On-Screen DisplayControlling the Shuttering EffectPanasonic Semiconductor Development Company MN102H75K/F75K/85K/F85K LSI User Manual194Panasonic7.13 Controlling the Shuttering EffectThe MN102H75K/85K OSD achieves a shuttering effect using four pro-grammable shutters—two vertical and two horizontal. With this feature, you canshutter any portion of the OSD display, or you can combine shuttering with awipe-out effect to create a smooth appearing and disappearing effect.To prevent flickering and shadows on the display, only write to the registersduring the VSYNC cycle.7.13.1 Controlling the Shuttered AreaThe register settings for the two vertical shutters, VSHT0 and VSHT1, and thetwo horizontal shutters, HSHT0 and HSHT1, control which area of the screen isshuttered. Table 7-12 shows the register settings required for this function, andfigure 7-31 shows four setup examples.n Determining the vertical shutter positions (VST0 and VST1)The top edge of the television screen is x’000’. Each integer higher brings theshutter position down one H scan line.n Determining the horizontal shutter positions (HST0 and HST1)The left edge of the television screen is x’000’. Each integer higher brings theshutter position right one pixel. (One pixel, or one dot, is the smallest display unitin the OSD.)Table 7-12 Bit Settings for Controlling the Shuttered AreaFunction VSHT0 Bit VSHT1 Bit HSHT0 Bit HSHT1 Bit DescriptionShutter enable/disable VSON0 VSON1 HSON0 HSON1 0:Disable shutter (Acts as though there are noshutter lines.)1:Enable shutterShutter position VST00–VST09VST10–VST19HST00–HST09HST10–HST19For vertical shutters, this is the number of H scanlines from the top of the screen. For horizontalshutters, it is the number of pixels from the left ofthe screen.Shuttering direction VSP0 VSP1 HSP0 HSP1 0:Shutter below (vertical shutters) or to the right(horizontal shutters)1:Shutter above (vertical shutters) or to the left(horizontal shutters)Shuttering mode control SHTRAD(shared bit)0:AND the shuttered areas of all the shutters1:OR the shuttered areas of all the shutters
