Simultaneous pipelined read with multiple level cache for improved system performance using flash technology

• US 7,877,566 B2
• Filed: 01/25/2005
• Issued: 01/25/2011
• Est. Priority Date: 01/25/2005
• Status: Expired due to Fees

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Adusumilli, Vijaya P.
• Primary Examiner(s): RIGOL, YAIMA
• Application Number:
  US11/043,277
• Publication Number:
  US 20060168418A1
• Time in Patent Office: 2,191 Days
• Field of Search: 711167-169, 711102- 3, 711117-140, 711/142, 711/115, 711/102, 711/103, 365/189.05, 365/200, 365/222, 365/230.03
• US Class Current: 711/169
• CPC Class Codes: G06F 12/0855 Overlapped cache accessing, e.g. pipeline G06F12/0846 takes precedence
• CPC Class Codes: G06F 12/0897 with two or more cache hierarchy levels with multilevel cache hierarchies G06F12/0811
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G11C 16/26 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 2207/2245 Memory devices with an internal cache buffer
• 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 7/1051 Data output circuits, e.g. read-out amplifiers, data output buffers, data output registers, data output level conversion circuits
• CPC Class Codes: G11C 7/106 Data output latches

Abstract

A read command protocol and a method of accessing a nonvolatile memory device having an internal cache memory. A memory device configured to accept a first and second read command, outputting a first requested data while simultaneously reading a second requested data. In addition, the memory device may be configured to send or receive a confirmation indicator.

Claims

1. A command protocol method for a nonvolatile memory device, the command protocol method comprising:

sending a first read command for one or more first pages of data to said nonvolatile memory device;

sending a first data address to said nonvolatile memory device, said nonvolatile memory device reading one or more first pages of data in accord with said first read command beginning at said first data address and loading said one or more first pages of data one page at a time from a memory array within said nonvolatile memory device into a data register that transfers the one or more first pages of data into a first level of a cache memory of said nonvolatile memory device with multiple page capacity, said cache memory having multiple levels within said nonvolatile memory device, said cache memory being separate from said data register, said data register having a capacity to store a single page of data, said data register and said cache memory controlled by control logic within said nonvolatile memory device such that said control logic controls the reading;

transferring the one or more first pages of data from the first level of the cache memory to a second level of the cache memory;

sending a second read command for one or more second pages of data to said nonvolatile memory device before receiving an entirety of the first pages of data located beginning at said first data address; and

sending a second data address to said nonvolatile memory device before receiving the entirety of first pages of data located beginning at said first data address, the nonvolatile memory device reading one or more second pages of data in accord with the second read command beginning at said second data address and loading the one or more second pages of data one page at a time via the data register into said first level of said cache memory while simultaneously outputting the one or more first pages of data from the second level of said cache memory to an input-output circuit within said nonvolatile memory device.

2. The command protocol method of claim 1 wherein the command protocol is executed by a microprocessor coupled to said nonvolatile memory device.

3. The command protocol method of claim 1 wherein a first confirmation indicator is sent to said nonvolatile memory device after sending said first read command and sending said first data address.

4. The command protocol method of claim 1 wherein a first confirmation indicator is sent from said nonvolatile memory device in response to receiving said first read command and said first data address.

5. The command protocol method of claim 1 wherein a second confirmation indicator is sent to said nonvolatile memory device after sending said second read command and sending said second data address.

6. The command protocol method of claim 1 wherein a second confirmation indicator is sent from said nonvolatile memory device in response to receiving said second read command and said second data address.

7. The command protocol method of claim 1 wherein portions of said entirety of data located at said first data address is being received while said nonvolatile memory device is simultaneously reading data located at said second data address.

8. The method of claim 1, wherein the method includes transferring said one or more first pages of data loaded into a plurality of bit arrays of said first level of said cache memory to a plurality of bit arrays of said second level of said cache memory.

9. A method of reading from a nonvolatile memory device, the method comprising:

receiving, at the nonvolatile memory device, a first read command and a first memory address from a microprocessor coupled to said nonvolatile memory device;

setting a read verification indicator in response to said first read command;

reading a first plurality of data pages from a memory array one page at a time into a data register, said data register located within said nonvolatile memory device, said data register having a capacity to store a single page of data, said nonvolatile memory device having a cache memory within said nonvolatile memory device, said cache memory being separate from said data register, said data register and cache memory controlled by control logic within said nonvolatile memory device such that said control logic controls the reading;

copying said first plurality of data pages from said data register, as each page is read from said memory array, into a first level cache of said cache memory within said nonvolatile memory device, said cache memory having multiple page capacity and having multiple level caches within said nonvolatile memory device;

transferring the first plurality of data pages from the first level cache of said cache memory to a second level cache of said cache memory;

receiving, at the nonvolatile memory device, a second read command and second memory address from the microprocessor;

setting said read verification indicator in response to said second read command; and

outputting said first plurality of data pages from the second level cache of said cache memory to an input-output circuit within said nonvolatile memory device to the microprocessor while simultaneously reading a second plurality of data pages from said memory array one page at a time into said data register and copying said second plurality of data pages into said first level cache as each page is read from said memory array.

10. The method of claim 9 wherein said first level cache and said second level cache both include multiple page capacity.

11. The method of claim 9 wherein said first plurality of data pages are read from said memory array and copied to said first level cache, then subsequently copied to said second level cache after checking availability of said second level cache.

12. The method of claim 9 wherein said read verification indicator is a read verification line driven by said nonvolatile memory device.

13. The method of claim 9 wherein a third read command and third memory address are received, said read verification indicator is inverted, and said second plurality of data pages is outputted while simultaneously reading and storing a third plurality of data pages from said memory array.

14. The method of claim 9 further comprising:

receiving a third read command and third memory address;

setting said read verification indicator in response to said third read command; and

outputting said second plurality of data pages while simultaneously reading and storing a third plurality of data pages from said memory array.

15. The method of claim 9, wherein copying said first plurality of data pages from said data register into said first level cache includes copying said first plurality of data pages from said data register into said first level cache with said first level cache arranged as a plurality of first level bit arrays.

16. The method of claim 15, wherein copying said first plurality of data pages from said data register into said first level cache includes selecting one of said first level bit arrays and copying a portion of first plurality of data pages into said selected first level bit array with other first level bit arrays not selected to receive data while copying said portion into said selected first level bit array.

17. A method of reading from a nonvolatile memory device, the method comprising:

reading at least one page of data from a nonvolatile memory array automatically one page at a time into a page register, the page register within said nonvolatile memory device, said nonvolatile memory device having a multi-page cache memory within said nonvolatile memory device, said multi-page cache memory being separate from said page register, said page register having a capacity to store a single page of data, said page register and multi-page cache memory controlled by control logic within said nonvolatile memory device such that said control logic controls the reading;

copying said at least one page of data one page at a time from said page register to a first level cache of said multi-page cache memory of said nonvolatile memory device;

transferring the at least one page data from said first level cache of said multi-page ache memory to a second level cache of said multi-page cache memory;

copying a plurality of bits from said at least one page of data between the second level cache of said multi-page cache memory and an input-output circuit; and

outputting, to an input-output circuit of said nonvolatile memory device, at least one bit of said plurality of bits from said at least one page of data and simultaneously reading at least one other page of data from said nonvolatile memory array automatically via said page register, into said first level cache of said multi-page cache memory.

18. The method of claim 17 wherein said first level cache and said second level cache both include multiple bit arrays.

19. The method of claim 17 wherein said at least one page of data are read from said memory array and copied to said first level cache, then subsequently copied to said second level cache after checking availability of said second level cache.

20. The method of claim 17 wherein reading at least one page of data automatically occurs during a boot-up process or during a reset process.

21. The method of claim 17 wherein said one page of data is stored at a predetermined memory address.

22. The method of claim 21 wherein a second predetermined memory address is used to simultaneously read said at least one other page of data.

23. The method of claim 21 wherein said predetermined memory address is incremented to simultaneously read said at least one other page of data.

24. The method of claim 17 wherein said input-output circuit is coupled to a volatile memory device and said plurality of bits are sent to said volatile memory device.

25. The method of claim 24 wherein said volatile memory device provides a ready indicator before said plurality of bits are sent to said volatile memory device.

26. The method of claim 17 wherein said input-output circuit is coupled to a microprocessor and said plurality of bits are sent to said microprocessor.

27. The method of claim 26 wherein said microprocessor provides a ready indicator before said plurality of bits are sent to said microprocessor.

28. The method of claim 17, wherein copying said at least one page of data from said page register to said first level cache includes copying said at least one page of data from said page register to said first level cache with said first level cache arranged as a plurality of first level bit arrays.

29. The method of claim 28, wherein copying said at least one page of data from said page register to said first level cache includes selecting one of said first level bit arrays and copying a portion of said at least one page of data into said selected first level bit array with other first level bit arrays not selected to receive data while copying said portion into said selected first level bit array.