Path: 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

-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