








			Information for S3 Chipset Users

			   The XFree86 Project Inc.

				15 January 1996



1.  Supported hardware

The current S3 Server supports the following S3 chipsets: 911, 924, 801/805,
928, 732 (Trio32), 764 (Trio64), 864, 868, 964 and 968.  The S3 server will
also recognise the 866, but it has not been tested with this chipset.  If you
have any problems or success with these, please report it to us.

Nevertheless, this is not enough to support every board using one of these
chipsets. The following list contains some data points on boards that are known
to work.  If your card is similar to one of the described ones, chances are
good it might work for you, too.

      S3 801/805, AT&T 20C490 (or similar) RAMDAC

	       o Orchid Fahrenheit 1280+ VLB

	       o Actix GE32

	    8 and 15/16 bpp

	    Note: Real AT&T20C490 RAMDACs should be automatically detected by
	    the server.  For others which are compatible, you need to provide a
	    `Ramdac "att20c490"' entry in your XF86Config.

	    Real AT&T 20C490 or 20C491 RAMDACs work with the "dac_8_bit"
	    option.  Some clones (like the Winbond 82C490) do not.

	    The Orchid Fahrenheit 1280+ VLB may require `Option "nolinear"'.

      S3 805 VLB, S3 GENDAC (RAMDAC + clock synthesizer)

	       o MIRO 10SD (available for VLB and PCI) It is not known whether
		 all 10SDs use the S3 GENDAC.

	    8 and 15/16 bpp

		  ClockChip "s3gendac"
		  RamDac    "s3gendac"


      S3 801/805, AT&T 20C490 RAMDAC, ICD2061A Clockchip

	       o STB PowerGraph X.24 S3 (ISA)



 Information for S3 Chipset Users





 Information for S3 Chipset Users



	    8 and 15/16 bpp

	    Note: Real AT&T20C490 RAMDACs should be automatically detected by
	    the server.  For others which are compatible, you need to provide a
	    `Ramdac "att20c490"' entry in your XF86Config.

		  ClockChip "icd2061a"
		  RamDac    "att20c490"
		  Option    "dac_8_bit


      S3 805, Diamond SS2410 RAMDAC, ICD2061A Clockchip

	       o Diamond Stealth 24 VLB


	    8 and 15bpp(*) only.

	    requires `Option "nolinear"'

	    (*) The SS2410 RAMDAC is reportedly compatible with the AT&T20C490
	    in 15bpp mode.  To make the server treat it as an AT&T20C490, you
	    need to provide a `Ramdac "att20c490"' entry in your XF86Config.

      S3 801/805, Chrontel 8391 Clockchip/Ramdac

	       o JAX 8241

	       o SPEA Mirage


	    8 and 15/16 bpp.

	    The 8391 is compatible with the AT&T 20C490 RAMDAC

		  ClockChip "ch8391"
		  Ramdac    "ch8391"
		  Option    "dac_8_bit"


      S3 928, AT&T 20C490 RAMDAC

	       o Actix Ultra

	    8 and 15/16 bpp

	    Note: Real AT&T20C490 RAMDACs should be automatically detected by
	    the server.  For others which are compatible, you need to provide a
	    `Ramdac "att20c490"' entry in your XF86Config.  Also, the server's
	    RAMDAC probe reportedly causes problems with some of these boards,
	    and a RamDac entry should be used to avoid the probe.

	    Real AT&T 20C490 or 20C491 RAMDACs work with the "dac_8_bit"
	    option.  Some clones (like the Winbond 82C490) do not.








 Information for S3 Chipset Users



      S3 928, Sierra SC15025 RAMDAC, ICD2061A Clockchip

	       o ELSA Winner 1000 ISA/EISA (``TwinBus'', not Winner1000ISA!!)

	       o ELSA Winner 1000 VL

	    8, 15/16 and 24(32) bpp

	    Supports 8bit/pixel RGB in 8bpp and gamma correction for 15/16 and
	    24bpp modes

	    24 bpp might get ``snowy'' if the clock is near the limit of 30MHz.
	    This is not considered dangerous, but limits the usability of 24
	    bpp.

	    D-step (or below) chips cannot be used with a line width of 1152;
	    hence the most effective mode for a 1 MB board is about 1088x800x8
	    (similar to 2 MB, 1088x800x16).

		  ClockChip "icd2061a"


      S3 928, Bt9485 RAMDAC, ICD2061A Clockchip

	       o STB Pegasus VL

	    8, 15/16 and 24(32) bpp

	    Supports RGB with sync-on-green if "sync_on_green" option is pro-
	    vided and board jumper is set for BNC outputs.

	    VLB linear addressing now occurs at 0x7FCxxxxx so that 64MB or more
	    main memory can be supported without losing linear frame buffer
	    access.

		  ClockChip "icd2061a"
		  Option    "stb_pegasus"


      S3 928, Bt485 RAMDAC, SC11412 Clockchip

	       o SPEA Mercury 2MB VL

	    8, 15/16 and 24(32) bpp

		  ClockChip "SC11412"
		  Option    "SPEA_Mercury"


      S3 928, Bt485 RAMDAC, ICD2061A Clockchip

	       o #9 GXE Level 10, 11, 12










 Information for S3 Chipset Users



	    8, 15/16 and 24(32) bpp

		  ClockChip "icd2061a"
		  Option    "number_nine"


      S3 928, Ti3020 RAMDAC, ICD2061A Clockchip

	       o #9 GXE Level 14, 16

	    8, 15/16 and 24(32) bpp

	    Supports RGB with sync-on-green

		  ClockChip "icd2061a"
		  Option    "number_nine"


      S3 864, AT&T20C498, ICS2494 Clockchip

	       o MIRO 20SD (BIOS 1.xx)

	    The ICS2494 is a fixed frequency clockchip, you have to use X
	    -probeonly (without a Clocks line in XF86Config) to get the correct
	    clock values.

	    8, 15/16 and 24(32) bpp

      S3 864, AT&T20C498 or STG1700 RAMDAC, ICD2061A or ICS9161 Clockchip

	       o Elsa Winner1000PRO VLB

	       o Elsa Winner1000PRO PCI

	       o MIRO 20SD (BIOS 2.xx)

	       o Actix GraphicsENGINE 64 VLB/2MB

	    8, 15/16 and 24(32) bpp

		  ClockChip "icd2061a"


      S3 864, 20C498 or 21C498 RAMDAC, ICS2595 Clockchip

	       o SPEA MirageP64 2MB DRAM  (BIOS 3.xx)

	    8, 15/16 and 24(32) bpp

	    Clockchip support is still sometimes flaky and on some machines
	    problems with the first mode after startup of XF86_S3 or after
	    switching back from VT have been seen; switching to next mode with
	    CTRL+ALT+``KP+'' and back seems to solve this problem.









 Information for S3 Chipset Users



	    Interlaced modes don't work correctly.

	    Mirage P64 with BIOS 4.xx uses the S3 SDAC.

		  ClockChip "ics2595"


      S3 864, S3 86C716 SDAC RAMDAC and Clockchip

	       o Elsa Winner1000PRO

	       o MIRO 20SD (BIOS 3.xx)

	       o SPEA MirageP64 2MB DRAM  (BIOS 4.xx)

	       o Diamond Stealth 64 DRAM

	    8, 15/16 and 24 bpp

      S3 864, ICS5342 RAMDAC and Clockchip

	       o Diamond Stealth 64 DRAM (only some cards)

	    8, 15/16 and 24 bpp

		  ClockChip "ics5342"
		  Ramdac    "ics5342"


      S3 864, AT&T21C498-13 RAMDAC, ICD2061A Clockchip

	       o #9 GXE64 - PCI

	    8, 15/16, 24(32) bpp

		  ClockChip "icd2061a"
		  Option    "number_nine"


      S3 964, AT&T 20C505 RAMDAC, ICD2061A Clockchip

	       o Miro Crystal 20SV

	    8, 15/16, 24(32) bpp

		  ClockChip "icd2061a"
		  Ramdac    "att20c505"


      S3 964, Bt485 RAMDAC, ICD2061A Clockchip

	       o Diamond Stealth 64

	    8, 15/16, 24(32) bpp








 Information for S3 Chipset Users



		  ClockChip "icd2061a"


      S3 964, Bt9485 or AT&T 20C505 RAMDAC, ICS9161a Clockchip

	       o SPEA Mercury 64

	    8, 15/16, 24(32) bpp

		  ClockChip "ics9161a"
		  Option    "SPEA_Mercury"


      S3 964, Ti3020 RAMDAC, ICD2061A Clockchip

	       o Elsa Winner2000PRO PCI

	    8, 15/16, 24(32) bpp

		  ClockChip "icd2061a"


      S3 964, Ti3025 RAMDAC, Ti3025 Clockchip

	       o Miro Crystal 40SV

	       o #9 GXE64 Pro VLB

	       o #9 GXE64 Pro PCI

	    8 bpp, 15, 16 and 24(32) bpp

	    There are some known problems with the GXE64 Pro support, including
	    some image shifting/wrapping at 15/16/24 bpp.

	    We have found that #9 no longer support the GXE64 Pro at 1600x1200.
	    They do however have a new (and more expensive) board called the
	    GXE64Pro-1600 which uses a 220MHz RAMDAC instead of 135MHz part
	    used on the other boards.

      S3 764 (Trio64)

	       o SPEA Mirage P64 (BIOS 5.xx)

	       o Diamond Stealth 64 DRAM

	       o #9 GXE64 Trio64

	    8/15/16/24 bpp

	    Note: The Trio64 has a builtin RAMDAC and clockchip, so the server
	    should work with all Trio64 cards, and there is no need to specify
	    the RAMDAC or clockchip in the XF86Config file.









 Information for S3 Chipset Users



      S3 732 (Trio32)

	       o Diamond Stealth 64 DRAM SE

	    8/15/16/24 bpp

	    Note: The Trio32 has a builtin RAMDAC and clockchip, so the server
	    should work with all Trio32 cards, and there is no need to specify
	    the RAMDAC or clockchip in the XF86Config file.

      S3 868, S3 86C716 SDAC RAMDAC and Clockchip

	       o ELSA Winner 1000AVI

	       o Diamond Stealth Video DRAM

	    8/15/16/24 bpp

      S3 868, AT&T 20C409 RAMDAC and Clockchip

	       o ELSA Winner 1000AVI

	    8/15/16/24 bpp

	    Note: pixelmultiplexing is not supported yet, therefore limited
	    maximum dot clock for 8bpp (currently 67.5MHz, should be changed to
	    100MHz if pixmux isn't fixed prior to release)

      S3 968, Ti3026 RAMDAC, Ti3026 Clockchip

	       o Elsa Winner 2000PRO/X-2 and /X-4 (Revsions <= F)

	       o Elsa Winner 2000AVI-2 and -4

	       o Diamond Stealth 64 VIDEO VRAM

	    8/15/16/24 bpp

      S3 968, Ti3026 RAMDAC, ICS9161A Clockchip

	       o Elsa Winner 2000PRO/X-2 and /X-4 (Revision G)

	    8/15/16/24 bpp

	    Note: clock doubling doesn't work, yet, therefore the maximum
	    usable dot clock is limited to about 120MHz.

      S3 964, IBM RGB 514/524/525/528 RAMDAC & Clockchip

	       o Hercules Graphics Terminator 64

	    8/15/16/24 bpp










 Information for S3 Chipset Users



		  s3RefClk   50
		  DACspeed  170
		  Option  "slow_vram"


      S3 968, IBM RGB 514/524/525/528 RAMDAC & Clockchip

	       o Genoa Genoa VideoBlitz III AV

		       s3RefClk   50
		       DACspeed  170


	       o Hercules Graphics Terminator Pro 64

		       s3RefClk   16
		       DACspeed  220



		 This card may require the line:

			      Invert_VCLK "*" 0



		 in each Display subsection.

	       o STB Velocity 64

		       s3RefClk   24
		       DACspeed  220


	       o Number Nine FX Motion 771

		       s3RefClk   16
		       DACspeed  220



		 This card may require the line:

		       Invert_VCLK "*" 0



		 in each Display subsection.

	       o MIRO 80SV

		       s3RefClk   16
		       DACspeed  250









 Information for S3 Chipset Users



	    8/15/16/24 bpp

      ELSA Winner 2000PRO/X-8 (S3 968, 8MB VRAM, 220MHz for 32bpp)
	    The server has only been tested for "revision C" of this card
	    (guess the serial number should start with C, but not sure since
	    mine says  Ser.No. A-0000.000.000;)  which have an IBM RGB528A note
	    the A;  can't be probed though)

	    depending on the mode line etc there may be some display distor-
	    tions like:

	      1.  many long horizontal lines/stripes

	      2.  pixel jitter or short horizontal stripes like snow all over
		  the screen

	      3.  Like 2., but only when doing graphics ops (like opaque move
		  of windows).

	      4.  additional pixel at the left display edge and some missing
		  pixels at the right edge.

	    All of these problems can be fixed by small adjustments to the mode
	    line (best to run `xvidtune' and make these adjustments interac-
	    tively).  E.g., for the first three problems, shift the display
	    left or right a few steps.	For the last problem, increasing HSyn-
	    cEnd (making the hsync pulse longer) solves the problem.  In some
	    cases, a significant increase in the sync pulse width is needed,
	    and rarely, it needs to be shortened (by decreasing HSyncEnd).

	    In rare cases, InvertVCLK and/or EarlySC may need to be adjusted,
	    followed by an adjustment of BlankDelay (see the bottom line of
	    xvidtune).

	    If you see any of these problems, please contact
	    koenig@XFree86.org, and send details of:

	       o Original mode showing the problem,

	       o Tuned/fixed mode, including all flags from the bottom line of
		 xvidtune,

	       o Colour depth used for this tuned mode line,

	       o Full server startup output.


2.  16bpp and 32bpp

On 801/805 + AT&T490 Cards (like the Fahrenheit 1280+ VLB) only 15 and 16bpp
are supported. 32bpp isn't available on this type of card. (There is a 24 bit
mode under MS Windows, but it's not a 32bpp sparse mode but a real 3
bytes/pixel mode).









 Information for S3 Chipset Users



3.  List of Supported Clock Chips

     ICD2061A				     ==> ClockChip "icd2061a"
     ICS9161A (ICD2061A compatible)	     ==> ClockChip "ics9161a"
     DCS2824-0 (Diamond, ICD2061A comp.)     ==> ClockChip "dcs2824"

     S3 86c708 GENDAC			     ==> ClockChip "s3gendac"
     ICS5300 GENDAC (86c708 compatible)      ==> ClockChip "ics5300"

     S3 86c716 SDAC			     ==> ClockChip "s3_sdac"
     ICS5342 GENDAC			     ==> ClockChip "ics5342"
     STG 1703				     ==> ClockChip "stg1703"

     Sierra SC11412			     ==> ClockChip "sc11412"
     ICS2595				     ==> ClockChip "ics2595"
     TI3025				     ==> ClockChip "ti3025"
     TI3026				     ==> ClockChip "ti3026"
     IBM RGB 5xx			     ==> ClockChip "ibm_rgb5xx"

     Chrontel 8391			     ==> ClockChip "ch8391"

     AT&T 20C409		   ==> ClockChip "att20c409"
     AT&T 20C499 (untested)	   ==> ClockChip "att20c499"


4.  List of Supported RAMDAC Chips

If you have a RAMDAC that is not listed here, be VERY careful not to overdrive
it using XF86_S3. Better contact the XFree86 team first to verify that running
XF86_S3 will not damage your board.

RAMDACs that are grouped together below are treated as compatible with each
other as far as the server is concerned. For example, the server will report
"bt485" when you actually specify RAMDAC "bt9485", or "s3_gendac" when you
specify RAMDAC "ics5300".



























 Information for S3 Chipset Users



     ATT20C409				     ==> RAMDAC "att20c409"

     ATT20C490				     ==> RAMDAC "att20c490"
     ATT20C491				     ==> RAMDAC "att20c491"
     CH8391				     ==> RAMDAC "ch8391"

     ATT20C498				     ==> RAMDAC "att20c498"
     ATT21C498				     ==> RAMDAC "att21c498"

     ATT22C498				     ==> RAMDAC "att22c498"

     ATT20C505				     ==> RAMDAC "att20c505"

     BT485				     ==> RAMDAC "bt485"
     BT9485				     ==> RAMDAC "bt9485"

     IBMRGB514				     ==> RAMDAC "ibm_rgb514"
     IBMRGB525				     ==> RAMDAC "ibm_rgb525"

     IBMRGB524				     ==> RAMDAC "ibm_rgb524"
     IBMRGB526				     ==> RAMDAC "ibm_rgb526"

     IBMRGB528				     ==> RAMDAC "ibm_rgb528"

     S3_GENDAC				     ==> RAMDAC "s3gendac"
     ICS5300				     ==> RAMDAC "ics5300"

     S3_SDAC				     ==> RAMDAC "s3_sdac"
     ICS5342				     ==> RAMDAC "ics5342"

     S3_TRIO32				     ==> RAMDAC "s3_trio32"

     S3_TRIO64				     ==> RAMDAC "s3_trio64"
     S3_TRIO64				     ==> RAMDAC "s3_trio"

     SC11482				     ==> RAMDAC "sc11482"
     SC11483				     ==> RAMDAC "sc11483"
     SC11484				     ==> RAMDAC "sc11484"

     SC11485				     ==> RAMDAC "sc11485"
     SC11487				     ==> RAMDAC "sc11487"
     SC11489				     ==> RAMDAC "sc11489"

     SC15025				     ==> RAMDAC "sc15025"

     STG1700				     ==> RAMDAC "stg1700"

     STG1703				     ==> RAMDAC "stg1703"

     TI3020				     ==> RAMDAC "ti3020"

     TI3025				     ==> RAMDAC "ti3025"

     TI3026				     ==> RAMDAC "ti3026"








 Information for S3 Chipset Users



     None of the above			     ==> RAMDAC "normal"

If you feel adventurous you could also open up your computer and have a peek at
your RAMDAC. The RAMDAC is usually one of the larger chips (second or third
largest chip that is NOT an EPROM) on the board.  The markings on it are usu-
ally

       <Company logo>

	   <company identifier><part number>-<speed grade>
	   <manufacturing week><manufacturing year>
	   <lot number><other funny numbers>

For example:

	       @@
	       @@ AT&T

	     ATT20C490-11
	      9339S ES
	       9869874

This is an AT&T 20C490 with a speed grade of 110 MHz. This would then mean that
you put a `DacSpeed 110' line in your XF86Config file.	Be advised that some
RAMDACs have different modes that have different limits. The manufacturer will
always mark the chip naming the higher limits, so you should be careful.  The
S3 server knows how to handle the limits for most of the RAMDACs it supports
providing the DacSpeed is specified correctly.

Chips labeled -80 or -8  should use `DacSpeed 80' in the device section.

     S3 86C716-ME SDAC	==>  DacSpeed 110
     SC15025-8		==>  DacSpeed  80
     ATT20C490-80	==>  DacSpeed  80

     IBM 8190429	==>  DacSpeed 170
     IBM 03H5428	==>  DacSpeed 170
     IBM 03H6447	==>  DacSpeed 170
     IBM 03H6448	==>  DacSpeed 220
     IBM 03H5319	==>  DacSpeed 220
     IBM 63G9902	==>  DacSpeed 250

     IBM 37RGB514CF17	==>  DacSpeed 170
     IBM 37RGB524CF22	==>  DacSpeed 220
		   ^^


5.  Additional Notes

Note that the Sierra SC1148{5,7,9} will not be distinguished from the Sierra
SC1148{2,3,4} by the probe. The only difference between the two series as far
as the server is concerned is that the {2,3,4} is capable of 15bpp, while the
{5,7,9} is capable of 16bpp. So if you have a SC1148{5,7,9} and want to use
16bpp instead of 15bpp, you will have to specify a RAMDAC "sc11485" line as








 Information for S3 Chipset Users



shown above.

Some RAMDACs (like the Ti3025) require some mode timing consideration for their
hardware cursor to work correctly.  The Ti3025 requires that the mode have a
back porch of at least 80 pixel-clock cycles.  A symptom of this not being cor-
rect is the HW cursor being chopped off when positioned close to the right edge
of the screen.


6.  Reference clock value for IBM RGB 5xx  RAMDACs

Cards with IBM RGB5xx RAMDACs use several different input frequencies for the
clock synthesizer which can't be probed without some knowledge of the text mode
clocks (which may be a wrong assumption if you're using non-standard text
modes).  Here is the procedure you should use to find out the input frequency:

First run

	 X -probeonly >& outfile

and check the output for the probed clock chip which might look like this:

     (--) S3: Using IBM RGB52x programmable clock (MCLK 66.000 MHz)
     (--) S3: with refclock 16.000 MHz (probed 15.952 & 16.041)
			    ^^^^^^	^^^^^^^^^^^^^^^^^^^^^^

there will be a "good guessed" value which will be used and two probed values
in brackets based on the 25MHz and 28MHz text clocks. This probing can only
work if you run a normal 80x25 or 80x28 text mode!

The refclock values known so far are:

	  STB Velocity 64	   24 Mhz
	  Genoa VideoBlitz II AV   50 MHz
	  Hercules S3 964     50 MHz
	  Hercules S3 968     16 MHz
	  #9 Motion 771       16 MHz

depending on the quartz on your card and maybe other features like an addi-
tional clock chip on the Genoa card (which as a 14.3MHz quartz).

If you claim that your card has a 16MHz clock, but it really uses 50MHz, all
pixel clocks will be tripled and a 640x480 mode with 25MHz will use a 75MHz
pixel clock, so be very careful.

If you found the right refclock, you should set it in the config file (device
section) e.g. with

	  s3RefClk  16



or









 Information for S3 Chipset Users



	  s3RefClk  50


so that that this value will be used even if you use another text mode and
probing fails!


7.  How to avoid ``snowing'' display while performing graphics operations

For cards with the S3 Vision864 chip, there is an automatic correction which
depends on the pixel clock and the memory clock MCLK at which the S3 chip oper-
ates. For most clock chips this value can't be read (only the S3 SDAC allows
reading the MCLK value so far), so this value has to be estimated and specified
by the user (the default is 60 [MHz]).

With the new `s3MCLK' entry for your XF86Config file, now you can specify e.g.

      s3MCLK 55


for a 55 MHz MCLK which will reduce snowing. Smaller MCLK values will reduce
performance a bit so you shouldn't use a too low value (55 or 50 should be a
good guess in most cases).

Below is a small shell script which might be useful to determine the approxi-
mate value for MCLK (about +/- 1-2 MHz error). Before running this script you
have to add the line

      s3MNadjust -31 255


to the device section in your XF86Config file and restart X Windows.  With this
option (which is for testing and debugging only) you'll get lots of disastrous
display flickering and snowing, so it should be removed again immediately after
running the test script below.

Running this script will use xbench and/or x11perf to run a test to determine
the MLCK value, which is printed in MHz. Up to 4 tests are run, so you'll get
up to 4 estimates (where the first might be the most accurate one).























 Information for S3 Chipset Users



     #!/bin/sh

     exec 2> /dev/null

     scale=2

     calc() {
       m=`awk 'BEGIN{printf "%.'$scale'f\n",'"( $1 + $2 ) / $3; exit}" `
       [ -z "$m" ] && m=` echo "scale=$scale; ( $1 + $2 ) / $3" | bc `
       [ -z "$m" ] && m=` echo "$scale $1 $2 + $3 / pq" | dc `
       echo $m
     }

     run_xbench() {
       r=` ( echo 1; echo 2; echo 3; echo 4 ) | xbench -only $1 | grep rate `
       [ -z "$r" ] && return
       cp="$2 $3"
       set $r
       calc $3 $cp
     }

     run_x11perf() {
       r=` x11perf $1 | grep trep | tr '(/)' '	 ' `
       [ -z "$r" ] && return
       cp="$2 $3"
       set $r
       calc `calc 1000 0 $4` $cp
     }

     run_x11perf "-rect500 -rop GXxor"	   3.86  5.53  #  0 1  #    4.11    5.52  #
     run_xbench invrects500		   4.63  5.48  #  0 1  #    4.69    5.48  #

     run_x11perf "-rect500 -rop GXcopy"  -16.42 13.90  #  0 1  #  -14.99   13.88  #
     run_xbench fillrects500		  -7.81 13.57  #  0 1  #   -8.53   13.58  #

     exit

     Generated from XFree86: xc/programs/Xserver/hw/xfree86/doc/sgml/S3.sgml,v 3.37.2.1 1997/05/27 06:22:23 dawes Exp $





     $XConsortium: S3.sgml /main/14 1996/02/21 17:45:58 kaleb $


















 Information for S3 Chipset Users





































































				   CONTENTS



1. Supported hardware ....................................................... 1

2. 16bpp and 32bpp .......................................................... 9

3. List of Supported Clock Chips ........................................... 10

4. List of Supported RAMDAC Chips .......................................... 10

5. Additional Notes ........................................................ 12

6. Reference clock value for IBM RGB 5xx  RAMDACs .......................... 13

7. How to avoid ``snowing'' display while performing graphics operations ... 14







































				       i


