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