Solid state memory system including plural memory chips and a serialized bus

• US 5,430,859 A
• Filed: 07/26/1991
• Issued: 07/04/1995
• Est. Priority Date: 07/26/1991
• Status: Expired due to Term

• Current Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Original Assignee: SunDisk Corporation (Seagate Technology Holdings Plc)
• Inventors: Stai, Jeffrey D., Gupta, Anil, Mehrotra, Sanjay, Norman, Robert D., Lofgren, Karl M. J.
• Primary Examiner(s): Gossage, Glenn
• Application Number:
  US07/736,733
• Time in Patent Office: 1,439 Days
• Field of Search: 395/425, 395/500, 395/325, 365/230.03, 365/52, 365/900, 365/63
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0676 the address being position dependent
• CPC Class Codes: G06F 13/1668 Details of memory controller
• CPC Class Codes: G06F 13/4243 with synchronous protocol
• CPC Class Codes: G06F 3/0613 in relation to throughput
• 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 5/00 Details of stores covered by group G11C11/00
• CPC Class Codes: G11C 5/04 Supports for storage elements , e.g. memory modules; Mounting or fixing of storage elements on such supports
• CPC Class Codes: G11C 5/066 Means for reducing external access-lines for a semiconductor memory clip, e.g. by multiplexing at least address and data signals
• CPC Class Codes: G11C 8/12 Group selection circuits, e.g. for memory block selection, chip selection, array selection
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A memory system includes an array of solid-state memory devices which are in communication with and under the control of a controller module via a device bus with very few lines. This forms an integrated-circuit mass storage system which is contemplated to replace a mass storage system such as a disk drive memory in a computer system. Command, address and data information are serialized into component strings and multiplexed before being transferred between the controller module and the array of memory devices. The serialized information is accompanied by a control signal to help sort out the multiplexed components. Each memory device in the array is mounted on a multi-bit and assigned an array address. A memory device is selected by an appropriate address broadcast over the device bus, without requiring the usual dedicated select signal. A particular multi-bit mount configuration is used to unconditionally select the device mounted thereon. A predefined address broadcast over the device bus deselects all previously selected memory devices. Read performance is enhanced by a read streaming technique in which while a current chunk of data is being serialized and shifted out of the memory devices to the controller module, the controller module is also setting up the address for the next chunk of data to begin to address the memory system.

Claims

1. A mass storage system for use with a computer system, comprising:

a plurality of solid-state memory chips, each having a large number of memory cells therein;

a memory chip controller coupled to the computer system for controlling said plurality of memory chips;

a device bus for connecting said memory chip controller to each of said plurality of solid-state memory chips, said device bus carrying serialized address, data and command information, thereby substantially reducing the number of connections between said memory chip controller and each of said plurality of memory chips;

one or more backplanes each containing a plurality of mounts, each of said plurality of mounts for receiving one of said plurality of memory chips;

said device bus being coupled to each of the plurality of mounts for connection to the memory chip thereon;

a set of device-select pinouts on each of said memory chips; and

a set of pads on each of said mounts for connection to the set of device select pinouts of a memory chip mounted thereon, each set of pads having a predetermined configuration of grounded pads to define a mount address and therefore a unique array address for each of said memory chips mounted on said one or more backplanes.

2. A mass storage system as in claim 1, wherein the memory chips are flash EEPROM devices.

3. A mass storage system as in claim 1, each device select circuit further including:

a device deselect circuit for disabling a corresponding memory chip whenever an array address received from the device bus coincides with a predetermined address.

4. A mass storage system as in claim 3, wherein the memory chips are flash EEPROM devices.

5. A mass storage system as in claim 1, each of said memory chips further including:

a device select circuit for enabling a corresponding memory chip whenever an array address received from the device bus coincides with the array address defined by the predetermined configuration of grounded pads on the mount of the corresponding memory chip.

6. A mass storage system as in claim 5, wherein the memory chips are flash EEPROM devices.

7. A mass storage system as in claim 5, each device select circuit further including:

means responsive to an asserted chip-select signal and a clock signal from the device bus for converting a serialized array address from the device bus to a corresponding parallel array address; and

means for asserting a memory chip-select signal whenever a match occurs between the corresponding parallel array address and the array address defined by the predetermined configuration of grounded

8. A mass storage system as in claim 7, wherein the memory chips are flash EEPROM devices.

9. A mass storage system as in claim 5, each device select circuit further including:

a master select circuit for enabling a corresponding memory chip whenever the corresponding set of pads are configured with a predetermined, master select grounding configuration.

10. A mass storage system as in claim 9, wherein the memory chips are flash EEPROM devices.

11. A mass storage system as in claim 9, wherein each memory chip is enabled by a corresponding master select circuit and a dedicated chip select signal.

12. A mass storage system as in claim 11, wherein the memory chips are flash EEPROM devices.

13. A mass storage system for use with a computer system, comprising:

a plurality of solid-state memory chips, each having a large number of memory cells therein;

a memory chip controller coupled to the computer system for controlling said plurality of memory chips;

a device bus for connecting said memory chip controller to each of said plurality of solid-state memory chips, said device bus carrying serialized address, data and command information, thereby substantially reducing the number of connections between said memory chip controller and each of said plurality of memory chips;

one or more memory submodules each containing a plurality of memory-device mounts, each of said plurality of memory-device mounts for receiving one of said plurality of memory chips;

one or more backplanes each containing a plurality of submodule mounts for receiving one of said one or more memory submodules;

said device bus being coupled to each memory submodule for connection to each memory-device mount and therefore to each memory chip thereon;

a set of device-select pinouts on each of said memory chips;

a set of pads on each of said memory-device mounts for connection to the set of device-select pinouts of a memory chip mounted thereon, each set of pads being partitioned into a first and second subset of pads;

each first subset of pads providing a first group of grounded pads configurations to define unique addresses for all memory-device mounts and therefore addresses for corresponding memory chips mounted on each memory submodule; and

each second subset of pads being connected to pads on a corresponding submodule mount and providing a second group of grounded pads configurations to define unique addresses for all submodule mounts and therefore addresses for corresponding memory submodules mounted on said one or more backplanes.

14. A mass storage system as in claim 13, wherein the memory chips are flash EEPROM devices.

15. A mass storage system as in claim 13, each device select circuit further including:

a device deselect circuit for disabling a corresponding memory chip whenever an array address received from the device bus coincides with a predetermined address.

16. A mass storage system as in claim 15, wherein the memory chips are flash EEPROM devices.

17. A mass storage system as in claim 13, each of said memory chips further including:

a device select circuit for enabling a corresponding memory chip whenever an array address received from the device bus coincides with the address defined by the configuration of grounded pads on the mount of the corresponding memory chip.

18. A mass storage system as in claim 17, wherein the memory chips are flash EEPROM devices.

19. A mass storage system as in claim 17, each device select circuit further including:

means responsive to an asserted chip-select signal and a clock signal from the device bus for converting a serialized array address from the device bus to a corresponding parallel array address; and

means for asserting a memory chip-select signal whenever a match occurs between the corresponding parallel array address and the address defined by the configuration of grounded pads on the mount of the corresponding memory chip.

20. A mass storage system as in claim 19, wherein the memory chips are flash EEPROM devices.

21. A mass storage system as in claim 17, each device select circuit further including:

a master select circuit for enabling a corresponding memory chip whenever the corresponding set of pads are configured with a predetermined, master select grounding configuration.

22. A mass storage system as in claim 21, wherein the memory chips are flash EEPROM devices.

23. A mass storage system as in claim 21, wherein each memory chip is enabled by a corresponding master select circuit and a dedicated chip select signal.

24. A mass storage system as in claim 23, wherein the memory chips are flash EEPROM devices.

25. A mass storage system for use with a computer systems comprising:

a plurality of solid-state memory chips, each having a large number of memory cells therein;

a memory chip controller coupled to the computer system for controlling said plurality of memory chips;

a device bus for connecting said memory chip controller to each of said plurality of solid-state memory chips, said device bus carrying serialized address, data and command information, thereby substantially reducing the number of connections between said memory chip controller and each of said plurality of memory chips;

each solid-state memory device chip further including;

a serial protocol logic for controlling a protocol of the serialized address, data and command information carried on the device bus, said serial protocol logic comprising;

first routing and converting means for routing and converting serialized addresses from the device bus to a parallel address bus;

second routing and converting means for routing and converting serialized data from the device bus to a parallel data bus;

third routing and converting means for routing and converting serialized command codes from the device bus to a plurality of parallel command lines;

a pointer shift register means for capturing a code from the device bus;

a pointer decode means for selectively enabling one of the first, second and third routing and converting means; and

a serial protocol control signal from the device bus for enabling said pointer shift register means for capturing the code from the device bus while disabling said first, second and third routing and converting means, and for disabling said pointer shift register means after the code has been captured and enabling a selected one of said first, second and third routing and converting means.

26. A mass storage system as in claim 25, wherein the memory chips are flash EEPROM devices.