Serial flash semiconductor memory

• US 20060067123A1
• Filed: 03/11/2005
• Published: 03/30/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Winbond Electronics Corporation
• Original Assignee: NexFlash Technologies, Inc. (Winbond Electronics Corporation)
• Inventors: Jigour, Robin J., Park, Eungjoon, Lee, Jong Seuk, Park, Joo Weon
• Granted Patent: US 7,558,900 B2
• Time in Patent Office: Days
• US Class Current: 365/185.50
• CPC Class Codes: G11C 16/26 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 2207/108 Wide data ports
• CPC Class Codes: G11C 2216/30 Reduction of number of input/output pins by using a serial interface to transmit or receive addresses or data, i.e. serial access memory
• CPC Class Codes: G11C 7/1045 Read-write mode select circuits
• CPC Class Codes: G11C 8/04 using a sequential addressing device, e.g. shift register, counter

Abstract

A serial flash memory is provided with multiple configurable pins, at least one of which is selectively configurable for use in either single-bit serial data transfers or multiple-bit serial data transfers. In single-bit serial mode, data transfer is bit-by-bit through a pin. In multiple-bit serial mode, a number of sequential bits are transferred at a time through respective pins. The serial flash memory may have 16 or fewer pins, and even 8 or fewer pins, so that low pin count packaging such as the 8-pin or 16-pin SOIC package and the 8-contact MLP/QFN/SON package may be used. The availability of the single-bit serial type protocol enables compatibility with a number of existing systems, while the availability of the multiple-bit serial type protocol enables the serial flash memory to provide data transfer rates, in systems that can support them, that are significantly faster than available with standard serial flash memories.

Claims

1. A flash memory comprising:

a flash memory array; and

an interface circuit coupled to the flash memory array, the interface circuit having a plurality of pins and being selectively compliant with a single-bit serial protocol and a multiple-bit serial protocol;

wherein a first one of the pins is configurable for single-bit serial transfer in compliance with the single-bit serial protocol; and

wherein the first pin and a second one of the pins are configurable for multiple-bit serial transfer in compliance with the multiple-bit serial protocol.

2. The flash memory of claim 1 wherein the single-bit serial protocol is Inter IC protocol.

3. The flash memory of claim 1 wherein the single-bit serial protocol is Serial Peripheral Interface protocol.

4. The flash memory of claim 1 wherein the multiple-bit serial protocol specifies concurrent transfer of two bits.

5. The flash memory of claim 1 wherein:

a third one of the pins and a fourth one of the pins are configurable for multiple-bit serial transfer in compliance with the multiple-bit serial protocol; and

the multiple bit serial protocol specifies concurrent transfer of four bits.

6. The flash memory of claim 1 wherein the first and second pins are input/output pins.

7. The flash memory of claim 1 wherein:

the first pin is a data output pin; and

the second pin is an input/output pin.

8. The flash memory of claim 7 wherein:

the first pin is configurable as a data output pin in compliance with the single-bit serial protocol during an output sequence of a “

Fast Read”

instruction;

the first pin and the second pin are configurable as data output pins in compliance with the multiple-bit serial protocol during an output sequence of a “

Fast Read Dual Output”

instruction; and

the second pin is configured as a data input pin in compliance with the single-bit serial protocol during respective input sequences of the “

Fast Read”

instruction and the “

Fast Read Dual Output”

instruction.

9. The flash memory of claim 1 wherein:

the first pin is an input/output pin; and

the second pin is a data input pin.

10. A flash memory comprising:

a flash memory array; and

an interface circuit coupled to the flash memory array, the interface circuit having a clock pin, a chip select pin, and first, second, third and fourth pins, and being selectively compliant with Serial Peripheral Interface protocol and a four-bit serial protocol;

wherein the first pin is configurable as a data output pin and the second pin is configurable as a data input pin for single-bit serial transfer in compliance with the Serial Peripheral Interface protocol; and

wherein the first, second, third and fourth pins are further configurable as input/output pins for four-bit serial transfers in compliance with the four-bit serial protocol.

11. The flash memory of claim 10 wherein:

the third pin is further configurable as a write protect pin in compliance with the Serial Peripheral Interface protocol; and

the fourth pin is further configurable as a hold pin in compliance with the Serial Peripheral Interface protocol.

12. A flash memory comprising:

a flash memory array; and

an interface circuit coupled to the flash memory array, the interface circuit having a plurality of pins and being selectively compliant with a single-bit serial protocol and a multiple-bit serial protocol;

wherein a first one of the pins is selectively configurable as a data input in compliance with the single bit serial protocol and as a data input/output in compliance with the multiple bit serial protocol; and

wherein a second one of the pins is selectively configurable as a data output in compliance with the single bit serial protocol and as a data input/output in compliance with the multiple bit serial protocol.

13. The flash memory of claim 12 wherein the single-bit serial protocol is Serial Peripheral Interface.

14. The flash memory of claim 12 wherein the multiple bit serial protocol specifies concurrent transfer of two bits.

15. The flash memory of claim 12 wherein:

a third one of the pins and a fourth one of the pins are data input/output in compliance with the multiple bit serial protocol; and

the multiple bit serial protocol specifies concurrent transfer of four bits.

16. A flash memory comprising:

a flash memory array; and

an interface circuit coupled to the flash memory array, the interface circuit comprising a plurality of pins and being selectively compliant with a single-bit serial protocol and a multiple-bit serial protocol;

wherein a first one of the pins is selectively configurable as a data input in compliance with the single bit serial protocol and as a data input in compliance with the multiple bit serial protocol;

wherein a second one of the pins is selectively configurable as a data output in compliance with the single bit serial protocol and as a data output in compliance with the multiple bit serial protocol; and

wherein a third one of the pins is a data input/output in compliance with the multiple bit serial protocol.

17. The flash memory of claim 16 wherein the single-bit serial protocol is Serial Peripheral Interface.

18. The flash memory of claim 16 wherein the multiple bit serial protocol specifies concurrent transfer of two bits.

19. The flash memory device of claim 16 wherein:

a fourth one of the pins and a fifth one on the pins are data input/output in compliance with the multiple bit serial protocol; and

the multiple bit serial protocol specifies concurrent transfer of four bits.

20. A flash memory comprising:

a flash memory array; and

an interface circuit coupled to the flash memory array, the interface circuit comprising a plurality of pins and being selectively compliant with a single-bit serial protocol and a multiple-bit serial protocol;

wherein a first one of the pins is selectively configurable as a data input/output in compliance with the single bit serial protocol and as a data input/output in compliance with the multiple bit serial protocol; and

wherein a second one of the pins is a data input/output in compliance with the multiple bit serial protocol.

21. The flash memory device of claim 20 wherein the single-bit serial protocol is Inter IC.

22. The flash memory of claim 20 wherein the multiple bit serial protocol specifies concurrent transfer of two bits.

23. The flash memory of claim 20 wherein:

a third one of the pins and a fourth one of the pins are data input/output in compliance with the multiple bit serial protocol; and

the multiple bit serial protocol specifies concurrent transfer of four bits.

24. A flash memory comprising:

a flash memory array; and

an interface circuit coupled to the flash memory array, the interface circuit having a plurality of pins and being selectively compliant with a single-bit serial protocol and a multiple-bit serial protocol;

wherein a first one of the pins is configurable for single-bit serial data input in compliance with the single-bit serial protocol;

wherein a second one of the pins is configurable for single-bit serial data output in compliance with the single-bit serial protocol; and

wherein the first pin and the second pin are configurable for multiple-bit serial output in compliance with the multiple-bit serial protocol.

25. A packaged flash memory device comprising:

an eight-contact SOIC or MLP package body;

a flash memory array contained in the package body;

an interface circuit contained in the package body and coupled to the flash memory array, the interface circuit being selectively compliant with a Serial Peripheral Interface protocol and an Enhanced Serial Peripheral Interface protocol; and

four or fewer data contacts, a clock contact, and a chip select contact mounted on the package body and coupled to the interface circuit, a first one of the data contacts being selectively configurable as a data input in compliance with the Serial Peripheral Interface protocol and as a data input/output in compliance with the Enhanced Serial Peripheral Interface protocol, and a second one of the data contacts being selectively configurable as a data output in compliance with the Serial Peripheral Interface protocol and as a data input/output in compliance with the Enhanced Serial Peripheral Interface protocol.

26. A packaged flash memory device operable under either a single-bit serial protocol or a multiple-bit serial protocol, comprising:

an eight-contact SOIC or MLP package body;

first and second data contacts, a clock contact, and a chip select contact mounted on the package body;

a flash memory array contained in the package body; and

an interface circuit contained in the package body and coupled to the flash memory array and to the first and second data contacts, a clock contact, and a chip select contact, the interface circuit being operable under a single-bit serial protocol to establish the first data contact as a data input and the second data contact as a data output, and operable under a multiple-bit serial protocol to establish the first and second data contacts as data input/output.

27. The flash memory of claim 26 further comprising a write protect contact and a hold contact mounted on the package body and coupled to the interface circuit.

28. The flash memory of claim 26 further comprising third and fourth data contacts coupled to the interface circuit, the interface circuit being operable under the multiple-bit serial protocol to establish the third and fourth contacts data contacts as data input/output.

29. A packaged flash memory device operable under either a single-bit serial protocol or a multiple-bit serial protocol, comprising:

an SOIC or MLP package body;

a flash memory array contained in the package body;

an interface circuit contained in the package body and coupled to the flash memory;

a clock contact coupled to the interface circuit;

a chip select contact coupled to the interface circuit; and

first and second data contacts coupled to the interface circuit, the interface circuit being operable under a single-bit serial protocol to establish the first data contact as a data input and the second data contact as a data output, and operable under a multiple-bit serial protocol to establish the first and second data contacts as data outputs.

30. A method for initializing a flash memory coupled to a controller, the flash memory being selectively compliant with a single-bit serial protocol and a multiple-bit serial protocol, the method comprising:

operating the flash memory under the single-bit serial protocol;

detecting compliance of the flash memory with the multiple-bit serial protocol; and

switching the flash memory to operation under the multiple-bit serial protocol, in response to the detecting step.

31. A method for executing code from a flash memory, comprising:

obtaining a multiple bit segment of an instruction from the flash memory;

processing the multiple bit instruction segment in a controller to initiate decode of the instruction;

obtaining an additional multiple bit segment of the instruction from the flash memory;

processing the additional multiple bit instruction segment in the controller to continue decode of the instruction;

repeating the additional multiple bit instruction segment obtaining step and the additional multiple bit instruction segment processing step until the instruction is fully decoded; and

executing the decoded instruction.

32. A method for executing code from a flash memory, comprising:

obtaining a multiple bit segment of an instruction from the flash memory;

storing the multiple bit instruction segment in a controller;

obtaining an additional multiple bit segment of the instruction from the flash memory;

storing the additional multiple bit instruction segment in the controller;

repeating the additional multiple bit instruction segment obtaining step and the additional multiple bit instruction segment storing step until the instruction is fully assembled; and

decoding the instruction promptly upon full assembly thereof.