Fairchild > Fairchild3850PK
Modified: May 25, 2005, 3:05 am
Data Code:7901
Architecture:8 bit
Used in:Computers and Military Apps.
Description:Fairchild F8 or 3850 is a multi-chip
microcontroller. The F8 is based on the 3850
chip - this chip integrates 8-bit ALU, 64-bytes
scratchpad RAM and two 8-bit I/O ports. The 3850
does not decode instructions - 3851 or 3856
program storage unit (PSU) chips, dynamic memory
interface (DMI) chip, 3853 static memory
interface (SMI) chip or 3861/3871 parallel I/O
(PIO) chips are used for this task. If necessary,
multiple PSU, DMI, SMI and PIO chips can be used
together with one 3850 ALU chip. The PSU chips
include the following on-chip features:

ROM: 1 KB for the 3851 and 2 KB for the 3856
Memory addressing logic

Two 8-bit I/O ports
Interrupt logic
SMI, DMI and PIO chips don't have on-chip ROM.

One-chip implementation of F8, Mostek 3870, was
released in 1977.

The F8 was used in the company's Channel F
Fairchild Video Entertainment System in 1976. By
the end of the decade, Fairchild played mostly in
niche markets, including the "hardened" IC market
for military and space applications, and in Cray
supercomputers. Fairchild was acquired by
National Semiconductor in the 1980s, and spun off
again as an independent company in 1997.