Computer I/O adapters for programmably varying states of peripheral devices without interfering with central processor operations
US5513368A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1993 |
| Grant date | Apr 30, 1996 |
| Priority date | — |
| Expiry date | Jul 16, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/28
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
DMA adapters which perform programmed data transfer operations in response to descriptors are programmed by information in the same descriptors (and adapter logic responsive to that information) to perform various ancillary control functions relative to addressable I/O devices that conventionally would be addressed and controlled directly by a host (higher level) system processor (e.g., the processor that prepares the descriptors). The ancillary control functions are variable programmably in number (e.g., in the disclosed embodiment, one descriptor can define 0, 1 or 2 discrete ancillary control operations) and effects produced by each operation are programmably variable (e.g., ancillary operation can be used by the adapter to alter states of addressed devices; for example, to prepare a device that has been transferring data in one direction, in a half-duplex mode, for transferring data in the opposite direction, or to switch to a full duplex mode, etc.). These functions hitherto have imposed significant processing burdens on the host processor and functional constraints on the adapters and devices; typically, constraints requiring the adapter and one or more devices to be idled fo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.