Atari 2600
The CPU was the MOS Technology 6507, a cut-down version of the 6502, running at 1.19 MHz
The console has only 128 bytes of RAM for run-time data that includes the call stack and the state of the game world.
There is no frame buffer, as the necessary RAM would have been too expensive.
Instead the video device has two bitmapped sprites, two one-pixel "missile" sprites, a one-pixel "ball," and a 40-pixel "playfield" that is drawn by writing a bit pattern for each line into a register just before the television scans that line.
As each line is scanned, a game must identify the non-sprite objects that overlaps the next line, assemble the appropriate bit patterns to draw for those objects, and write the pattern into the register.
In a telling reveal of its Pong heritage, by default, the right side of the screen is a mirrored duplicate of the left; to control it separately, the software may modify the patterns as the scan line is drawn.
After the controller scans the last active line, a more leisurely vertical blanking interval begins, during which the game can process input and update the positions and states of objects in the game world.
Any mistake in timing produces visual artifacts, a problem programmers call racing the beam.
The Atari 2600 uses different color palettes depending on the television signal format used. With the NTSC format, a 128-color palette is available,[29] while in PAL, only 104 colors are available. Additionally, the SECAM palette consists of only 8 colors.