Integrated circuit I/O using a high performance bus interface
DCFirst Claim
1. A memory device comprising:
- a first circuit for receiving a bus clock from a bus and for generating at least one internal clock; and
receiver circuitry coupled to the first circuit to receive the at least one internal clock, the receiver circuit samples information on the bus in response to the at least one internal clock to acquire even bus cycle information and odd bus cycle information from the bus.
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Abstract
The present invention includes a memory subsystem comprising at least two semiconductor devices, including at least one memory device, connected to a bus, where the bus includes a plurality of bus lines for carrying substantially all address, data and control information needed by said memory devices, where the control information includes device-select information and the bus has substantially fewer bus lines than the number of bits in a single address, and the bus carries device-select information without the need for separate device-select lines connected directly to individual devices.
The present invention also includes a protocol for master and slave devices to communicate on the bus and for registers in each device to differentiate each device and allow bus requests to be directed to a single or to all devices. The present invention includes modifications to prior-art devices to allow them to implement the new features of this invention. In a preferred implementation, 8 bus data lines and an AddressValid bus line carry address, data and control information for memory addresses up to 40 bits wide.
282 Citations
45 Claims
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1. A memory device comprising:
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a first circuit for receiving a bus clock from a bus and for generating at least one internal clock; and receiver circuitry coupled to the first circuit to receive the at least one internal clock, the receiver circuit samples information on the bus in response to the at least one internal clock to acquire even bus cycle information and odd bus cycle information from the bus.
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2. A memory device comprising:
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a first circuit for receiving an external clock from a bus and for providing a first internal clock and a second internal clock; and receiver circuitry coupled to the first circuit to receive the first internal clock and the second internal clock, the receiver circuitry samples information on the bus in response to the first internal clock and the second internal clock, wherein the receiver circuitry comprises; a first input receiver coupled to the first circuit, the first input receiver samples information on the bus in response to the first internal clock to acquire even bus cycle information; and a second input receiver coupled to the first circuit, the second input receiver samples information on the bus in response to the second internal clock to acquire odd bus cycle information.
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3. A semiconductor device having memory, the device comprising:
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a clock circuit to provide a first clock signal and a second clock signal; a first input receiver coupled to the clock circuit to receive the first clock signal, wherein in response to the first clock signal, the first input receiver senses a bus signal on a bus; a second input receiver coupled to the clock circuit to receive the second clock signal, wherein in response to the second clock signal, the second input receiver senses the bus signal, and wherein the first and second input receivers are selected alternately by the clock circuit. - View Dependent Claims (4, 5, 6, 7, 8, 9)
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10. A memory device comprising:
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a first circuit to receive an external clock signal and to provide a first internal clock signal and a second internal clock signal; a multiplexer coupled to the first circuit to receive the first internal clock and second internal clock, the multiplexer including an output and first and second inputs; a first output line coupled to the first input of the multiplexer; a second output line coupled to the second input of the multiplexer; an output driver having an output coupled to the bus, an input coupled to the output of the multiplexer, the output driver for driving data on the bus in response to the output of the multiplexer; and wherein the multiplexer couples the first output line to the output of the multiplexer in response to the first internal clock to provide even bus cycle information to the bus, and couples the second output line to the output of the multiplexer in response to the second internal clock to provide odd bus cycle information to the bus.
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11. A memory device comprising:
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a first circuit to generate at least one internal clock; and output circuitry having a pair of inputs and an output, the output being coupled to a bus, the output circuitry alternately selects one or the other of the pair of inputs in response to the at least one internal clock to provide even and odd bus cycle information to the bus.
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12. A semiconductor device having memory, comprising:
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A clock circuit to provide a first clock signal and a second clock signal; a multiplexer coupled to the clock circuit to receive the first and second clock signals, the multiplexer having an output, a first input coupled to a first output line and a second input coupled to a second output line; an output driver including; (1) an output coupled to a bus and (2) an input coupled to an output of the multiplexer, wherein the output driver drives data onto the bus; wherein the multiplexer couples the first output line to the output of the multiplexer in response to the first clock signal; and the multiplexer couples the second output line to the output of the multiplexer in response to the second clock signal. - View Dependent Claims (13, 14, 15, 16)
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17. A synchronous random access memory, comprising:
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a selection circuit for generating a first selection signal and a second selection signal in response to at least one bus clock; a first input receiver coupled to the first selection circuit, the first input receiver, in response to the first selection signal, senses a signal on a bus; a second input receiver coupled to the second selection circuit, the second input receiver, in response to the second selection signal, senses a signal on the bus, wherein selection circuit selects the first and second input receivers to sense signals on the bus synchronous with respect to the at least one bus clock. - View Dependent Claims (18, 19)
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20. A synchronous random access memory, comprising:
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a selection circuit for providing a first selection signal and a second selection signal in response to at least one bus clock; a multiplexer coupled to the selection circuit, the multiplexer includes an output and at least first and second inputs; an output driver including; (1) an output coupled to a bus and, (2) an input coupled to the output of the multiplexer, wherein the output driver drives data onto the bus; a first output line coupled to the first input of the multiplexer, wherein the multiplexer couples the first output line to the output of the multiplexer in response to the first selection signal; a second output line coupled the second input of the multiplexer, wherein the multiplexer couples the second output line to the output of the multiplexer in response to the second selection signal; wherein the output driver drives data onto the bus synchronously with respect to at least the one bus clock. - View Dependent Claims (21, 22, 23)
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24. A synchronous memory device having at least one memory section which includes a plurality of memory cells, the memory device comprises:
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clock receiver circuitry to receive at least one external clock signal; clock generation circuitry, coupled to the clock receiver circuitry, to generate a first internal clock signal and a second internal clock signal; input receiver circuitry coupled to the clock generation circuitry to receive the first and second internal clock signals, the input receiver circuitry samples information on a bus in response to the first and second internal clock signals and synchronously with respect to at least the one external clock signal. - View Dependent Claims (25, 26)
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27. A memory device having at least one memory section which includes a plurality of memory cells, the memory device comprises:
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a first clock receiver to receive a first external clock signal; a second clock receiver to receive a second external clock signal; and input receiver circuitry, coupled to the first and second clock receivers, to sample information on a bus synchronously with respect to the first and second external clock signals. - View Dependent Claims (28, 29, 30)
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31. A synchronous memory device having at least one memory section which includes a plurality of memory cells, the memory device comprises:
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internal clock generation circuitry to generate a first internal clock signal and a second internal clock signal, wherein the internal clock generation circuit generates the first and second internal clock signals using at least a first external clock; an output driver, coupled to the internal clock generation circuitry, the output driver outputs data on a bus in response to the first and second internal clock signals and synchronously with respect to at least the first external clock signal. - View Dependent Claims (32, 33, 34, 35)
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36. A synchronous memory device having at least one memory section which includes a plurality of memory cells, wherein the memory device receives first and second external clock signals and outputs data on a bus, the memory device comprises:
a plurality of output drivers, each output driver being coupled to the bus to output data on the bus synchronously with respect to the first and second external clock signals. - View Dependent Claims (37, 38, 39, 40, 41, 42)
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43. A synchronous dynamic random access memory having at least one memory section which includes a plurality of memory cells, the memory device comprises:
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internal clock generation circuitry to generate a first internal clock signal and a second internal clock signal; a multiplexer having an output and at least two inputs, the multiplexer being coupled to internal clock generation circuitry to receive the first and a second internal clocks; an output driver having an output and an input, the input being coupled to the output of the multiplexer, a first data output line coupled to the first input of the multiplexer, wherein the multiplexer couples the first data output line to the output of the multiplexer in response to the first internal clock signal; and a second data output line coupled to the second input of the multiplexer, wherein the multiplexer couples the second data output line to the output of the multiplexer in response to the second internal clock signal wherein the output driver drives data on a bus synchronously with respect to first and second external clock signals. - View Dependent Claims (44, 45)
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Specification