From: Pete Hatton (pete_at_dynamocomputers.com)
Date: Sun Mar 11 2001 - 21:59:19 EST
Ok here is how it works on an A20P. It should be the same for the A21P since
they both use the ATI Mobility 128 chip. I spent a little time today playing
with display settings under Win98 to see what I could get it to do. I will be
creating a web page with more details on how to set up the different display
modes possible. I will post the address when it is finished.
David Ross wrote:
> This would be very surprising - in general, in an OS with multiple monitor
> support (like W98)
> you either need 2 video cards, or one card with two separate circuits on
> board (like the Matrox twinhead cards) to
> have two independent displays.
Multiple monitor support works on the a20p under Win98 (it also works on a 570),
but not under Win2000. It allows you to use the lcd and an external monitor.
They can be set to different resolutions and color depths. I could not figure
out how to get tv output and lcd at the same time under 98, however you can have
an external monitor and tv simultaneously,with the lcd off.
>
>
> > > > Furthermore, whenever I output to TV, the LCD's resolution drops to
> > 800x600
> > > > or 640x480 256 colors and I have to do a complete reboot (turn
> off/turn
> > on)
> > > > to get the 1600x1200 screen back. Am I missing something ?
>
> This is true for ATI desktop cards too. I think that once a TV is detected,
> and the DAC hardware enabled for
> output to the set, settings are limited to those that won't damage the DAC
> circuitry.
I is a little tricky to get it to switch resolutions without a reboot. First you
must use the ATI icon in the task bar to start display settings. When it is
started this way there will be more settings available then when started the
normal way from the control panel or right-clicking the desktop. Click the
settings tab than the advanced button. On the general tab make sure "apply the
new display settings without restarting" is checked. then go to "ATI Displays"
tab, this is where you can set which display to use. to change the resolution of
the lcd after it has been locked to a lower resolution you have to turn off all
displays but the lcd panel. hit OK to close the advanced setup. This will bring
you back to Display Properties. You will not be able to set it to a higher
resolution yet. the trick is that you must close display properties and reopen
it before you can increase the resolution.
> > You should also be
> > able to have you LCD stay at 1600x1200 resolution while the TV is at
> 800x600.
>
> Again, this would mean that two completely independent sets of rendering are
> taking place, and so would
> need either two video cards or two circuits on the same card.
Well it must have two circuits since it works. The TV out also supports up to
1024x760 (though it is not very clear). If you are not using the multiple
display feature and have it set so that the same thing is displayed on the
external display as on the lcd (like under other Win2000) and the LCD is set at
a higher resolution than the TV or external display is set, the display with
lower resolution will show a portion of the total display area that the mouse
pointer is currently in. The low resolution screen will auto scroll when the
mouse moves out of the area that is currently displayed.
I will have the web page up in a day ot two that will explain all of this
better.
--- Pete Hatton http://www.dynamocomputers.com
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