Like Atari's other XL and XE computers, the Atari 1200XL requires a "Memory Management Unit" or MMU. This is reproduction of Atari's 1200XL MMU for which the part number is C060609 and it is installed in socket U14 on the system board.

This part differs from the "standard" 600XL and 800XL MMU in that the 1200XL has 2 ROM chips. Because of these 2 ROM chips, a slightly different MMU is required in order to handle them.

This part is made from a custom programmed programmable logic chip, the ATF16V8B.

The first picture shows the chip by itself and the second picture shows the chip installed in the system board of an Atari 1200XL. (Atari 1200XL system board not included, of course.)