FREDDIE is the name for a 40-pin large scale integrated circuit found in later model
Atari 8-bit computers. It is a
RAM address
multiplexer, used for
DRAM access. Atari created this chip to replace several other chips to cut costs and to enhance CPU and
ANTIC memory access.
FREDDIE, combined with a C061618
MMU (XL/XE) and C025953
EMMU (130XE) allows the CPU and ANTIC to access memory independently of each other. Originally designed for the cancelled 1400XL and 1450XLD, it was eventually used in the 800XLF (labelled "800XL," refers to European version), 65XE, 130XE, and XEGS.
External links
atarimuseum.comFreddie MCU Engineering Data (PDF file)
Freddie info and diagram
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FREDDIE, Atari