Memory system and method with serial and parallel modes

• US 20080137461A1
• Filed: 12/12/2006
• Published: 06/12/2008
• Est. Priority Date: 12/12/2006
• Status: Active Grant

• Current Assignee: Mosaid Technologies Incorporated (MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management))
• Original Assignee: Mosaid Technologies Incorporated (MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management))
• Inventors: Kim, Jin-Ki, Oh, HakJune, Pyeon, Hong Beom
• Granted Patent: US 7,529,149 B2
• Time in Patent Office: Days
• US Class Current: 365/219
• CPC Class Codes: G11C 2207/107 Serial-parallel conversion of data or prefetch
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor
• CPC Class Codes: G11C 7/1045 Read-write mode select circuits
• 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 7/1075 for multiport memories each having random access ports and serial ports, e.g. video RAM
• CPC Class Codes: G11C 7/1078 Data input circuits, e.g. write amplifiers, data input buffers, data input registers, data input level conversion circuits

Abstract

Methods and systems are provided that allow the method of access to one or more memory banks to be performed using serial access, or using parallel access. In serial mode, each link operates as an independent serial link. In contrast, during serial mode, the links operate in common as a parallel link. Where input and output controls are received independently for each link for serial mode, a single set of input and output controls is used in common by all of the links during parallel mode.

Claims

1. A memory system comprising:

at least one memory bank;

interface circuitry operable with a plurality of modes, for connecting a plurality of inputs and a plurality of outputs to the at least one memory bank, the interface circuitry having a serial mode during which each of at least one input operates as a respective serial input and each of at least one output operates as a respective serial output, the interface circuitry having a parallel mode during which the inputs operate collectively as a parallel input and the outputs operate collectively as a parallel output.

2. The memory system of claim 1 wherein the at least one memory bank comprises a plurality of memory banks.

3. The memory system of claim 2 wherein during serial mode, the at least one input that each operates as a respective serial input comprises a plurality of the inputs, and the at least one output that operates as a respective serial output comprises a plurality of the outputs.

4. The memory system of claim 3 wherein the interface circuitry comprises dual-mode interface circuitry comprising:

a plurality of link and bank controllers each having a respective input of the plurality of inputs;

wherein each of the plurality of link and bank controllers is operable in serial mode to perform read and write operations in a serial manner by processing for each read and write operation a single bitwidth input signal received on the respective input containing command, address and data if the operation is write operation;

wherein the plurality of link and bank controllers are operable collectively in parallel mode to perform read and write operations in parallel by processing for each read and write operation a multiple bitwidth input signal received on multiple inputs containing command, address and data if the operation is a write operation.

5. The memory system of claim 4 wherein each link and bank controller is connected to a predetermined one of the memory banks and each memory bank is connected to a predetermined one of the outputs.

6. The memory system of claim 4 wherein:

each link and bank controller further comprises a respective input control for write operations and a respective output control for read operations;

the dual mode interface circuitry is operable during parallel mode to connect the input control of a common one of the plurality of link and bank control circuits to the input control of the remaining link and bank control circuits and to connect the output control of the common of the plurality of link and bank control circuits to the output control of the remaining link and bank circuits such that during parallel mode all of the link and bank control circuits operate in common;

the dual mode interface circuitry is operable during the serial mode to allow independent signals to be received at each input control and output control.

7. The memory system of claim 4 wherein the plurality of link and bank controllers comprise a respective link and bank controller for each memory bank.

8. The memory system of claim 4 further comprising:

at least one link switch that operates during serial mode to connect each link and bank controller to a respective selected bank and that operates during parallel mode to connect all of the link and bank controllers to a selected memory bank.

9. The memory system of claim 8 wherein:

the at least one link switch comprises a first link switch that connects each link to a respective selected bank for write and control, and a second link switch that connects each link to the selected bank for read, preventing simultaneous connection of multiple links to the same bank.

10. The memory system of claim 1 wherein the dual mode interface circuitry comprises:

an input receiving a data width control input that selects between serial mode and parallel mode.

11. The memory system of claim 4 wherein the dual mode interface circuit comprises:

an input for receiving a data width control input signal that selects between serial mode and parallel mode;

for each link and bank controller a respective first multiplexer having first and second inputs, each first input connected to the respective input control of the link and bank controller, each second input connected to the input control of a common one of the link and bank controllers, the first multiplexer operable to select the first input or the second input under control of the data control width control input;

for each link and bank controller, a respective second multiplexer having first and second inputs, each first input connected to the respective output control of the link and bank controller, each second input connected to the output control of the common one of the link and bank controllers, the second multiplexer operable to select the first input or the second input under control of the data control width control input signal.

12. The memory system of claim 1 wherein the interface circuitry comprises dual mode interface circuitry comprising:

for each memory bank, a respective parallel to serial converter having a serial output;

switching logic that switches the serial output of each parallel to serial converter towards a selected output.

13. The memory system of claim 12 further comprising:

selector logic for selecting serial outputs of the parallel to serial converters during serial mode, and for selecting a parallel output during parallel mode.

14. The memory system of claim 13 further comprising:

a data width converter that produces said parallel output by converting an output from a selected bank from a data width for bank access to a data width equal to the number of outputs of said plurality outputs.

15. The memory system of claim 1 wherein the interface circuitry comprises dual mode interface circuitry comprising:

for each memory bank, a respective serial to parallel to converter;

switching logic that switches each input to the input a respective selected one of the parallel to serial converters.

16. The memory system of claim 15 further comprising:

a data width converter that converts a parallel input having a data width equal to the number of inputs of said plurality of inputs to a data width for bank access.

17. A method comprising:

reconfiguring a memory interface into a selected one of a serial mode and a parallel mode according to a data width control input;

in serial mode, the memory interface functioning as at least one serial interface;

in parallel mode, the memory interface functioning as a parallel interface.

18. The method of claim 17 further comprising:

during serial mode, providing serial access from each link to any bank of a plurality of banks.

19. The method of claim 17 wherein reconfiguring a memory interface into a selected one of a serial mode and a parallel mode according to a data width control input comprises:

for serial mode, reconfiguring a plurality of link and bank controllers such that during serial mode, independent input and output controls are received for each of at the at least one serial interface;

for parallel mode, reconfiguring the plurality of link and bank controllers such that an input and output control received at one link and bank controller is used in common by all of the link and bank controllers.