ANTIC's updates on even scan lines shifting the bit pattern of individual Players and Missiles down one scan line. - Single line resolution. A new DMA fetch and Player/Missile register update occurs on every scan line. CTIA/GTIA register VDELAY (D01Chex/53276dec) masking the updates on even scan lines reduces Single line Player/Missile resolution to appear to be Double line resolution, though the data is shifted one scan line lower. CTIA/GTIA must also be specifically enabled to receive the Player/Missile graphics data via DMA to correctly present the objects on screen. See CTIA/GTIA's GRACTL register for more information. The location of memory read by ANTIC for Player/Missile graphics is controlled by register PMBASE. This value of PMBASE provides the starting page of the base address for Player/Missile graphics. When double line resolution P/M graphics are operating the PMBASE value must begin on a 1K boundary. When single line resolution P/M graphics are operating the PMBASE value must begin on a 2K boundary. The memory maps for the Player/Missile graphics modes: Double line resolution (1 byte per 2 scanlines, 128 bytes each object) relative to PMBASE x hex/256dec: Single line resolution (1 byte per scanline, 256 bytes each object) relative to PMBASE x hex/256dec: Missiles share the same bytes of the memory maps above, two bits per Missile: ANTIC does not use the first and last 8 scan lines worth of data of Player/Missile memory in the memory map. In double line resolution the first and last four bytes are ignored, in single line resolution the first and last eight bytes. Since the Player/Missiles are an overlay independent from Playfield graphics and are rendered in the overscan area the vertical coordinates for Player/Missile data must be offset to align objects with the Playfield. In the Operating System's 192-scan line default graphics modes the Player/Missile vertical data coordinates are offset from the Player/Missile's start in memory as shown below. Overscan entries show the first and last used offsets of Player/Missile data: Limitations The vertical extent of the entire Playfield display varies between 0 and 240 scanlines - this depends on the number of lines ANTIC is programmed to display according to the Display List. ANTIC begins generating scan lines at TV scan line 8 continuing to line 247 for a total of 240 scan lines. The horizontal width of the Playfield display may be set to 256, 320 or 384 pixels wide corresponding to