Memory controllers, systems, and methods supporting multiple request modes
A memory system includes a memory controller with a plurality N of memory-controller blocks, each of which conveys independent transaction requests over external request ports. The request ports are coupled, via point-to-point connections, to from one to N memory devices, each of which includes N independently addressable memory blocks. All of the external request ports are connected to respective external request ports on the memory device or devices used in a given configuration. The number of request ports per memory device and the data width of each memory device changes with the number of memory devices such that the ratio of the request-access granularity to the data granularity remains constant irrespective of the number of memory devices.
1. A dynamic random access memory (DRAM) device, comprising:
memory arrays;
for each one of said memory arrays, a command link for receiving data access commands respective to the one of said memory arrays from a memory controller and data links for transferring corresponding data with the memory controller;
for each one of said memory arrays, circuitry to control performance of data access commands received via the respective command link independent of whether another of said memory arrays is subject to an outstanding data access command from the memory controller; and
circuitry to implement a selected one of two mode settings, including
a first setting corresponding to a mode in which, for each one of said memory arrays, each of the corresponding data links is to be used for transferring data in association with the data access commands respective to the one of said memory arrays, and
a second setting corresponding to a mode in which, for each one of said memory arrays, only one-half of the corresponding data links are to be used for transferring data in association with the data access commands respective to the one of said memory arrays.
2. The DRAM device of claim 1 , wherein the selected one of said two mode settings is to be determined by reading at least one input pin.
3. The DRAM device of claim 1 , wherein the circuitry to implement is to configure each of said memory arrays to transfer data using a same column size but with double addressable row depth when the selected one of said two mode settings is the second setting, relative to when the selected one of said two mode settings is the first setting.
4. The DRAM device of claim 1 , wherein the circuitry to implement is to configure each one of said memory arrays to transfer with the memory controller two columns of data, using the one-half of the data links corresponding to the one of said memory arrays, when the selected one of said two mode settings is the second setting.
5. The DRAM device of claim 1 , wherein the circuitry to control for each one of said memory arrays is to perform a burst access of the respective one of said memory arrays, and is to responsively transfer corresponding data with the memory controller at successive time intervals via the corresponding data links.
6. The DRAM device of claim 1 , wherein the data links corresponding to each one of said memory arrays are sixteen in number.
7. The DRAM device of claim 1 , wherein the DRAM device further comprises groups of at least four memory banks, each one of said memory arrays being one of the at least four memory banks in a respective one of the groups, wherein each one of the data access commands is to be accompanied by a bank address, and wherein the circuitry to control is to select one of the at least four memory banks in one of the groups access by the one of the data access commands, responsive to the accompanying bank address.
8. The DRAM device of claim 7 , wherein the circuitry to control is to control threaded bank access for a respective one of the groups, such that, in the respective one of groups, each of said at least four memory banks can have a row activated no more than once during a first interval of time, but such that the circuitry to control can access activated rows in respective ones of the at least four memory banks in the respective ones of the groups during the first interval of time.
9. The DRAM device of claim 1 , wherein for each one of said memory arrays, the corresponding command link and the corresponding data links are to be operated at a common data rate, and the DRAM device further comprises circuitry to, during a calibration mode, loop back signals received from the memory controller over each command link to an outgoing transmission link for transmission of the signals back to the memory controller.
10. The DRAM device of claim 1 , wherein each command link and each of said data links is a differential link, and to be operated at a double data rate relative to a data transfer timing signal.
11. The DRAM device of claim 1 , wherein:
the first setting corresponds to a mode in which, for each one of said memory arrays, the corresponding command link and the corresponding data links are each to be operated in a point-to-point (PtoP) configuration, and
the second setting corresponds to a mode in which, for each one of said memory arrays, the corresponding command link is to be operated in a point-to-two-point (Pto2P) configuration and the half of the corresponding data links which are to be used for transferring data in association with the data access commands respective to the one of said memory arrays are each to be operated in the PtoP configuration.
12. A dynamic random access memory (DRAM) device, comprising:
memory arrays;
for each one of said memory arrays, a command link for receiving data access commands respective to the one of said memory arrays from a memory controller and data links for transferring corresponding data with the memory controller;
for each one of said memory arrays, circuitry to control performance of data access commands received via the respective command link independent of whether another of said memory arrays is subject to an outstanding data access command from the memory controller; and
circuitry to implement a selected one of two mode settings, including
a first setting corresponding to a mode in which, for each one of said memory arrays, each of the corresponding data links is to be used for transferring data in association with the data access commands respective to the one of said memory arrays, and
a second setting corresponding to a mode in which, for each one of said memory arrays, only one-half of the corresponding data links are to be used for transferring data in association with the data access commands respective to the one of said memory arrays;
wherein the selected one of said two mode settings is to be determined by reading at least one input pin, and wherein the circuitry to implement is to configure each of said memory arrays to transfer data using a same column size but with double addressable row depth when the selected one of said two mode settings is the second setting, relative to when the selected one of said two mode settings is the first setting.
13. The DRAM device of claim 12 , wherein the circuitry to control for each one of said memory arrays is to perform a burst access of the respective one of said memory arrays, and is to responsively transfer corresponding data with the memory controller at successive time intervals via the corresponding data links.
14. The DRAM device of claim 12 , wherein the data links corresponding to each one of said memory arrays are sixteen in number.
15. The DRAM device of claim 12 , wherein the DRAM device further comprises groups of at least four memory banks, each one of said memory arrays being one of the at least four memory banks in a respective one of the groups, wherein each one of the data access commands is to be accompanied by a bank address, and wherein the circuitry to control is to select one of the at least four memory banks in one of the groups access by the one of the data access commands, responsive to the accompanying bank address.
16. The DRAM device of claim 15 , wherein the circuitry to control is to control threaded bank access for a respective one of the groups, such that, in the respective one of groups, each of said at least four memory banks can have a row activated no more than once during a first interval of time, but such that the circuitry to control can access activated rows in respective ones of the at least four memory banks in the respective ones of the groups during the first interval of time.
17. A dynamic random access memory (DRAM) device, comprising:
memory arrays;
for each one of said memory arrays, a command link for receiving data access commands respective to the one of said memory arrays from a memory controller and data links for transferring corresponding data with the memory controller;
for each one of said memory arrays, circuitry to control performance of data access commands received via the respective command link independent of whether another of said memory arrays is subject to an outstanding data access command from the memory controller; and
circuitry to implement a selected one of two mode settings, including
a first setting corresponding to a mode in which, for each one of said memory arrays, each of the corresponding data links is to be used for transferring data in association with the data access commands respective to the one of said memory arrays, and
a second setting corresponding to a mode in which, for each one of said memory arrays, only one-half of the corresponding data links are to be used for transferring data in association with the data access commands respective to the one of said memory arrays;
wherein the selected one of said two mode settings is to be determined by reading at least one input pin, and wherein the circuitry to implement is to configure each one of said memory arrays to transfer with the memory controller two columns of data, using the one-half of the data links corresponding to the one of said memory arrays, when the selected one of said two mode settings is the second setting.
18. The DRAM device of claim 17 , wherein the circuitry to control for each one of said memory arrays is to perform a burst access of the respective one of said memory arrays, and is to responsively transfer corresponding data with the memory controller at successive time intervals via the corresponding data links.
19. The DRAM device of claim 17 , wherein the data links corresponding to each one of said memory arrays are sixteen in number.
20. The DRAM device of claim 17 , wherein the DRAM device further comprises groups of at least four memory banks, each one of said memory arrays being one of the at least four memory banks in a respective one of the groups, wherein each one of the data access commands is to be accompanied by a bank address, and wherein the circuitry to control is to select one of the at least four memory banks in one of the groups access by the one of the data access commands, responsive to the accompanying bank address.
21. The DRAM device of claim 20 , wherein the circuitry to control is to control threaded bank access for a respective one of the groups, such that, in the respective one of groups, each of said at least four memory banks can have a row activated no more than once during a first interval of time, but such that the circuitry to control can access activated rows in respective ones of the at least four memory banks in the respective ones of the groups during the first interval of time.