Specifications

1–1
CHAPTER 1
INTRODUCTION
1.1 GENERAL DESCRIPTION
The Little Board/486i is an exceptionally high integration, high performance 486DX-based PC/AT
compatible system in the footprint of a 5 1/4 inch disk drive. This rugged and high quality single-board
system contains all the component subsystems of a PC/AT motherboard plus the equivalent of six PC/AT
expansion boards.
Key functions included on the Little Board/486i are CPU, RAM, embedded-PC BIOS, keyboard and
speaker interfaces, four buffered serial ports, a multimode IEEE-1284-compliant parallel port, floppy and
local-bus IDE drive controllers, a flat panel/CRT display interface, a SCSI-II controller, and an Ethernet
LAN interface. In addition, the Little Board/486i includes a comprehensive set of system extensions and
enhancements that are specifically designed for embedded systems. Furthermore, it is designed to meet
the size, power consumption, temperature range, quality, and reliability demands of embedded
applications.
Among the many embedded-PC enhancements that ensure fail-safe embedded system operation are a
watchdog timer, a powerfail NMI generator, and an onboard bootable "solid state disk" (SSD) capability.
System operation requires a single +5 Volt power source and offers "green PC" power-saving modes
under support of advanced power management (APM) BIOS functions.
1.2 FEATURES
CPU/Motherboard
The Little Board/486i has a fully PC-compatible motherboard architecture. Versions with CPUs running
66 Mhz, 100 Mhz, and 133 Mhz are available. The 486 CPU has an 16K byte on-chip cache memory
which can be configured as ‘Write-Back’ or ‘Write-Through’.
The board uses standard 72-pin Single In-line Memory Module (SIMM™) memory modules, and supports
memory from 4M bytes to 64M bytes.
It has a full complement of standard PC/AT architectural features, including DMA channels, interrupt
controllers, real-time clock, and timer counters.
Enhanced Embedded-PC BIOS
One of the most valuable features of the Little Board/486i is its enhanced embedded-PC BIOS, which
includes an extensive set of functions that meet the unique requirements of embedded system applications.
These enhancements include:
! Solid State Disk (SSD) support (see below)
! SCSI services—full SCSI BIOS services are integrated with hard disk support
! Watchdog timer—monitors boot process; provides function call for applications
! Fast boot operation—normal or accelerated POST
! Fail-safe boot support—intelligently retries boot devices until successful
! Battery-free boot support—saves system SETUP information in non-volatile EEPROM
! Serial console option—lets you use a serial device as console