See Figure 11-1 for a visual description.
Active Lines Per Frame (ALPF)Defines the number of lines in a frame containing displayable data. ALPF is a subset of the TLPF.
Active Pixels Per Line (APPL)Defines the number of pixel clocks in a line containing displayable data. APPL is a subset of the TPPL.
Horizontal Back Porch (HBP) BlankingDefines the number of blank pixel clocks after the active edge of horizontal sync but before the first active pixel.
Horizontal Front Porch (HFP) BlankingDefines the number of blank pixel clocks after the last active pixel but before horizontal sync.
Horizontal Sync (HS or Hsync)Timing reference point that defines the start of each horizontal interval (line). The active edge of the HS signal defines the absolute reference point. The active edge (either rising or falling edge as defined by the source) is the reference from which all horizontal blanking parameters are measured.
Total Lines Per Frame (TLPF)Total number of active and inactive lines per frame; defines the vertical period (or frame time).
Total Pixel Per Line (TPPL)Total number of active and inactive pixel clocks per line; defines the horizontal line period in pixel clocks.
Vertical Sync (VS or Vsync)Timing reference point that defines the start of the vertical interval (frame). The absolute reference point is defined by the active edge of the VS signal. The active edge (either rising or falling edge as defined by the source) is the reference from which all vertical blanking parameters are measured.
Vertical Back Porch (VBP) BlankingDefines the number of blank lines after the active edge of vertical sync but before the first active line.
Vertical Front Porch (VFP) BlankingDefines the number of blank lines after the last active line but before the active edge of vertical sync.