Synchronous memory device
First Claim
1. A synchronous memory device having a memory cell array divided into a plurality of subarrays, wherein each subarray includes a plurality of subarray sections, the memory device comprising:
- clock receiver circuitry to receive an external clock signal from an external bus;
clock generation circuitry, coupled to the clock receiver circuitry, to generate a first internal clock signal having a clock edge which is synchronized with the external clock signal and to generate a second internal clock signal having a clock edge which is synchronized with the external clock signal;
a first subarray section having a first internal I/O line to access data from a first memory cell location and a second internal I/O line to access data from a second memory cell location, wherein the first and second memory cell locations are in the first subarray section;
a second subarray section having a first internal I/O line to access data from a third memory cell location and a second internal I/O line to access data from a fourth memory cell location, wherein the third and fourth memory cell locations are in the second subarray section;
output driver circuitry, including a first output driver and a second output driver, to output data onto the external bus in response to a read request; and
multiplexer circuitry, coupled to the output driver circuitry, wherein;
the multiplexer circuitry couples the first internal I/O line of the first subarray section to an input of the first output driver and couples the first internal I/O line of the second subarray section to an input of the second output driver in response to the clock edge of the first internal clock signal; and
the multiplexer circuitry couples the second internal I/O line of the first subarray section to an input of the first output driver and couples the second internal I/O line of the second subarray section to an input of the second output driver in response to the clock edge of the second internal clock signal.
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Reexamination
Accused Products
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.
180 Citations
37 Claims
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1. A synchronous memory device having a memory cell array divided into a plurality of subarrays, wherein each subarray includes a plurality of subarray sections, the memory device comprising:
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clock receiver circuitry to receive an external clock signal from an external bus; clock generation circuitry, coupled to the clock receiver circuitry, to generate a first internal clock signal having a clock edge which is synchronized with the external clock signal and to generate a second internal clock signal having a clock edge which is synchronized with the external clock signal; a first subarray section having a first internal I/O line to access data from a first memory cell location and a second internal I/O line to access data from a second memory cell location, wherein the first and second memory cell locations are in the first subarray section; a second subarray section having a first internal I/O line to access data from a third memory cell location and a second internal I/O line to access data from a fourth memory cell location, wherein the third and fourth memory cell locations are in the second subarray section; output driver circuitry, including a first output driver and a second output driver, to output data onto the external bus in response to a read request; and multiplexer circuitry, coupled to the output driver circuitry, wherein; the multiplexer circuitry couples the first internal I/O line of the first subarray section to an input of the first output driver and couples the first internal I/O line of the second subarray section to an input of the second output driver in response to the clock edge of the first internal clock signal; and the multiplexer circuitry couples the second internal I/O line of the first subarray section to an input of the first output driver and couples the second internal I/O line of the second subarray section to an input of the second output driver in response to the clock edge of the second internal clock signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A synchronous memory device having a memory cell array divided into a plurality of subarrays, including a first subarray and a second subarray wherein each subarray includes a plurality of subarray sections, the memory device comprises:
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clock receiver circuitry to receive an external clock signal from an external bus; clock generation circuitry, coupled to the clock receiver circuitry, to generate a first internal clock signal having a clock edge which is synchronized with the external clock signal and to generate a second internal clock signal having a clock edge which is synchronized with the external clock signal; a first subarray section of a first subarray, the first subarray section having a first internal I/O line to access data from a first memory cell location and a second internal I/O line to access data from a second memory cell location, wherein the first and second memory cell locations are in the first subarray section; a second subarray section of a second subarray, the second subarray section having a first internal I/O line to access data from a third memory cell location and a second internal I/O line to access data from a fourth memory cell location, wherein the third and fourth memory cell locations are in the second subarray section; output driver circuitry, including a first output driver and a second output driver, to output data onto the external bus in response to a read request; and multiplexer circuitry, coupled to the output driver circuitry, wherein; the multiplexer circuitry couples the first internal I/O line of the first subarray section to an input of the first output driver and couples the first internal I/O line of the second subarray section to an input of the second output driver in response to the clock edge of the first internal clock signal; and the multiplexer circuitry couples the second internal I/O line of the first subarray section to an input of the first output driver and couples the second internal I/O line of the second subarray section to an input of the second output driver in response to the clock edge of the second internal clock signal. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A memory system having a synchronous memory device coupled to a bus, the memory device having a memory cell array divided into a plurality of subarrays, wherein each subarray includes a plurality of subarray sections, the memory system comprises:
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clock receiver circuitry to receive a bus clock from the bus; clock generation circuitry to generate a first clock edge which is synchronized with the bus clock and to generate a second clock edge which is synchronized with the bus clock; a first subarray section having a first data line to access data from a first memory cell location and a second data line to access data from a second memory cell location, wherein the first and second memory cell locations are in the first subarray section; a second subarray section having a first data line to access data from a third memory cell location and a second data line to access data from a fourth memory cell location, wherein the third and fourth memory cell locations are in the second subarray section; output drivers, including a first output driver and a second output driver, to output a predetermined amount of data onto the bus in response to a read request; and multiplexer circuitry, coupled to the output drivers, wherein; the multiplexer circuitry couples the first data line of the first subarray section to an input of the first output driver and couples the first data line of the second subarray section to an input of the second output driver in response to the first clock edge; and the multiplexer circuitry couples the second data line of the first subarray section to an input of the first output driver and couples the second data line of the second subarray section to an input of the second output driver in response to the second clock edge. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37)
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Specification