Subject: Re: [stella] PAL VSYNC timings?? From: Dennis Debro <ddebro@xxxxxxxxxxxxx> Date: Tue, 19 Nov 2002 7:06:29 -0500 |
Hi Eric, > Curious, Skeleton cycles it's PRNG and does some other things during VSYNC. > Maybe a look at the Solaris & Desert Falcon disassembly might provide some > hints. I ran Solaris and Desert Falcon through Z26 to get a read out. Solaris: VSYNC stops on scan line 4 at cycle count 14. It also does not do 3 WSYNC lines. The last line of the vertical sync is done by instructions taking longer than 76 cycles on the previous line. Desert Falcon: VSYNC stops on scan line 3 at cycle count 2. > My guess (based upon the NTSC docs I've seen) is enabling VSYNC causes the > TIA to output the serration pulses (NTSC lines 4,5 & 6) which are low except > for two pulses in the middle & end of the line. > > If this is true, then VSYNC needs to be enabled & disabled during the > horizontal sync pulse period of the line. So, as long as you do the STA > VSYNC immediately after the STA WSYNC (and don't hit RSYNC while VSYNC is > enabled) you should be okay. I guess we need to find other games that tend to roll to further test your theory. Does anyone know of any others besides Solaris and Desert Falcon? Take care, Dennis ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
Current Thread |
---|
|
<- Previous | Index | Next -> |
---|---|---|
Re: [stella] PAL VSYNC timings??, Dennis Debro | Thread | Re: [stella] PAL VSYNC timings??, Thomas Jentzsch |
Re: [stella] Star Fire: Meteor Danc, Dennis Debro | Date | Re: [stella] PAL VSYNC timings??, Thomas Jentzsch |
Month |