Sbus graphic cards, resolutions, monitors
Trying to run an IBM TFT 15" monitor with
1024x768@75Hz with my Ultra-2 and
SBus graphic cards GX or TXplus,
I learned the following:
GX, GXplus with Bt458 DAC only support
the following resolutions:
1152 x 900 @ 66 Hz
1152 x 900 @ 76 Hz
1024 x 800 (!) @ 84 Hz (!)
The last value is something, most TFTs
cannot support, be it with the No. of
lines (800) or more often, the high
refresh frequency of 84 Hz. :-(
Most native resolution of TFT monitors
is 1024 x 768 @ 60 Hz.
With the TGX+ SBus card (Bt 467 DAC), the
choice of resolutions and/or refresh rates rises:
1152 x 900 @ 66 Hz
1152 x 900 @ 76 Hz
1024 x 800 (!) @ 84 Hz (!)
1024 x 768 @ 60 Hz (here it is!)
1024 x 768 @ 70 Hz
1024 x 768 @ 76 Hz (works well with most IBM TFTs)
1280 x 1024 @ 67 Hz
1280 x 1024 @ 76 Hz (should work with 19" TFTs)
1600 x 1280 @ 76 Hz
1920 x 1080 @ 72 Hz
So, if you have a TGX+ card available, you
should be able to find the matching resolution
and refresh rate for the most common monitors,
be it CRTs or TFTs.
The setting is easily done inside the Open
Boot PROM (OBP):
setenv output-device screen:r1152x900x76
for example.
My debian 2.6.18-6-sparc64-smp runs the correct
settings of OBP, but screen resolution shows
always the right chosen resolution with a very
wrong refresh rate of 30915 Hz (ooops!).
BTW: this link from Brian brought me on the right
track:
More info can be found here:
http://mediacast.sun.com/users/Barton808/media/Sbus_cgsix_graphics_cards800-5114-10.pdf
(read only pages 1-10, 1-11 for sense pin, 9-7 for
GX cards, 9-22 for TGX+ cards) :-)
I hope this will help others with their
monitor settings.
Regards,
Norbert
--
IBG Ingenieurbüro Gerhards
Dipl.-Ing. Norbert Gerhards
Laurentiusstr. 16 - 20
52072 Aachen
Tel. 0241-705 08-14
Fax 0241-705 08-99
mobil 0172-240 66 36
email n.gerhards@ib-gerhards.de
URL www.ib-gerhards.de
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