Apparatus and method for performing look-ahead scheduling of DMA transfers of data from a host memory to a transmit buffer memory
US5970229A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1996 |
| Grant date | Oct 19, 1999 |
| Priority date | — |
| Expiry date | Sep 12, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/387
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for transferring data from a source memory (e.g. a host memory) to a peripheral interface via a bus utilizes a transmit buffer memory coupled to the peripheral interface, and a current time counter advancing at the rate at which data is to be transferred from the transmit buffer memory to the peripheral interface. A schedule table data structure stores entries in some or all of its locations, where each location corresponds to a point in time at which data is to be transferred from the transmit buffer memory to the peripheral interface. A schedule table pointer is used for pointing to successive locations in the schedule table. The schedule table pointer advances at a rate faster than the current time counter advances so that the schedule table pointer represents a point in time which is ahead of the point in time currently output by the current time counter. A data transfer is initiated from the source memory to the transmit buffer memory via the bus when a valid entry is stored at the location in the schedule table pointed to by the schedule table pointer. The data is then transferred out of the transmit buffer memory to the peripheral interface when the c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.