System Board Layout - Acer 486 User Manual

1.1

System Board Layout

The system board has the following major components:
486SX, SX2, DX2, or DX4 series CPU
4-MB onboard RAM expandable to 36 MB
Two 72-pin SIMM sockets for memory upgrade
128-KB ROM for system BIOS and VGA BIOS
120-pin connector for ISA riser card
System clock/calendar
Two 9-pin serial ports
One 25-pin Centronics parallel port
PS/2-compatible keyboard and mouse interface
512-KB or 1-MB DRAM for onboard local bus VGA interface;
expandable to 1 MB (for GD-5424) or 2 MB (for GD5429)
Embedded fixed disk interface
Upgradable cache memory (128-KB or 256-KB)
Optional enhanced IDE interface
Optional power daughter board that enables the system to
support the 3.3V microprocessors
Figure 1-1 shows the board layout and the locations of the important
components.
1-2 User's Guide