The three odd-numbered bitplanes (1, 3, and 5) are grouped together by the hardware and may be used in playfield 1. Likewise, the three even-numbered bitplanes (2, 4, and 6) are grouped together and may be used in playfield 2. The bitplanes are assigned alternately to each playfield, as shown in Figure 3-13. About dual-playfield bitplanes. ------------------------------- In high resolution mode, you can have up to two bitplanes in each playfield -- bitplanes 1 and 3 in playfield 1 and bitplanes 2 and 4 in playfield 2. Number of Bitplanes "turned on." Plafield 1 * Playfield 2 * ------------------------------------------------------ 0 none none ____________ | | 1 | 1 | | | |____________| ____________ ____________ | | | | 2 | 1 | | 2 | | | | | |____________| |____________| ____________ ____________ | | | | 3 | 1 _________|__ | 2 | | | | | | |__| 3 | |____________| | | |____________| ____________ ____________ | | | | 4 | 1 _________|__ | 2 _________|__ | | | | | | |__| 3 | |__| 4 | | | | | |____________| |____________| ____________ ____________ | | | | 5 | 1 _________|__ | 2 _________|__ | | | | | | |__| 3 _________|__ |__| 4 | | | | | | |__| 5 | |____________| | | |____________| ____________ ____________ | | | | 6 | 1 _________|__ | 2 _________|__ | | | | | | |__| 3 _________|__ |__| 4 _________|__ | | | | | | |__| 5 | |__| 6 | | | | | |____________| |____________| * Note: Either playfield may be placed "in front of" or "behind" the other using the "swap-bit." Figure 3-13: How Bitplanes Are Assigned to Dual Playfields
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