FREDDIE was the name for a 40-pin LSI found in Atari 8-bit computers. It is a RAM address multiplexer

Multiplexer

In electronics, a multiplexer is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n select lines, which are used to select which input line to send to the output...

, used for DRAM

Dynamic random access memory

Dynamic random-access memory is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1...

 access. Atari created this chip to replace several other chips to cut costs and to enhance CPU and ANTIC

ANTIC

Alphanumeric Television Interface Controller is an early video system chip used in the Atari 8-bit family of microcomputers as well as the Atari 5200 in the 1980s. The chip was patented by Atari, Inc. in 1981...

 memory access.

FREDDIE, combined with a C061618 MMU

Atari MMU

The Atari MMU is a custom MMU chip for the Atari 8-bit computers. It enables access to the hardware registers on ANTIC, GTIA, POKEY and 6520 PIA....

 (XL/XE) and C025953 EMMU

EMMU

EMMU is a custom MMU chip for the 130XE Atari 8-bit computer. It's used to access the extra 64kB of RAM present in the 130XE.The user cannot directly manipulate the EMMU, but selects the various ROMS and memory banks via the memory-mapped hardware register known as PORTB...

(130XE) allowed the CPU and ANTIC to access memory independently of each other.

Originally designed for the 1400XL and 1450XLD, it was eventually used in the XE series of Atari computers.

Found in the following machines:

• 800XLF (labeled '800XL', refers to European version)
• 65XE
• 130XE
• 800XE
• XEGS

External links

• atarimuseum.com Freddie MCU Engineering Data (PDF file)
• jindroush site(archived) Freddie info and diagram