write mask buffer to receive mask information from external mask lines, the mask information indicating whether to mask portions of the data to be stored in the memory core.

16. The memory device of claim 15, wherein the write control buffer comprises a first write control buffer stage and a second write control buffer stage to receive the write command from the first buffer stage in response to a control signal.

17. The memory device of claim 15, wherein the data buffer comprises a first data buffer stage to receive the data from the external data lines and a second data buffer stage to receive the data from the first data buffer stage and to provide the data to the memory core.

18. The memory device of claim 17, wherein the write mask buffer comprises a first mask buffer stage to receive the mask information from the external data lines and a second mask buffer stage to receive the mask information from the first mask buffer stage and to provide the data to the memory core.

19. A method of operation in a single chip memory device, the method comprising:

receiving a write command from control signal lines that are external to the memory device, wherein the write command specifies a write operation;

storing the write command for a first time period after receiving the write command;

receiving, after a second time period has transpired from receiving the write command, data from data signal lines that are external to the memory device;

after the first time period, initiating the write operation in response to the write command; and

writing the data to a memory core of the memory device during the write operation.

20. The method of claim 19, further comprising receiving mask information that indicates whether to mask portions of the data while writing the data to the memory core during the write operation.

21. The method of claim 19, further comprising:

holding the data in a write buffer after receiving the data; and

receiving a retire command that indicates releasing the data from the write buffer for the writing to the memory core during the write operation.

22. The method of claim 19, wherein storing the write command comprises buffering the write command through a plurality of buffer stages during the first time period.

23. The method of claim 19, further comprising:

receiving a read command that specifies a read operation;

applying the read command to the memory core to service the read operation; and

outputting data corresponding to the read command, wherein the time period from receiving the read command to outputting the read data is a channel turnaround time less than the first time period.

24. The method of claim 19, further comprising,

after receiving the data, storing the data in a write buffer until the first time period expires;

and

after the first time period transpires, releasing the data from the write buffer for the writing to the memory core during the write operation.

25. A method of operating a memory device having a memory core, the method comprising:

providing a write command that specifies a write operation to the memory device, wherein, after receiving the write command the memory device stores the write command for a first time period before initiating the write operation in response to the write command;

providing data to the memory device after a second time period has transpired after providing the write command, wherein the memory device stores the data in the memory core during the write operation.

26. The method of claim 25, further providing mask information to the memory device, the mask information indicating whether to mask portions of the data while writing the data to the memory core during the write operation.

27. The method of claim 26, wherein the mask information is provided to the memory device before the data is provided to the memory device.

28. The method of claim 25, including storing the data in a write buffer of the memory device after receiving the data, and further comprising providing a retire command to the memory device, wherein the retire command indicates releasing the data from a write buffer for the writing to the memory core during the write operation.

29. The method of claim 25, further comprising:

providing a read command to the memory device, wherein the read command specifies a read operation; and

the memory device outputting data corresponding to the read command, wherein the time period from receiving the read command to outputting the read data is a channel turnaround time less than the first time period.