Controller to execute error correcting code algorithms and manage NAND memories

• US 8,806,293 B2
• Filed: 10/09/2008
• Issued: 08/12/2014
• Est. Priority Date: 10/09/2008
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Tiziani, Federico, Campardo, Giovanni, Iaculo, Massimo, Caraccio, Danilo, Vitale, Ornella, Pollio, Antonino, Giaccio, Claudio, Scognamiglio, Manuela
• Primary Examiner(s): ABRAHAM, ESAW T
• Application Number:
  US13/122,909
• Publication Number:
  US 20110307762A1
• Time in Patent Office: 2,133 Days
• Field of Search: 714/763, 365/185.02, 365/185.09, 365/185.33
• US Class Current: 714/763
• CPC Class Codes: G06F 1/3275 Power saving in memory, e.g. RAM, cache
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: G06F 11/1044 with specific ECC/EDC distribution
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G06F 11/1072 in multilevel memories
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 13/1668 Details of memory controller
• CPC Class Codes: G06F 3/0625 Power saving in storage systems
• CPC Class Codes: G06F 3/0634 by changing the state or mode of one or more devices
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A single virtualized ECC NAND controller executes an ECC algorithm and manages a stack of NAND flash memories. The virtualized ECC NAND controller allows the host processor to drive the stack of flash memory devices as a single NAND chip while the controller redirects the data to the selected NAND memory device in the stack.

Claims

1. A storage system to couple to a host, the storage system comprising:

a plurality of NAND memory devices, the plurality of NAND memory devices not internally implementing an error correcting code (ECC) algorithm; and

a controller external to the plurality of NAND memory devices, the controller to export to the host a virtualized address space to allow the host to drive the storage system as a single NAND memory device even though the storage system includes a plurality of NAND memory devices, the controller further to provide a single virtualized ECC algorithm for each of the plurality of NAND memory devices.

2. The storage system of claim 1, wherein the controller implements an Error Correcting Code (ECC) algorithm and not data management algorithms of wear leveling and bad block management.

3. The storage system of claim 2, wherein the controller includes a protocol interface circuit with a buffer to reduce latency introduced by calculations of the ECC algorithm.

4. The storage system of claim 3, wherein the protocol interface circuit manages a NAND Ready/Busy signal to the host processor to account for ECC algorithm latency.

5. The storage system of claim 1, wherein the controller manages a page size of the each of the plurality of NAND memory devices that are different from a page size of the host.

6. The storage system of claim 1, wherein the controller adapts commands issued by the host that are not supported by the plurality of NAND memory devices.

7. The storage system of claim 1, wherein the controller is a non-volatile memory device configured to redirect data received from the host processor to a selected one or more of the plurality of NAND memory devices.

8. A controller to interface with a plurality of NAND memory devices in a storage system, the controller comprising:

a protocol interface circuit to exchange signals with a host processor;

an Error Correcting Code (ECC) engine to implement an ECC algorithm; and

a NAND interface to manage the plurality of NAND memory devices, the NAND interface configured to emulate commands issued by the host processor that are not supported by the plurality of NAND memory devices, the NAND interface further configured to provide power to a select one of the plurality of NAND memory devices at a time to conserve overall power consumption of the storage system.

9. The controller of claim 8, wherein the controller is a bridge from a host NAND interface to the plurality of NAND memory devices that is to select an ECC algorithm to the host processor for the plurality of NAND memory devices provided in the storage system.

10. The controller of claim 8, wherein the controller manages a page size from the host processor that is different from a page size of the plurality of NAND memory devices.

11. The controller of claim 8, wherein the controller presents a single NAND interface to the host processor that removes a restriction on a number of usable flashes in each of the plurality of NAND memory devices due to available address input cycles.

12. The controller of claim 8, wherein the controller includes a protocol interface circuit with a buffer to transfer data to the host processor having buffering capabilities to read a second page of data for parallelizing ECC algorithm execution in a sequential read operation.

13. The controller of claim 12, wherein the protocol interface circuit manages a NAND Ready/Busy signal to the host processor to account for ECC algorithm latency.

14. A method of managing a stack of NAND memory devices that do not internally implement an Error Correcting Code (ECC) algorithm, the method comprising:

using a protocol interface block of a controller device to exchange signals with a host processor to allow the host processor to communicate with a large error free address space;

implementing a single virtualized ECC algorithm by an ECC engine block embedded in the controller device; and

re-elaborating both commands and addresses received from the host processor by a NAND interface block embedded in the controller device to manage data transfers to the stack of NAND memory devices.

15. The method of claim 14, further including interpreting commands received from the host processor by the protocol interface block to direct the storage of data from the host processor.

16. The method of claim 14, further including loading a buffer in the protocol interface block having buffering capabilities to read a second page of data for parallelizing ECC algorithm execution in a sequential read operation.

17. A wireless communication system including multiple NAND memory devices, the wireless communication system comprising:

a transceiver;

a processor having first and second processor cores, the processor being coupled to the transceiver; and

an Error Correcting Code (ECC) controller having an embedded NAND interface block to receive commands and addresses and exchange signals with the processor, an ECC engine to implement an ECC algorithm, and a NAND interface circuit to re-elaborate both commands and addresses received from the host processor to direct data transfers with the multiple NAND memory devices, the multiple NAND memory devices not internally implementing an ECC algorithm.

18. The wireless communication system of claim 17 wherein the ECC controller further includes a protocol interface circuit having a buffer to reduce latency introduced by calculations of the ECC algorithm.

19. The wireless communication system of claim 17, wherein the ECC controller allows the processor to drive the multiple NAND memory devices as a single NAND memory device while the ECC controller redirects data received from the processor to a selected NAND memory device.

20. The wireless communication system of claim 17 wherein the ECC controller allows the processor to manage a page size that differs from a page size of the multiple NAND memory devices.