Advanced Micro Devices Corporation

Chips and Technologies, Llc.

Stuart T Auvinen

Barry Alan Hoberman

David Jonq Wang

William Harry Nale

Patrick Wang

Richard Sowell

Rashid N Khan

Funkai Liu

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.

Software programmable edge delay for SRAM write enable signals on dual

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.

RAM based FIFO memory half-full detection apparatus and method

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.

Data cache management system with test mode using index registers and

A method and apparatus which puts a cartridge memory, such as a cartridge ROM, into the EMS memory space. A register value is set to indicate that the cartridge memory is present. This value is provided to enable a logic circuit which does the address transformation needed for EMS and generates a chip select signal for the cartridge memory. The chip select signal is produced upon the detection of an address directed to the cartridge memory. A register stores the address of the cartridge memory. Since the memory address of the cartridge memory can be varied, the location of the cartridge can be placed where it is most convenient for the particular memory structure of a system.

Method and apparatus for use of expanded memory system (EMS) to access

An apparatus and method for operating a system component in a microprocessor system. The component is operated by a component controller which runs off a clock having a frequency different than the system clock. The controller is synchronized with the system clock at the conclusion of a component access cycle. The state machine of the controller can thus operate independently of the system clock and timing options implemented by the controller need not have an even number of states.

Non-aligned DRAM state machine for page-mode DRAM control

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).

Biasing scheme for FIFO memories

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.

Interleaved sensing system for FIFO and burst-mode memories

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.

Growing community of inventors

Santa Cruz, CA, United States of America

Stuart T Auvinen