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Atari coding BBS
| Re: Another STE question |
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Posted by: evil
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May,12.2012-18:24
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Well I can't tell for sure what's going on, BUT the blitter will also delay VBL, just as it delays other interrupts.
An idea is to do the VBL interrupt just as you do the lower border - switch off the blitter first thing, do VBL stuff:
1. Set screen address
2. Set bg colour say $0700 directly after setting screen
3. Start and setup Timer-B as usual from VBL
Here I assume you use Timer-B for rasters (it's hard to know from the few details we have got :)
4. First raster colour, make it $0070 or so
Now, will the top border be red and first raster setting green, without flickers ? Then it seems pretty stable to me.
There is one thing.. If the blitter bus-period begins just before when the VBL starts, maybe the screen address settings will be delayed for too long. I'm not sure how close to the interrupt the registers must be set. One solution to this is to update screen address at say the lower border rout, then you know it will be done long before VBL and it shouldn't be delayed.
However all this also suggests that your rout is not running within 1 VBL, and that's why the blitter pass will go past VBL 1 and delay VBL 2. Hopefully the above thing will help fixing it.
--
Anders Eriksson
ae@dhs.nu
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Date
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Another STE question
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Bod/STAX
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May,10.2012-20:28
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Re: Another STE question
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RA/pdx
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May,11.2012-11:56
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Re: Another STE question
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Bod/STAX
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May,11.2012-13:06
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Re: Another STE question
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Cyprian
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May,11.2012-13:17
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Re: Another STE question
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RA/pdx
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May,11.2012-21:04
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Re: Another STE question
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Bod/STAX
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May,12.2012-12:41
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Re: Another STE question
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evil
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May,12.2012-14:45
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Re: Another STE question
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Bod/STAX
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May,12.2012-17:56
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Re: Another STE question
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evil
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May,12.2012-18:24
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Re: Another STE question
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Bod/STAX
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May,12.2012-21:20
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Re: Another STE question
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evil
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May,13.2012-13:17
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Re: Another STE question
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Frank b
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May,14.2012-20:16
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Re: Another STE question
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Cyprian
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May,13.2012-18:22
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Re: Another STE question
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Patrice Mandin
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May,13.2012-14:38
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Re: Another STE question
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Bod/STAX
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May,15.2012-11:15
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Re: Another STE question
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evil
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May,16.2012-09:17
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Re: Another STE question
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Bod/STAX
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May,16.2012-21:30
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Re: Another STE question
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evil
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May,16.2012-22:40
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Re: Another STE question
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Bod/STAX
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May,17.2012-01:10
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Re: Another STE question
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Klaz
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May,17.2012-14:08
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Re: Another STE question
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Bod/STAX
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May,17.2012-21:35
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Re: Another STE question
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dan/pdx
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May,18.2012-16:03
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Re: Another STE question
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Bod/STAX
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May,18.2012-20:24
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Re: Another STE question
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Bod/STAX
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May,19.2012-16:21
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