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CT60 and related things BBS
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Posted by: Instream
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May,13.2012-10:40
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Good question :)
The short answer:
Yes, the 060 runs in parallel with the (super-)blitter, as long as the 060 does not access the SV graphics RAM. So working in the CT60 SDRAM is totally free. Writing to ST-RAM however, will generate a write to the SV grapics RAM too, since the SV snoops all ST-RAM writes for compatibility. Such accesses can hinder the superblitter for a few cycles.
The long answer:
On the falcon030 the blitter runs on the same bus as the 030, and thus it must "steal" cycles from the CPU to get the work done.
But in the SuperVidel FPGA, the "superblitter" (SB) runs on a different clock domain (and bus). It is the same as the DDR2 SDRAM controller, today at 185MHz. The 060 is connected to this bus via a data bridge, which makes the two buses completely independent of each other. The 060 only affects the DDR2 bus during writes and reads of 060 data to/from the DDR2 SDRAM. At all other times the DDR2 bus is free for the SB and the DVI and VGA pipelines (and the CT60 bus is free for the 060). These three units are the only ones that compete for bandwidth on the DDR2 bus. The SB has the lowest priority of these three since the video pipelines naturally need to get data to display on the screen within a certain time.
The SB optionally can generate an interrupt to the 060 when a blitting operation is done. This way you can keep long blitter lists, and let the 060 do other stuff while the blitter works, instead of continuously poll the Done-flag.
There is an overview document on nature.atari.org which shows how the different buses are connected and what units are on each bus.
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Topic
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Posted by
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Date
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SuperVidel demo #6
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Instream
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May,12.2012-21:08
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Re: SuperVidel demo #6
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CiH
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May,12.2012-23:38
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Re: SuperVidel demo #6
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Instream
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May,12.2012-23:45
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Re: SuperVidel demo #6
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evil
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May,13.2012-08:34
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Re: SuperVidel demo #6
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Instream
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May,13.2012-10:40
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Re: SuperVidel demo #6
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evil
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May,13.2012-11:11
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Re: SuperVidel demo #6
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ggn
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May,13.2012-13:40
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Re: SuperVidel demo #6
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ggn
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May,13.2012-13:42
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Re: SuperVidel demo #6
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FDR1980
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May,15.2012-23:23
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Re: SuperVidel demo #6
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ggn
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May,16.2012-07:33
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Re: SuperVidel demo #6
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evil
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May,16.2012-22:43
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Re: SuperVidel demo #6
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ggn
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May,17.2012-11:58
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Re: SuperVidel demo #6
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FDR1980
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May,17.2012-22:56
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Re: SuperVidel demo #6
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Beetle
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May,29.2012-18:15
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Re: SuperVidel demo #6
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mac-falcon
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May,14.2012-11:03
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What's the anti-troll code?
That's your personal code to be able to add comments and messages on the dhs.nu site.
Don't have a code or forgot it? Fix it here.
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