Memory circuit with integrated processor

• US 10,324,870 B2
• Filed: 02/12/2016
• Issued: 06/18/2019
• Est. Priority Date: 02/18/2015
• Status: Active Grant

• Current Assignee: Upmem SAS
• Original Assignee: Upmem SAS
• Inventors: Devaux, Fabrice, Roy, Jean-Francois
• Primary Examiner(s): Shyu, Jing-Yih
• Application Number:
  US15/551,418
• Publication Number:
  US 20180039586A1
• Time in Patent Office: 1,222 Days
• CPC Class Codes: G06F 13/1636 using refresh
• CPC Class Codes: G06F 13/1673 using buffers

Abstract

A memory circuit having: a memory array including one or more memory banks; a first processor; and a processor control interface for receiving data processing commands directed to the first processor from a central processor, the processor control interface being adapted to indicate to the central processor when the first processor has finished accessing one or more of the memory banks of the memory array, these memory banks becoming accessible to the central processor.

Claims

1. A memory circuit comprising:

a memory array comprising one or more memory banks;

a first processor; and

a processor control interface for receiving data processing

commands directed to the first processor from a central processor, wherein the processor control interface includes a set of control registers accessible within an address space of the memory circuit and wherein the processor control interface is configured to indicate through the control registers to the central processor when the first processor has finished accessing one or more of the memory banks of the memory array, these memory banks becoming accessible to the central processor, and wherein the processor control interface does not comprise any dedicated control line for collision arbitration between the first processor and the central processor;

wherein the memory circuit is a dynamic random access memory circuit further comprising a refresh control circuit configured;

to receive, from the central processor, refresh transactions for performing data refresh operations in at least one memory bank of the memory array;

to determine whether the at least one memory bank is being accessed by the first processor, and if so, to delay a start time of the data refresh operation.

2. The memory circuit of claim 1, wherein the refresh control circuit comprises a refresh pending register, and wherein delaying a start time of the data refresh operation comprising indicating in the refresh pending register that the refresh operation is pending.

3. The memory circuit of claim 1, wherein the address space of the memory circuit comprises one or more addresses permanently associated with the set of control registers.

4. The memory circuit of claim 1, wherein the address space of the memory circuit comprises one or more addresses associated with the set of control registers, and wherein said one or more addresses are configured to be transformed to addresses of the memory array upon assertion of a register deactivation control signal.

5. The memory circuit of claim 1, wherein the processor control interface is configured to receive an activation signal from the central processor for rendering the set of control registers accessible within the address space of the memory circuit.

6. The memory circuit of claim 5, wherein the activation signal is provided via an address bus, and is detectable by the processor control interface.

7. The memory circuit of claim 6, wherein the memory access sequence for rendering the set of control registers accessible is a burst access sequence in which not all of the words are written.

8. The memory circuit of claim 6, wherein the memory access sequence for rendering the set of control registers accessible is a plurality of memory accesses to memory cells within a memory zone in one of said memory banks within a first time period.

9. The memory circuit of claim 6, wherein the memory circuit is configured to detect the memory access sequence based on one or more of:

a time period in which the memory access sequence is received; and

a time duration of the memory access sequence.

10. A system comprising:

a plurality of memory circuits of claim 1; and

a central processor coupled to each of the memory circuits via a common N-bit data bus, each memory circuit comprising an N-bit bus interface coupled to the N-bit data bus.

11. A method of accessing a memory circuit comprising

a memory array having one or more memory banks;

a first processor; and

a processor control interface comprising a set of control registers accessible within an address space of the memory circuit, the method comprising;

receiving, by the processor control interface, data processing commands directed to the first processor from a central processor;

indicating, by one of the control registers of the processor control interface (904) to the central processor, and without using any dedicated control line for collision arbitration between the first processor and the central processor, when the first processor has finished accessing one or more of the memory banks of the memory array, these memory banks becoming accessible to the central processor;

wherein the memory circuit is a dynamic random access memory circuit, the method further comprising;

receiving, by a refresh control circuit, a refresh transaction for performing a data refresh operation in a memory bank of the memory array;

determining, by the refresh control circuit, whether the memory bank is being accessed by the first processor, and if so, delaying a start time of the data refresh operation.

12. The method of claim 11, further comprising:

receiving by the processor control interface an activation signal from the central processor for rendering the set of control registers accessible within an address space of the memory circuit.