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Computer hardware/VGA documents/Q&A.TXT

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+Common Questions.
+
+Q: My S3 or Mach32 card sometimes does weird things.
+A: All 8514/A based cards (S3, ATI Ultra & Mach32) uses I/O addresses like
+   42E8h, BEE8h etc. If you have a Com4 installed (in fact any serial port at
+   2F8h, the serial ports are numbered as they are found in the order 3F8h,
+   2F8h, 3E8h, 2E8h) this will almost certainly cause problems, as most serial
+   and multi I/O adapters only decodes the lower 10 bits of the I/O address.
+   The first check is to run debug and type: d 0:400 and press the enter key.
+   Look at the first 8 two digit/letter combinations, if E8 02 appear here you
+   have a serial port at 2E8h. Start tearing cards out :-)
+   Type Q and press the enter key to leave debug.
+
+
+Q: My video card should be able to do high resolutions and/or high refresh
+   rates, but I can't get them to work.
+A: Many cards can be set up for the type of monitor they are attached to.
+   This setup can be stored in EEPROM, a configuration file or a register.
+   The monitor type is basically how high the line frequency can be.
+   If this is set too high the monitor may not sync, if it is too low the high
+   resolutions and/or high refresh rates may not be available.
+     ATI:      The monitor type is stored in EEPROM. run the install/setup
+               utility
+     Primus:   Run SETCRT n  on startup (n = monitor type)
+     Cirrus:   (54xx) Run CLMODE on startup
+     Tseng:    Run the Vmode/Dmode.. utility on startup
+
+
+Q: I think my video card can do Hi/True color, but it doesn't seem to work
+A: The first requirement for HI/True color is a RAMDAC capable of this.
+   See the section on RAMDACs for names and some programming info.
+   Some cards have BIOSes with Hi/True color modes, but are sometimes shipped
+   with standard RAMDACs. If the RAMDAC is socketed an upgrade may be possible
+   Other cards have Hi/True color RAMDACs, but the BIOS support is shaky or
+   non existing. Check for a BIOS upgrade.
+   Many cards with Hi/True color capability ships with manuals which either
+   doesn't mention this at all or only briefly mentions the possibility.
+   Few, if any BIOSes support read/write pixels, textout or scroll in Hi/True
+   color modes (Ie. only INT 10h AH=00h and 0Fh supported).
+   Run WHATVGA to detect the DAC type, and if any Hi/True color modes are
+   known for your VGA chipset. You may want to inspect the RAMDAC directly, as
+   new types are constantly appearing and may not be detectable yet.
+
+
+Q: What does all this about line frequencies and MHz, kHz and Hz have to do
+   with monitors ??
+A: The dot frequency is the frequency of the pixels sent to the monitor. This
+   is in the MegaHertz (MHz) range.
+   The line frequency is the rate of scanlines sent to the monitor. Each scan
+   line is terminated by a horizontal sync pulse.
+   This is in the kiloHertz (kHz) range.
+   The frame rate is the frequency of images sent to the monitor. Each frame
+   is terminated by a vertical sync pulse.
+   This is in the Hertz (Hz) range.
+   For interlaced displays the frame rate is the rate of half-images (even and
+   odd scanlines are sent in each their own frame), so the rate of the full
+   image is only half the frame rate.
+   Generally:
+      dot freq  = (pixels per line + Hsync time) * line freq
+      line freq = (lines + Vsync time) * frame rate
+   The Hsync and Vsync times indicates the time spent in horizontal and
+   vertical retrace (and any border area). Typically you can use 25%-30% of
+   the pixel number for Hsync and 5%-10% of the line number for Vsync, but
+   this can vary a lot.
+
+   Some typical frequencies:
+   Mode:                     Dot:          Line:         Frame:
+   Text 80x25 (8x14 cell)    25.175 MHz    31.5 kHz      70 Hz
+   Text 80x25 (9x16 cell)    28.322 MHz    31.5 kHz      70 Hz
+   Graphics 640x480          25.175 MHz    31.5 kHz      60 Hz
+   Graphics 800x600          36.000 MHz    34.5 kHz      56 Hz
+           do                50.350 MHz    48.5 kHz      72 Hz
+   Graphics 1024x768         44.900 MHz    35.5 kHz      86 Hz interlaced
+           do                65.000 MHz    48.5 kHz      60 Hz
+           do                80.000 MHz    58   kHz      72 Hz
+   Graphics 1280x1024        80.000 MHz    50.0 kHz      87 Hz interlaced
+           do               105.000 MHz    64   kHz      60 Hz
+
+   The most useful number is the line frequency, this defines what
+   resolutions the monitor can sync to.
+
+
+Q: I have a video card you don't seem to cover, how can I help
+   Or I have some documentation/experience.....
+A: I'm constantly looking for new material and always welcome contributions.
+   If you have original material such as datasheets/books or programmers refs,
+   and don't feel you have the time to enter it all yourself you are very
+   welcome to send a copy of the material to my surface mail address (see the
+   README file for the address). Full credit will of course be given.
+   If you have a video card that WHATVGA fails to identify, identifies more
+   or less incorrectly or fails to use correctly, I'm definitely interested.
+   Please read the WHATVGA.DOC file for some useful tests and ideas.
+   Generally I would recommend running WHATVGA in manual modes first to get a
+   feeling for the program and what works/don't work. Then run WHATVGA /a
+   and mail me the resulting WHVGAxx.TST file (preferably ZIPed or ARJed).
+   Remember to UUencode the file before sending it by E-mail.
+   Also find out as much as possible about your video card (which chipset,
+   which RAMDAC, how much video RAM..) as possible. Remember that many video
+   cards (even brand names) use chipsets from other manufacturers.