The V55LA-2 is a high-performance system board with a 64-bit
architecture. It supports the Intel P54C and P55C CPUs running at
75/90/100/120/133/150/166/200 MHz. It also supports Cyrix M1/M2
and AMD K5/K6 CPUs. The system board utilizes the Peripheral
Component Interconnect (PCI) local bus architecture that maximizes
the system performance by enabling high-speed peripherals to matc h
the speed of the microprocessor with its 120 MB or 132 MB per
second transfer rate in burst mode.
The board incorporates a Sound Blaster Pro-compatible audio
subsystem that consists of CD-audio, WaveTable, and fax/modem
line-in interfaces.
A standard 1-MB video DRAM comes onboard and is upgradable up to
2 MB. T wo DRAM banks compos ed of four 72-pin s ockets com e with
the board to support single- and double-density SIMMs for a m aximum
system memory of 128 MB. The SIMM sockets accommodate both
the standard page mode and extended data output (EDO) type
SIMMs. The board supports 256-KB or 512- KB pipeline burst sec ondlevel cache.
The system board includes a 188-pin connector f or the slot board that
contains the PCI and ISA bus slots. The two onboard PCI- enhanced
IDE interfaces with a zero-wait state and 16.6 MB per second trans fer
rate support up to four IDE devices. Onboar d I/O interfaces c omprise
of two UART 16550 serial ports, a parallel port with ECP/EPP feature,
and PS/2 keyboard and mouse ports.
System Board1-1
1.1Major Features
The system board has the following major features:
A zero-insertion force (ZIF) sock et f or Intel P54C and P55C, Cyrix
•
M1/M2, or AMD K5/K6
Two DRAM banks composed of four 72-pin SIMM sockets that
•
support 4/8/16/32-MB 60/70ns SIMMs
256-KB or 512-KB write-back pipeline burst second-level cache
•
(manufacturing option)
256-KB boot block mode Flash ROM for system BIOS, VGA
•
BIOS, and PnP ESCD
Two PCI-enhanced IDE interfaces that support up to four IDE
•
devices
System clock/calendar with 256-byte CMOS RAM
•
Interfaces for CD-audio, fax/voice modem, and WaveTable
•
support
Standard 1-MB video DRAM onboard plus two upgrade sock ets
•
for up to 2-MB video memory
188-pin connector for PCI/ISA slot board
•
Feature socket for multimedia or Ethernet solution
•
External ports:
•
PS/2 keyboard and mouse ports
•
Two buffered high-speed serial ports
•
One ECP/EPP high-speed parallel port
•
Video port
•
1-2User’s Guide
1.1.1System Board
Figure 1-1 shows the locations of the system board major
components.
1 Battery
2 Tag SRAM
3 Pipeline burst second-level cache
4 Pentium CPU socket
5 CPU voltage regulators
6 SIMM sockets
7 Buzzer
8 Switch 2 (SW2)
9 Video RAM upgrade sockets
10 Video RAM
11 Video port
12 Parallel port
13 BIOS
14 Serial port 2
15 Slot board connector
16 Serial port 1
17 Mouse port
18 Keyboard port
19 USB connector
Figure 1-1System Board Layout
System Board1-3
1.1.2Slot Boards
The system board comes with a slot board already installed. The slot
board carries the PCI and ISA bus slots for system enhanc ements and
future expansion.
The slot board may vary in size and layout depending on your system
housing. Figures 1-2 and 1-3 show the two kinds of slot boards.
Figure 1-22 -PCI/3-ISA Slot Board (f or Aspire desktop systems)
Figure 1-33-PCI/4-ISA Slot Board
(for Aspire minitower systems)
1-4User’s Guide
1.2Jumpers and Connectors
1.2.1Jumper and Connector Locations
Figure 1-4 shows the jumper and connector locations on the s ystem
board.
Figure 1-4System Board Jumper and Connector Locations
The blackened pin of a jumper represents
pin 1.
System Board1-5
1.2.2Jumper Settings
Table 1-1 lists the system board jumpers with their corresponding
settings and functions.
Table 1-1System Board Jumper Settings
JumperSettingFunction
BIOS Type
JP11-2
LED Function
JP21-2
Second-level Cache
JP3, JP41-2, 1-2
Regulator
JP7Closed
SMM/Reset Switch
JP111-2
Software Shutdown
JP161-2
CPU Voltage
JP43 (for I/O)
JP44 (for core)
2-3
2-3
1-2, 2-3
2-3, 2-3
Open
2-3
2-3
1-2
2-3
1-2
2-3
For models with Acer BIOS
For models with OEM BIOS
LED for IDE and FDD
LED for IDE only
256 KB
512 KB
1 MB
For single-voltage CPUs (P54C, K5, M1)
For dual-voltage CPUs (P55C, K6, M2)
CN19 pins 19-20 support SMM switch
Reserved
UPS enabled
UPS disabled
3.5V
3.3V
3.2V
2.8V
1-6User’s Guide
Tables 1-2 to 1-4 show the settings of DIP switch 2 (SW 2), JP7, J P43,
and JP44 for CPU selection.