Processor local bus posted DMA FlyBy burst transfers

US6055584A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Jeffrey Todd Bridges · Raleigh, US
• Edward Hammond Green, III · Cary, US
• Richard Gerard Hofmann · Cary, US
• David Otero · Cary, US
• Mark Michael Schaffer · Cary, US
• Dennis Charles Wilkerson · Durham, US

Key dates

• Filing date: Nov 20, 1997
• Grant date: Apr 25, 2000
• Expiry date: Nov 20, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F13/28
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A method and implementing system are provided which includes a DMA controller coupled to a slave bus controller through a processor local bus. The slave bus controller is also coupled to a memory unit. The memory unit is connected directly to a peripheral device. The DMA controller is arranged to receive a data transfer request from the peripheral unit and initiate a transfer cycle with the slave bus controller. The slave bus controller is selectively operable to assert a transfer signal to the memory unit which enables data movement directly between memory and the peripheral device in accordance with the request from the peripheral device. Upon completion of the address transfer and prior to the completion of the data transfer, the slave bus controller generates a transfer complete signal back to the peripheral device. This technique allows for a DMA FlyBy transfer to be overlapped with a subsequent processor local bus transfer.