Appendix D

Specifications

CPU and Memory

32-bit CPU

25 MHz system: 80486SX processor,

 

50 MHz system: 80486DX2/50 processor

System speed

25 MHz regardless of CPU; for 80486DX2/50,

 

50 MHz speed is internal only; 8 MHz

 

speed is simulated by inserting wait states;

 

high/low speed selection through

 

software or keyboard command; 0 wait

 

state memory access at high speed

System memory

4MB RAM standard soldered onto the

 

memory card; base memory of either

 

256KB, 512KB, or 640KB, selectable

 

through jumpers; memory expandable

 

using 256KB or 1MB SIMMs up to 16MB

 

(maximum); SIMMs must be 80ns (or

 

faster) access speed

ROM

128KB (includes system and VGA BIOS)

Shadow RAM

0 wait state access speed; automatically

 

copies both ROM BIOS and video ROM

 

into RAM

Math coprocessor

Standard for 50 MHz model; on 25 MHz

 

model, 80486SX microprocessor can be

 

replaced with optional 80487SX chip

Clock/calendar

Real-time clock, calendar, and 50-byte

 

CMOS RAM; battery backup

Cache controller

82385 (25 MHz) standard

Specifications D-1