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Article #2226Re: Bus Latency
From: dougp
Date: Sun, 19 Nov 1989 04:01
Date: Sun, 19 Nov 1989 04:01
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1117 bytes
-Message-Text-Follows- In article <128061@sun.Eng.Sun.COM>, cmcmanis%pepper@Sun.COM (Chuck McManis) writes... >Given a 704 X 440 screen with some sprites, audio, copper and blitter >activity I'm pretty sure it is possible to lock out DMA for one full frame, >14mS at 60Hz. > Frame time = 16.6 mS but chip activity is concentrated during > the (220lines/frame)/(60 frames/second * 262.5 max lines/frame) > which equals 13.9 mS. > >--Chuck McManis Given the 704x440 screen and the other conditions, how does the buss arbitraion handle the condition of the 68000 wanting access to chip ram, and the DMA wanting access to fast ram? does the bus lock up until the chip ram is free preventing the DMA from accessing fast ram or is there some more intelegent arbitration going on? Douglas Peale
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!aplcen!samsung!usc!ucsd!hub!dougp From: dougp@voodoo.ucsb.edu Newsgroups: comp.sys.amiga.tech Subject: Re: Bus Latency Message-ID: <3058@hub.UUCP> Date: 19 Nov 89 04:01:53 GMT Sender: news@hub.UUCP Organization: UC, Santa Barbara. Physics Computer Services Lines: 18