Patents by Inventor Charles C. Lai

Charles C. Lai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5511152
    Abstract: A DRAM memory controller for a printer having a single host CPU and a bitmap memory. The CPU initiates data transfers synchronously to a system clock for filling the bitmap memory, and a DMA controller initiates data transfers asynchronously to the system clock for transferring data from the bitmap memory to a print engine. The controller includes a first sequencer for controlling synchronous data transfers initiated by the host CPU, a second sequencer for controlling asynchronous data transfers initiated by the DMA controller, a refresh request generator for generating a refresh request signal which is asynchronous to the system clock, and a third sequencer for controlling memory refresh and for controlling arbtitration betwween the first, second, and third sequencers. Also provided is a method of transferring data between a bitmap memory and a print fifo in a printer.
    Type: Grant
    Filed: September 20, 1993
    Date of Patent: April 23, 1996
    Assignee: Digital Equipment Corporation
    Inventors: Charles C. Lai, Wayne R. Bortman