Semiconductor memory device with pipeline access
First Claim
1. A memory drive comprising:
- an array of memory cells;
accessing means for reading selected data from the array based upon a read address and for storing such data in a data latch;
a counter with means for incrementing the counter;
input address terminals for the device;
a comparator;
coupling means applying an input address from said terminals to said counter, to said accessing means and to one input of said comparator;
an address latch having an input connected to receive the incremented contents of the counter an output connected to an input of the comparator;
and means for activating either said accesssing means or said data latch in response to an output of the comparator.
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Accused Products
Abstract
A semiconductor memory device contains an on-chip self-incrementing counter which may be loaded from address input terminals, so that the memory cell array may be accessed using either an incoming address or the last address incremented by one. Also, the incremented last address is saved in a latch. A comparator receives the present address and incremented last address, and if these match a data output is available immediately. After a read cycle, the array is always accessed using the incremented last address, so when another fetch is initiated from the CPU, if it is for the next sequential address, the data is already available in a data ouput latch and the apparent access time is much less than that of the memory array.
61 Citations
15 Claims
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1. A memory drive comprising:
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an array of memory cells; accessing means for reading selected data from the array based upon a read address and for storing such data in a data latch; a counter with means for incrementing the counter; input address terminals for the device; a comparator; coupling means applying an input address from said terminals to said counter, to said accessing means and to one input of said comparator; an address latch having an input connected to receive the incremented contents of the counter an output connected to an input of the comparator; and means for activating either said accesssing means or said data latch in response to an output of the comparator. - View Dependent Claims (2, 3, 4)
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5. A memory device comprising an array of memory cells, an address input to the device for connection to external means, a data output from the device for connection to external bus means, a data latch coupling an output of the array to said data output, control terminals for the device for connection to external control lines for transfer of control signals, and addressing means within the device coupling said address input to the array;
said addressing means comprising; a counter having an input coupled to said address input, with means for incrementing the counter, a comparator having first and second inputs and a compare output, the first input being connected to receive the incremented output from the counter, an address latch connected to receive the incremented output of the counter, an output of the address latch coupled to the second input of the comparator, a control output to one of said control terminals to signal that valid data is presented to said data output, and means responsive to said compare output to activate the data latch and the control output. - View Dependent Claims (6, 7, 8, 9)
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10. A processor system comprising:
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processor means having address and data bus means and control lines and functioning to send out addresses on said bus means and to receive data from the bus means under control of signals on said control lines; a memory device having an array of memory cells, an address input to the device connected to said bus means, a data output from the device connected to said bus means, a data latch coupling an output of the array to said data output, control terminals for the device connected to said control lines, and addressing means within the device coupling said address to the array; said addressing means comprising; a counter having an input coupled to said address input, with means for incrementing the counter, a comparator having first and second inputs and a compare output, the first input being connected to receive the incremented output from the counter, an address latch connected to receive the incremented output of the counter, an output of the address latch coupled to the second input of the comparator, a control output to one of said control terminals to signal that valid data is presented to said data output, and means responsive to said compare output to activate the data latch and the control output. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification