VGAsovittimet

VGAsovittimet, also known as VGA timings, are a set of parameters that define the timing and synchronization signals for a video graphics array (VGA) display. These timings are crucial for ensuring that the video signal is correctly interpreted by the monitor, resulting in a stable and clear image. The VGA timings include horizontal and vertical synchronization signals, as well as the timing for the active display area and the blanking intervals.

The parameters that make up VGA timings include:

1. Horizontal Total (HT): The total number of pixels in a single horizontal scan line, including the active display area and the blanking intervals.

2. Horizontal Display (HD): The number of pixels in the active display area of a horizontal scan line.

3. Horizontal Front Porch (HFP): The number of pixels in the front porch, which is the period between the end of the active display area and the start of the horizontal synchronization pulse.

4. Horizontal Sync Pulse Width (HSW): The duration of the horizontal synchronization pulse.

5. Horizontal Back Porch (HBP): The number of pixels in the back porch, which is the period between the end of the horizontal synchronization pulse and the start of the next active display area.

6. Vertical Total (VT): The total number of horizontal scan lines in a single frame, including the active display area and the blanking intervals.

7. Vertical Display (VD): The number of horizontal scan lines in the active display area of a frame.

8. Vertical Front Porch (VFP): The number of horizontal scan lines in the vertical front porch, which is the period between the end of the active display area and the start of the vertical synchronization pulse.

9. Vertical Sync Pulse Width (VSW): The duration of the vertical synchronization pulse.

10. Vertical Back Porch (VBP): The number of horizontal scan lines in the vertical back porch, which is the period between the end of the vertical synchronization pulse and the start of the next active display area.

These timings are typically specified in a format known as the "modeline," which includes all the necessary parameters for a specific display resolution and refresh rate. For example, a common modeline for a 640x480 resolution at 60 Hz refresh rate might look like this:

Modeline "640x480" 25.175 640 656 752 800 480 490 492 525

In this modeline, the numbers represent the horizontal total, horizontal display, horizontal front porch, horizontal sync pulse width, horizontal back porch, vertical total, vertical display, vertical front porch, vertical sync pulse width, and vertical back porch, respectively. The first number, 25.175, represents the pixel clock frequency in MHz.

VGAsovittimet are essential for the proper functioning of VGA displays and are used in various applications, including computer monitors, projectors, and other display devices that support the VGA interface.