Device Control of Interface Signaling Formats Governed by Computer Commands
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
The illustrated system permits a host computer system 1 to communicate with a device 2 in a variety of data transfer formats. The adapter 3, in response to commands from system 1, conducts varied length data transfers between host memory 1A and the device in various bit parallel formats. The adapter operates autonomously through direct access to the host memory to conduct such transfers in a "cycle stealing" mode. An example of a host processor and adapter system capable of such operations would be the IBM Series/1 processor and its "programmable cycle stealing digital input/digital output attachment" (RPQ DO 2288). A microprocessor integrated within the attachment card (adapter) prepares discrete hardware circuits on the card for each cycle stealing transfer process.