Subject: RE: [stella] 262 scanline kernel is rolling From: Chris Wilkson <ecwilkso@xxxxxxx> Date: Sat, 26 Mar 2005 22:15:40 -0500 |
Oh. Well, good for z26! :) So...with that in mind, things should look like this: (pictures helps me to not get confuzzled) line 258: active video line 259: active video line 260: VBLANK line 261: VBLANK line 262: VBLANK line 001: VBLANK VSYNC line 002: VBLANK VSYNC line 003: VBLANK VSYNC line 004: VBLANK line 005: VBLANK line 006: VBLANK line 007: VBLANK line 008: VBLANK line 009: VBLANK line 010: VBLANK line 011: VBLANK line 012: VBLANK line 013: VBLANK line 014: VBLANK line 015: VBLANK line 016: VBLANK line 017: VBLANK line 018: active video line 009: active video ... ... -Chris On Sat, 26 Mar 2005, Zach M wrote: > Ok, I misunderstood before. > > FYI, I've been refering to lines by their number starting at 1, not 0, > because that's how the z26 trace log does it. > > >From: Chris Wilkson <ecwilkso@xxxxxxx> > >Reply-To: stella@xxxxxxxxxxxxxxxxxx > >To: <stella@xxxxxxxxxxxxxxxxxx> > >Subject: RE: [stella] 262 scanline kernel is rolling > >Date: Sat, 26 Mar 2005 21:17:50 -0500 > > > >Wait... > > > >What I meant was you should turn on VSYNC 3 lines after you turn on VBLANK. > >So when are you turning on VSYNC? Assuming you're numbering your lines so > >that the first line of VSYNC is line 0, (that's what most of the docs > >around > >here say to do) then you should turn on VBLANK at the beginning of line > >259. > >It would then be on for lines 259, 260, and 261. Then VSYNC comes on at > >the > >beginning of line 0 (= line 262) and turns off at the beginning of line 3. > > > >Is this equivilent to what you meant? > > > >-Chris > > > >On Sat, 26 Mar 2005, Zach M wrote: > > > > > I just tested a few minutes ago, and the screen does not roll anymore. I > >had > > > made the changes Dennis suggested, and also turned on VBLANK at line 261 > >as > > > Chris had recommended. So it is hard to say exactly what the problem > >was. > > > The reason I suspect it had something to do with writing 8 to VBLANK is > > > because an earlier version of the kernel did not roll, and there #$42 > >was > > > written to VBLANK (just like in"Our First Kernel"). The "lda #$42" line > > > before "sta VBLANK" was inadvertenly removed at some point. > > > > > > I might do more experiments with writing 8 to VBLANK if there is enough > > > interest. > > > > > > >From: "Dennis Debro" <dennis@xxxxxxxxxxxxxxx> > > > >Reply-To: stella@xxxxxxxxxxxxxxxxxx > > > >To: <stella@xxxxxxxxxxxxxxxxxx> > > > >Subject: RE: [stella] 262 scanline kernel is rolling > > > >Date: Sat, 26 Mar 2005 14:49:35 -0500 > > > > > > > >Hi there, > > > > > > > > > Right now you're writing 0 at the start of vertical blank > > > > > and 8 at the start of overscan. > > > > > > > >That is strange. As Thomas said, D1 of VBLANK only controls the TIA > >output. > > > >At least as documented by the programming manual. So writing 8 to the > > > >register is essentially the same as writing 0 (i.e. enabling TIA > >output). > > > > > > > >I don't have my hardware setup at the moment to play with this. Was > >this > > > >truly the problem? What happens if you used other values or ignored > >VBLANK > > > >altogether? By the values you were entering this should have been > > > >simulated. > > > >Are there other bits used by VBLANK that we don't know about? > > > > > > > >Take care, > > > >Dennis > > > > > > _________________________________________________________________ > > > Dont just search. Find. Check out the new MSN Search! > > > http://search.msn.click-url.com/go/onm00200636ave/direct/01/ > > > > > > > > > Archives (includes files) at > >http://www.biglist.com/lists/stella/archives/ > > > Unsub & more at http://stella.biglist.com > > > > > > > > > > > >Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > >Unsub & more at http://stella.biglist.com > > > > _________________________________________________________________ > FREE pop-up blocking with the new MSN Toolbar get it now! > http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/ > > > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > Unsub & more at http://stella.biglist.com > > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://stella.biglist.com
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