Pseudo dual port memory

Patent metadata

Field	Value
Publication number	US-10061542-B2
Application number	US-201514855319-A
Country	US
Kind code	B2
Filing date	Sep 15, 2015
Priority date	Sep 15, 2015
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

Aspects of a memory and method for accessing the memory are disclosed. The memory includes a plurality of memory cells configured to support a read and write operation in a memory cycle in a first mode and a write only operation in the memory cycle in a second mode. The memory further includes a control circuit configured to generate a read clock for the read operation and a write clock for the write operation. The timing of the write clock is a function of the timing of the read clock in the first mode, and the timing of the memory cycle in the second mode.

First claim

What is claimed is:

1. A memory, comprising: a plurality of memory cells configured to support a read and write operation in a memory cycle in a first mode and a write only operation in the memory cycle in a second mode; and a control circuit configured to generate a read clock for the read operation and a write clock for the write operation, the read clock separate from the write clock, wherein the control circuit comprises: a read clock circuit configured to generate the read clock in response to the beginning of the memory cycle in the first mode and reset the read clock when the read operation is complete; and a write clock circuit comprising: a first circuit having an output configured to be set in response to the beginning of the memory cycle and reset when the write operation is complete; and a second circuit configured to generate the write clock when the first circuit output is set and the read clock is in a reset state in the first mode, and the beginning of the memory cycle in the second mode.

2. The memory of claim 1 , wherein the control circuit is further configured to generate the write clock by setting the write clock in response to the resetting of the read clock in the first mode.

3. The memory of claim 1 , wherein the control circuit is further configured to generate the write clock by setting the write clock in response to the beginning of the memory cycle in the second mode.

4. The memory of claim 1 , wherein the write clock circuit is further configured to reset the write clock when the write operation is complete.

5. The memory of claim 1 , wherein: the first circuit comprises a latch; and the second circuit comprises logic to gate the first circuit output and the read clock.

6. A method of accessing memory comprising a plurality of memory cells configured to support a read and write operation in a memory cycle in a first mode and a write only operation in the memory cycle in a second mode, the method comprising: generating, in the first mode, a read clock for the read operation and a write clock for the write operation, the read clock separate from the write clock, wherein the generating the write clock comprises: setting an output in response to the beginning of the memory cycle and resetting the output when the write operation is complete; and setting the write clock when the output is set and the read clock is in a reset state, in the first mode; and generating, in the second mode, the write clock for the write operation in response to the beginning of the memory cycle.

7. The method of claim 6 , wherein:
the generating the read clock, in the first mode, comprises setting the read clock in response to the beginning of the memory cycle and resetting the read clock when the read operation is complete; and
the generating the write clock, in the first mode, comprises setting the write clock in response to the resetting of the read clock and resetting the write clock when the write operation is complete.

8. The method of claim 6 , wherein the generating the write clock, in the second mode, comprises setting the write clock in response to the beginning of the memory cycle and resetting the write clock when the write operation is complete.

9. A memory comprising: a plurality of memory cells configured to support a read and write operation in a memory cycle in a first mode and a write only operation in the memory cycle in a second mode; and a control circuit configured to generate a read clock for the read operation and a write clock for the write operation, the read clock separate from the write clock, wherein the control circuit comprises: a read clock circuit configured to generate the read clock in response to the beginning of the memory cycle in the first mode and reset the read clock when the read operation is complete; and a write clock circuit configured to generate the write clock in response to: the resetting of the read clock in the first mode; and the beginning of the memory cycle in the second mode, wherein a timing of the write clock is a function of a timing of the read clock in the first mode, and wherein the write clock occurs earlier in the memory cycle in the second mode than in the first mode.

10. The memory of claim 9 , wherein the control circuit is further configured to generate the write clock by setting the write clock in response to resetting the read clock in the first mode.

11. The memory of claim 9 , wherein the control circuit is further configured to generate the write clock by setting the write clock in response to the beginning of the memory cycle in the second mode.

12. The memory of claim 9 , wherein the write clock circuit is further configured to reset the write clock when the write operation is complete.

13. The memory of claim 9 , wherein the control circuit comprises a write clock circuit comprising:
a first circuit having an output configured to be set in response to the beginning of the memory cycle and reset when the write operation is complete; and
a second circuit configured to set the write clock when the first circuit output is set and the read clock is in a reset state.

14. The memory of claim 13 , wherein:
the first circuit comprises a latch; and
the second circuit comprises logic to gate the first circuit output and the read clock.

Assignees

• Qualcomm Inc

Inventors

• Kwok Tony Chung Yiu
• Desai Nishith Nitin
• Jung Changho

Classifications

• G11C7/1075

  for multiport memories each having random access ports and serial ports, e.g. video RAM · CPC title

• G06F3/0611

  in relation to response time · CPC title

• G06F3/0659

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title

• G06F3/0683 Primary

  Plurality of storage devices · CPC title

• G11C11/419

  Read-write [R-W] circuits · CPC title