[comp.sys.amiga] Another problem with A2320 in overscan area

sdl@linus.mitre.org (Steven D. Litvinchouk) (12/10/90)

> The Commodore A2320 Display Enhancer card WILL automatically adjust to
> either PAL or NTSC display mode and give you severe overscan support in
> both modes i.e. 768x489 in NTSC mode and 768x576 in PAL mode

I just installed my new A2320 card in my Amiga 2000, and connected it
to my new NEC Multisync 2A monitor.

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.

This is true no matter which Amiga screen I am displaying--Workbench,
a custom VT100 emulator screen, AegisDraw 2000, etc.  In fact, it's
even true for the blank screen I initially see on bootup.

Can this be corrected with the coarse or fine tuning adjustment, or
might this be a problem with my monitor?  Failing that, is there some
way to *stop* displaying output in the overscan area?  I'd rather not
see overscan at all if the color is going to be off there.  Thanx in
advance!


-- 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?"

hood@cbmvax.commodore.com (Scott Hood) (12/11/90)

In article <SDL.90Dec9131817@lyra.linus.mitre.org> sdl@linus.mitre.org (Steven D. Litvinchouk) writes:
>
>> The Commodore A2320 Display Enhancer card WILL automatically adjust to
>> either PAL or NTSC display mode and give you severe overscan support in
>> both modes i.e. 768x489 in NTSC mode and 768x576 in PAL mode
>
>I just installed my new A2320 card in my Amiga 2000, and connected it
>to my new NEC Multisync 2A monitor.
>
>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.
>
>This is true no matter which Amiga screen I am displaying--Workbench,
>a custom VT100 emulator screen, AegisDraw 2000, etc.  In fact, it's
>even true for the blank screen I initially see on bootup.
>
>Can this be corrected with the coarse or fine tuning adjustment, or
>might this be a problem with my monitor?  Failing that, is there some
>way to *stop* displaying output in the overscan area?  I'd rather not
>see overscan at all if the color is going to be off there.  Thanx in
>advance!
>
>
>-- 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?"

Steven,

Sometimes, due to the monitor, if the display is adjusted to far to
either the left or the right the monitor does brighten or even darken
the display.  I have noticed this with other monitors as well.  You may
try to adjust the monitors' horizontal position control to move the
display to reduce this effect and then use the `preferances' position
adjustment control to center the amiga's display on the monitor.

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!" 

CJC105@psuvm.psu.edu (12/12/90)

In article <SDL.90Dec9131817@lyra.linus.mitre.org>, 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

hood@cbmvax.commodore.com (Scott Hood) (12/14/90)

In article <90345.212323CJC105@psuvm.psu.edu> CJC105@psuvm.psu.edu writes:
>In article <SDL.90Dec9131817@lyra.linus.mitre.org>, 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!" 

sdl@linus.mitre.org (Steven D. Litvinchouk) (12/14/90)

In article <90345.212323CJC105@psuvm.psu.edu> CJC105@psuvm.psu.edu writes:

> >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.
>
> 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.

It's the monitor all right; I found that I could have my monitor
adjusted to minimize this problem.  Thanx to you and to all others who
responded to my call for help.

> 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. 

I noticed this too.  I have used my monitor's horizontal positioning
control to move this artifact off the screen.

--
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?"

jim@syteke.be (Jim Sanchez) (12/14/90)

I wish I could adjust my size control sufficiently to fill the
physical screen with a raster.  Does anyone know if a "Redmond Cable"
is required with the NEC 3D and the A2320.  I know I had to get a
buffered cable for the NEC to use it with the stock 2000.
-- 
Jim Sanchez          | jim@syteke.be (PREFERRED)
Hughes LAN Systems   | OR uunet!mcsun!ub4b!syteke!jim 
Brussels Belgium     | OR jim@hls.com
-- 
Jim Sanchez          | jim@syteke.be (PREFERRED)
Hughes LAN Systems   | OR uunet!mcsun!ub4b!syteke!jim 
Brussels Belgium     | OR jim@hls.com

rmm20@ccc.amdahl.com (Robert Mitchell) (12/16/90)

In article <1727@syteke.be> jim@syteke.be (Jim Sanchez) writes:
>I wish I could adjust my size control sufficiently to fill the
>physical screen with a raster.  Does anyone know if a "Redmond Cable"
>is required with the NEC 3D and the A2320.  I know I had to get a
>buffered cable for the NEC to use it with the stock 2000.
>-- 
>Jim Sanchez          | jim@syteke.be (PREFERRED)
>Hughes LAN Systems   | OR uunet!mcsun!ub4b!syteke!jim 
>Brussels Belgium     | OR jim@hls.com
>-- 
>Jim Sanchez          | jim@syteke.be (PREFERRED)
>Hughes LAN Systems   | OR uunet!mcsun!ub4b!syteke!jim 
>Brussels Belgium     | OR jim@hls.com

Just a note: I am looking at a NEC 3D screen as I write this.
It is on a "stock" 2000.
All I did was wire up a liitle cross-wire adapter to go from
the NEC to the DB23 on the 2000.  No logic; just wires.
Works great.-- 
UUCP:  rmm20@juts.ccc.amdahl.com
DDD:   408-746-8491
USPS:  Amdahl Corp.  M/S 205,  1250 E. Arques Av,  Sunnyvale, CA 94086
BIX:   bobmitchell

billy@phoenix.pub.uu.oz.au (Jeff Coleman) (12/19/90)

In <00gj02a.04B501@JUTS.ccc.amdahl.com> rmm20@ccc.amdahl.com (Robert Mitchell) writes:

>In article <1727@syteke.be> jim@syteke.be (Jim Sanchez) writes:
>>I wish I could adjust my size control sufficiently to fill the
>>physical screen with a raster.  Does anyone know if a "Redmond Cable"
>>is required with the NEC 3D and the A2320.  I know I had to get a
>>buffered cable for the NEC to use it with the stock 2000.
>>-- 
>>Jim Sanchez          | jim@syteke.be (PREFERRED)
>>Hughes LAN Systems   | OR uunet!mcsun!ub4b!syteke!jim 
>>Brussels Belgium     | OR jim@hls.com
>>-- 
>>Jim Sanchez          | jim@syteke.be (PREFERRED)
>>Hughes LAN Systems   | OR uunet!mcsun!ub4b!syteke!jim 
>>Brussels Belgium     | OR jim@hls.com

>Just a note: I am looking at a NEC 3D screen as I write this.
>It is on a "stock" 2000.
>All I did was wire up a liitle cross-wire adapter to go from
>the NEC to the DB23 on the 2000.  No logic; just wires.
>Works great.-- 
>UUCP:  rmm20@juts.ccc.amdahl.com
>DDD:   408-746-8491
>USPS:  Amdahl Corp.  M/S 205,  1250 E. Arques Av,  Sunnyvale, CA 94086
>BIX:   bobmitchell

Just for later Reference could you list the wireouts from the 3D -> db23

thanx
 
Jeff Coleman

-------------------------------------------------------------------------------
| Jeff Coleman [ Billy ]     |	             " (2B || !2B) ? :; "             |
| billy@phoenix.pub.uu.oz.au |       "ok so it don't look so good visually !" |
-------------------------------------------------------------------------------