High-performance memory controller with application-programmable optimization
First Claim
1. A memory controller, adapted to receive access signals from a memory-access device, for responding thereto by controlling a page-mode multiplexed-address memory adapted for reception of memory-address, row-address-strobe, and column-address-strobe signals, the memory keeping a row address latched therein in response to a first, hold state of the row-address-strobe signal and precharging in response to a second, precharge state of the row-address-strobe signal, the memory controller comprising:
- A) a programmable timer responsive to a program signal to store a duration value set thereby and generate a timeout signal when the controller, has been idle, along with the row-address-strobe signal in the hold state, for a time interval the duration of which stored duration value represents; and
B) a memory operator connected to receive the timeout signal and being responsive to the access signals to access the memory by applying address, row-address-strobe, and column-address-strobe signals thereto, the memory operator keeping the row-address-strobe signal in the hold state during idle periods after an access until it receives the timeout signal and then switching the row-address-strobe signal to its precharge level.
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Accused Products
Abstract
A memory controller (18) for controlling a multiplexed-address memory (14) includes a programmable timer (22) whose time-out period can be controlled by the memory-access device (12) to which the memory controller (18) provides memory access. During an idle period after a memory access, the controller'"'"'s memory operator (20) keeps the row-address-strobe signal asserted, and thereby permits page-mode addressing on the next cycle, until the counter (22) times out, at which point the memory operator (20) releases the row- address-strobe line and thereby initiates the pre-charge operation that is required before a row-address change. The memory access device (12) can thus change the time for which the row-address-strobe signal is kept asserted after a cycle to different values for different applications that it is running. The memory-access device (12) can thus optimize, on an application-specific basis, the compromise between the pre-charge penalties of page misses and the column-address-only benefits of page hits.
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Citations
2 Claims
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1. A memory controller, adapted to receive access signals from a memory-access device, for responding thereto by controlling a page-mode multiplexed-address memory adapted for reception of memory-address, row-address-strobe, and column-address-strobe signals, the memory keeping a row address latched therein in response to a first, hold state of the row-address-strobe signal and precharging in response to a second, precharge state of the row-address-strobe signal, the memory controller comprising:
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A) a programmable timer responsive to a program signal to store a duration value set thereby and generate a timeout signal when the controller, has been idle, along with the row-address-strobe signal in the hold state, for a time interval the duration of which stored duration value represents; and B) a memory operator connected to receive the timeout signal and being responsive to the access signals to access the memory by applying address, row-address-strobe, and column-address-strobe signals thereto, the memory operator keeping the row-address-strobe signal in the hold state during idle periods after an access until it receives the timeout signal and then switching the row-address-strobe signal to its precharge level. - View Dependent Claims (2)
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Specification