Advanced Micro Devices Corporation

Pradip Banerjee

Paul D Keswick

A method and apparatus for resetting a SRAM in a single DRAM-SRAM transfer cycle in a graphics system is described comprising a SRAM address decoder, a DRAM data input buffer, a reset data register and data lines. In operation, reset data is transferred into the DRAM data input buffer. Thereafter, the SRAM is isolated from the address decoder and the data lines and the reset data is transferred from the DRAM data input buffer into the reset data register. Then data is transferred in parallel between the DRAM and the SRAM. Upon completion of the transfer of data between the DRAM and the SRAM, the SRAM is recoupled to the data lines. After the SRAM is recoupled to the data lines, the reset data is transferred in parallel to the SRAM. Upon the transfer of the reset data to the SRAM, the system is returned to its pre-transfer cycle condition.

Method and apparatus for resetting a video SRAM

A data load serializer for use in conjunction with a multi-stage, multiple parallel data channel serializer is described. Each data channel of the data serializer preferably includes a data sensing stage and a data latching stage. The serializer is preferably responsive to the provision of an address for selecting data from the main buffer memory for provision to the serial buffer memory and further preferably includes sequencer control logic for receiving the main buffer memory address and for directing the transfer of data between the main and serial buffer memories and an address counter for receiving a start location address referencing a beginning serial data buffer memory location of the storage of data sourced to or from the data serializer. The sequencer control logic provides for the selection of respective data from the serial data buffer for each of the parallel data channels and enables the parallel sensing and latching of the respectively selected data in preparation for sourcing from the data serializer.

Data load sequencer for multiple data line serializer

Multiple bit parallel data serializers are described for accessing data serially through a port at high video data rates. The serializer preferably comprises a buffer array for storing data at a plurality of SRAM memory locations, sense amplifiers for sensing the stored data, an address decoder for selecting a predetermined memory location of the buffer array for data access by the sense amplifiers, a data latch for the latched buffering of data prior to output to the serial port and a control gate for enabling the gated transfer of data between the sense amplifiers and the output latch.

High speed RAM based data serializers

A high speed, low power, multi-bit, single edge triggered, wraparound binary counter is provided which is resettable and loadable from a user-supplied address. The binary counter requires a relatively small amount of power due to the use of CMOS technology for construction of its circuitry, may be initiated at any of 2.sup.N (where N=bit count) start locations, and can be easily adapted to accommodate any desired number of counter cells. Further, it is capable of operating over wide ranges of temperatures and power supply conditions. The high speed binary counter is formed of a plurality of counter cells in which each counter cell includes a pass gate device responsive to a counter-update signal for allowing true and complement addresses to control a switching device when the counter-update signal is in the low state and for isolating the true and complement addresses from the switching device when the counter-update signal is in the high state. Counter-update gating devices are interconnected between a counter pulse signal and each of the counter cells so as to determine which of the counter cells are to receive the counter-update signal so as to change the state of the true and complement addresses.

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Sunnyvale, CA, United States of America

Pradip Banerjee