Abstract: A programmable circuit is used to modify the write enable signal used by static RAMs in cache-based personal computer systems. More specifically, the programmable circuit is used to delay or not delay the trailing edge of the cache write enable (CWE) signals in cache-based personal computer systems thereby enabling the system to accommodate a plurality of microprocessor devices.

Abstract: A method for detecting a half-full condition of a first-in, first-out memory array. The method of the invention includes the steps of a) moving a write pointer through the array to write data to alternating rows of the memory array; b) moving a read pointer through the array to read data from the alternating rows of the memory array in first-in, first-out order; and c) providing a half-full indication when the read pointer and the write pointer point to adjacent rows in the memory array. This method eliminates the need to route lines across the array to detect a half-full condition, thereby reducing die and power requirements and offering an increase in speed.

Abstract: A memory controller which can be used with an external tag RAM is disclosed. Existing index registers in the controller serve double duty as buffers for storing tag RAM data during a test mode. Input/output lines for the external tag RAM are coupled to the index registers in addition to being coupled to a comparator for comparison with an external address during normal operation. A buffer is provided so that data from the external address from the CPU can be written through these same tag RAM input/output lines in order to update the tag RAM after a miss. In order to prevent DRAMS from putting data on the memory bus during a cache RAM test, a CAS inhibit signal is provided to the DRAM state machine. Posted writes are also disabled to avoid interference with the address provided to the tag RAM.

Abstract: A biasing circuit for use with memory cells in intermittent memories includes means coupled between first and second bit-lines for biasing continuously the first and second bit-lines during a read operation so as to compensate for any leakage of charge without consumption any power. The biasing means is formed of an N-channel MOS biasing transistor (M1) and a cross-coupled half-latch circuit formed of a first P-channel MOS transistor (M2) and a second P-channel MOS transistor (M3).

Abstract: An interleaved sensing system for decreasing the read access time in a sequential memory includes a sequential memory array formed of a plurality of memory cells for storing data. The memory cells are arranged in a plurality of odd columns and a plurality of even columns. Sensing means are provided for interleaving the stored data in the memory cells in the odd columns with the stored data in the memory cells in the even columns. An output buffer is coupled to the sensing means for generating data output representing alternately the stored data in the odd and even columns during alternate read cycles.

Abstract: In a memory circuit including a write bit-line for writing data into a memory cell, and a read bit-line for reading data from the cell, a transistor is included, connected with the write bit-line and the read bit-line, so that when a fast flush signal is applied to the gate of that transistor, direct connection is made between the write bit-line and read bit-line, so that data is written into the cell, but can be read simultaneously from the read bit-line, reducing the fall-through delay.