Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!uunet!cbmvax!hood From: hood@cbmvax.commodore.com (Scott Hood) Newsgroups: comp.sys.amiga Subject: Re: Another problem with A2320 in overscan area Message-ID: <16500@cbmvax.commodore.com> Date: 13 Dec 90 17:32:43 GMT References: <90345.212323CJC105@psuvm.psu.edu> Reply-To: hood@cbmvax.commodore.com (Scott Hood) Organization: Commodore, West Chester, PA Lines: 71 In article <90345.212323CJC105@psuvm.psu.edu> CJC105@psuvm.psu.edu writes: >In article , sdl@linus.mitre.org (Steven >D. Litvinchouk) says: >> >>The card works as advertised, but I notice a few annoying artifacts. >>In addition to the "single-pixel-flicker" that has been mentioned on >>this newsgroup, I have found that in the left severe overscan area of >>the screen (that is, the very left 1/4 inch of the illuminated display >>area), the background color is off--it appears to be somewhat lighter >>than the background color of the entire rest of the screen. >> > > >>-- steven litvintchouk >>-- >>Steven Litvintchouk >>MITRE Corporation >>Burlington Road >>Bedford, MA 01730 >>(617)271-7753 >>ARPA: sdl@mbunix.mitre.org >>UUCP: ...{att,decvax,genrad,necntc,ll-xn,philabs,utzoo}!linus!sdl >> "Where does he get those wonderful toys?" > > >It might be that your horizontal size knob on your monitor is adjusted too wide >and part of the CRT beam is bouncing off the side of the CRT tube and causing >a band of light color. > > >On another note: > >One strange problem I noticed is when the 2320 is de-interlacing, the odd and >even fields don't line up on the right hand side of the screen. I.E the HSYNC >pulse takes a little longer on the even field for one frame, then it takes >longer on the odd field for the next. This creates a vertical rolling effect >of pixels on the right hand side. And, when any part of my pointer touches this >area the entire pointer starts this rolling effect! > >It takes about 8 seconds for any particular pixel to travel up the screen. > >Hmm... 470 lines * 1/60 sec = 7.8 seconds = appox 8 seconds. I wonder >whats going on here! > >------------------------------------------------------------------------------- > Chris Conrad > > CJC105@psuvm You my friend have discovered the infamous non-ECS denise chip bug. The old Denise chip has the blanking on the right-hand border wrong by one low-res pixel (140nS) which was fixed in the ECS Denise chip. I On other display cards (i.e. FlickerFixer) which limit the maximum overscan you do not see this denise artifact because it is to far in the overscan area. If you hook up your multisync monitor to the normal 15Khz DB23 port on the Amiga and adjust the monitor so that you can see black borders all the way around, you will see that this artifact is there. Note that this appears only in NTSC modes, either interlaced or non-interlaced display modes. It is possible for the display enhancer to not display this artifact and thus not be noticable, but that would require modification to the gate array logic. This is being looked at.. Regards, Scott Hood -- -- Scott Hood, Hardware Design Engineer (A3000 Crew), Commodore-Amiga, Inc. {uunet|pyramid|rutgers}!cbmvax!hood hood@cbmvax.cbm.commodore.com "The views expressed here are not necessarily those of my employer!"