APPENDIX THREE
Atari Timing Values
clock frequency = 1.79 MHZ
1 machine cycle = 0.558 usec.
1 frame         = 1/60 second
scan lines      = 262/frame
color clocks    = 228/scan line
color clocks    = 2/machine cycle
machine cycles  = 29868/frame
machine cycles  = 114/scan line

VBLANK time = 7980 machine cycles or less, depending on
GRAPHICS mode. The shortest 6502 instruction requires two cycles;
during that time the electron beam moves four color clocks.

Horizontal blank time:
Wide playfield    18 machine cycles
Normal playfield  34 machine cycles
Narrow playfield  50 machine cycles

See the Hardware Manual for more information on cycle counting.