Parallel port with direct memory access capabilities
CA 2027809 A1 · Owner: Jirgal, James J. · Inventors: Jirgal, James J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure, The parallel or printer port in a personal computer can receive data from the memory under the control of the direct memory access (DMA) controller, releasing processor resources. The processor enables the parallel port which, then indicates to the DMA controller the desire to transfer data. A state machine in the parallel port along with associated circuitry, responds to the transfer. of the data to the parallel port and then controls the transfer of the data to the attached device usually a, printer. The state machine causes an interrupt to the processor when the transfer is complete or on receipt of errors from the external device. The state machine also …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 17, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 17, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 17, 2012.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.