Configurable multirank memory system with interface circuit
First Claim
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1. A memory module comprising:
- a first rank of memory circuits comprising a first memory circuit;
a second rank of memory circuits comprising a second memory circuit;
an interface circuit;
a first data bus that connects to the first memory circuit, the second memory circuit, and the interface circuit, the first data bus having a first data bus width; and
a second data bus that connects to the interface circuit and a memory controller, the second data bus having a second data bus width, wherein the second data bus width is narrower than the first data bus width;
wherein the interface circuit is operable to;
receive a first read command from the memory controller to read first data stored in the first memory circuit;
after receiving the first read command, receive a second read command from the memory controller to read second data that is stored in the second memory circuit;
enable a chip select pin of the first memory circuit to connect the first memory circuit to the first data bus;
read the first data from the first memory circuit across the first data bus;
transmit the first data to the memory controller across the second data bus;
insert idle clock cycles, and during the idle clock cycles;
(i) disable the chip select pin of the first memory circuit to disconnect the first memory circuit from the first data bus, and(ii) enable a chip select pin of the second memory circuit to connect the second memory circuit to the first data bus, while the first data is being transmitted to the memory controller across the second data bus;
read the second data from the second memory circuit across the first data bus; and
transmit the second data to the memory controller across the second data bus without a delay on the second data bus between the first data and the second data.
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Abstract
An interface circuit that is configured to receive a first read command from a memory controller to read first data stored in a first memory circuit and a second read command to read second data that is stored in a second memory circuit, and transmit the first data and the second data to the memory controller across a data bus without a delay on the data bus between the first data and the second data.
888 Citations
20 Claims
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1. A memory module comprising:
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a first rank of memory circuits comprising a first memory circuit; a second rank of memory circuits comprising a second memory circuit; an interface circuit; a first data bus that connects to the first memory circuit, the second memory circuit, and the interface circuit, the first data bus having a first data bus width; and a second data bus that connects to the interface circuit and a memory controller, the second data bus having a second data bus width, wherein the second data bus width is narrower than the first data bus width; wherein the interface circuit is operable to; receive a first read command from the memory controller to read first data stored in the first memory circuit; after receiving the first read command, receive a second read command from the memory controller to read second data that is stored in the second memory circuit; enable a chip select pin of the first memory circuit to connect the first memory circuit to the first data bus; read the first data from the first memory circuit across the first data bus; transmit the first data to the memory controller across the second data bus; insert idle clock cycles, and during the idle clock cycles; (i) disable the chip select pin of the first memory circuit to disconnect the first memory circuit from the first data bus, and (ii) enable a chip select pin of the second memory circuit to connect the second memory circuit to the first data bus, while the first data is being transmitted to the memory controller across the second data bus; read the second data from the second memory circuit across the first data bus; and transmit the second data to the memory controller across the second data bus without a delay on the second data bus between the first data and the second data. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A sub-system comprising:
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an interface circuit; a first memory module comprising; a first rank of memory circuits comprising a first memory circuit; a second memory module comprising; a second rank of memory circuits comprising a second memory circuit; a first data bus that connects to the first memory module, the second memory module, and the interface circuit, the first data bus having a first data bus width; and a second data bus that connects to the interface circuit and a memory controller, the second data bus having a second data bus width, wherein the second data bus width is narrower than the first data bus width; wherein the interface circuit is operable to; receive a first read command from the memory controller to read first data stored in the first memory circuit; after receiving the first read command, receive a second read command from the memory controller to read second data that is stored in the second memory circuit; enable a chip select pin of the first memory circuit to connect the first memory circuit to the first data bus; read the first data from the first memory circuit across the first data bus; transmit the first data to the memory controller across the second data bus; insert idle clock cycles, and during the idle clock cycles; (i) disable the chip select pin of the first memory circuit to disconnect the first memory circuit from the first data bus, and (ii) enable a chip select pin of the second memory circuit to connect the second memory circuit to the first data bus, while the first data is being transmitted to the memory controller across the second data bus; read the second data from the second memory circuit across the first data bus; and transmit the second data to the memory controller across the second data bus without a delay on the second data bus between the first data and the second data. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A computer-implemented method, comprising:
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receiving, from a memory controller by an interface circuit, a first read command to read first data stored in a first memory circuit; after receiving the first read command, receiving a second read command from the memory controller to read second data that is stored in a second memory circuit; enabling a chip select pin of the first memory circuit to connect the first memory circuit to a first data bus, wherein the first data bus is connected to the first memory circuit, the second memory circuit, and the interface circuit, and wherein the first data bus has a first data bus width; reading the first data from the first memory circuit across the first data bus; transmitting the first data to the memory controller across a second data bus, wherein the second data bus is connected to the interface circuit and the memory controller, wherein the second data bus has a second data bus width that is narrower than the first data bus width; inserting idle clock cycles, and during the idle clock cycles; (i) disabling the chip select pin of the first memory circuit to disconnect the first memory circuit from the first data bus, and (ii) enabling a chip select pin of the second memory circuit to connect the second memory circuit to the first data bus, while the first data is being transmitted to the memory controller across the second data bus; reading the second data from the second memory circuit across the first data bus; and transmitting the second data to the memory controller across the second data bus without a delay on the second data bus between the first data and the second data. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification