PAL-Timing scheme for a normal scan line, no sprites on the current scan line but at least the sprites 1+2 active on the following scan line: +---------------------------------------------------------------+ | 1 2 3 4 5 6 | |123456789012345678901234567890123456789012345678901234567890123|Cycles +---------[------(--------------------------------------)---]---+Borders |3-4-5-6-7-rrrrrgggggggggggggggggggggggggggggggggggggggg--0-1s2s|Phi-1 VIC | ssss|Phi-2 VIC |xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxXXX====|Phi-2 CPU +---------------------------------------------------------------+ "-" = idle bus cycle (reads from the last byte of the video bank) <num> = pointer fetch for sprite <num> ; g = graphics fetch s = sprite data fetch ; r = memory refresh cycles x = processor executes instructions (BA high, AEC high) X = bus request pending, bus still available (BA low, AEC high); processor may execute write cycles, stops on the next read cycle. "=" = bus unavailable (BA low, AEC low); processor is blocked because it would like to read something.