Direct Memory Access (DMA).html (1424B)
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 <html><head><link rel="stylesheet" href="sitewide.css" /><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/><meta name="exporter-version" content="Evernote Mac 6.13.1 (455785)"/><meta name="altitude" content="-0.3009934425354004"/><meta name="author" content="Alex Balgavy"/><meta name="created" content="2017-12-17 6:30:53 PM +0000"/><meta name="latitude" content="52.37361692187181"/><meta name="longitude" content="4.836262575463552"/><meta name="source" content="desktop.mac"/><meta name="updated" content="2017-12-17 6:36:01 PM +0000"/><title>Direct Memory Access (DMA)</title></head><body><div>A special control unit to manage the transfer of blocks directly between main memory and devices</div><div>does functions normally carried out by processor when accessing main memory</div><div>its operation is under control of an operating system routine, but transfers data without intervention</div><div><br/></div><div>to transfer a block of words:</div><div><ol><li>Processor sends to DMA controller: starting address, num of words in block, direction of transfer</li><li>DMA controller performs requested operation</li><li>When complete, informs processor by raising an interrupt</li></ol><div><br/></div></div><div><br/></div></body></html>