I have implemented a VGA controller in FPGA, for 800x600 resolution @60Hz. Can I use it to drive a PC monitor ? In the PC's monitor resolution settings, it's seen that it supports multiple resolution at different frame rates, including 800x600. The maximum is 1024x768. Its an LCD monitor. Will the PC's monitor automatically "figure out" the intended resolution and frame rate from the Hsync and Vsync signal of my VGA controller, and display it in full screen?

  • \$\begingroup\$ I can't speak for everyone here, but I certainly know that I don't have the documentation for the monitor in front of me... \$\endgroup\$ Nov 8, 2017 at 13:04
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    \$\begingroup\$ You could answer your own question in about 5 seconds by simply plugging in your monitor... \$\endgroup\$ Nov 8, 2017 at 13:16
  • \$\begingroup\$ Ha yea lol when I get the PC tomo. I was just looking for an intuitive answer before that. \$\endgroup\$
    – Mitu Raj
    Nov 8, 2017 at 13:18
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    \$\begingroup\$ Most monitors auto-detect the input resolution because that's what the old CRT standards did. Or more accurately, the signals themselves are what drive the display directly based on time and synchs. However, 800 by 600 is a very old format and may not be supported or look great on a newer monitor. \$\endgroup\$
    – Trevor_G
    Nov 8, 2017 at 13:35
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    \$\begingroup\$ I have done this before. It worked. With older CRT and newer LCD monitors. \$\endgroup\$
    – Eugene Sh.
    Nov 8, 2017 at 14:37

1 Answer 1


Your monitor should auto-detect the resolution. You can eventually double-check this by hooking it to a PC with a VGA output, and force the screen resolution to 800x600. You'll see that the monitor will scale the image.

This scaling is done by the monitor, not by the video card. There is a "scaler chip" inside TFT monitors that takes care of that. More details can be found on the internet.

  • \$\begingroup\$ When i plugged vga cable and switched on the PC's LCD monitor. It seems to detect hsync and vsync signals correctly. It flashed : current settings - 800x600 @60 Hz . But the screen is blank with no image. What is the problem ? Is there anyother signal other than sync and RGB to drive LCD monitor ? Voltage from DAC display driver IC is around 0 -3.3 V. Are these voltage levels not enough ? I changed and checked with all polarities of hsync and vsync. Still no change. \$\endgroup\$
    – Mitu Raj
    Nov 15, 2017 at 14:54
  • \$\begingroup\$ @MITU VGA levels are much lower, it seems: microvga.com/faq/electrical/what-are-vga-voltage-levels \$\endgroup\$
    – dim
    Nov 15, 2017 at 14:59

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