Acer V55LA-2 User manual

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System Board
System Board 1-1
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 match
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. Two DRAM banks composed of four 72-pin sockets come with
the board to support single- and double-density SIMMs for a maximum
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 second-
level cache.
The system board includes a 188-pin connector for 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 transfer
rate support up to four IDE devices. Onboard I/O interfaces comprise
of two UART 16550 serial ports, a parallel port with ECP/EPP feature,
and PS/2 keyboard and mouse ports.

1-2 User’s Guide
1.1 Major Features
The system board has the following major features:
•A zero-insertion force (ZIF) socket for 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 sockets
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

System Board 1-3
1.1.1 System 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 1-1 System Board Layout

1-4 User’s Guide
1.1.2 Slot Boards
The system board comes with a slot board already installed. The slot
board carries the PCI and ISA bus slots for system enhancements 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 1-2 2-PCI/3-ISA Slot Board (for Aspire desktop systems)
Figure 1-3 3-PCI/4-ISA Slot Board
(for Aspire minitower systems)

System Board 1-5
1.2 Jumpers and Connectors
1.2.1 Jumper and Connector Locations
Figure 1-4 shows the jumper and connector locations on the system
board.
Figure 1-4 System Board Jumper and Connector Locations
The blackened pin of a jumper represents
pin 1.

1-6 User’s Guide
1.2.2 Jumper Settings
Table 1-1 lists the system board jumpers with their corresponding
settings and functions.
Table 1-1 System Board Jumper Settings
Jumper Setting Function
BIOS Type
JP1 1-2
2-3 For models with Acer BIOS For models with OEM BIOS
LED Function
JP2 1-2
2-3 LED for IDE and FDD LED for IDE only
Second-level Cache
JP3, JP4 1-2, 1-2
1-2, 2-3
2-3, 2-3
256 KB
512 KB
1 MB
Regulator
JP7 Closed
Open For single-voltage CPUs (P54C, K5, M1) For dual-voltage CPUs (P55C, K6, M2)
SMM/Reset Switch
JP11 1-2
2-3 CN19 pins 19-20 support SMM switch Reserved
Software Shutdown
JP16 1-2
2-3 UPS enabled UPS disabled
CPU Voltage
JP43 (for I/O)
JP44 (for core)
1-2
2-3
1-2
2-3
3.5V
3.3V
3.2V
2.8V

System Board 1-7
Tables 1-2 to 1-4 show the settings of DIP switch 2 (SW2), JP7, JP43,
and JP44 for CPU selection.
Table 1-2 SW2, JP7, JP43, and JP44 Settings
CPU Freq.
(MHz) Host Bus Freq. (MHz) SW1 SW2 SW3 SW4 JP7 JP43 JP44
Intel P54C
P75 50 On On Off Off Closed 2-3 2-3
P90 60 On Off Off Off Closed 2-3 2-3
P100 66 Off On Off Off Closed 2-3 2-3
P120 60 On Off On Off Closed 2-3 2-3
P133 66 Off On On Off Closed 2-3 2-3
P150 60 On Off On On Closed 2-3 2-3
P166 66 Off On On On Closed 2-3 2-3
P200 66 Off On Off On Closed 2-3 2-3
Intel P55C
P150 60 On Off On On Open 2-3 2-3
P166 66 Off On On On Open 2-3 2-3
P200 66 Off On Off On Open 2-3 2-3
Cyrix M1 (6x86)
P120+ 50 On On On Off Closed 2-3 2-3
P150+ 60 On Off On Off Closed 2-3 2-3
P166+ 66 Off On On Off Closed 2-3 2-3
Cyrix M1 (6x86L)
P120+ 50 On On On Off Open 2-3 2-3
P150+ 60 On Off On Off Open 2-3 2-3
P166+ 66 Off On On Off Open 2-3 2-3
Cyrix M2
PR166 66 Off On On On Open 2-3 2-3
PR180 60 On Off Off On Open 2-3 2-3
PR200 66 Off On Off On Open 2-3 2-3

1-8 User’s Guide
Table 1-2 SW2, JP7, JP43, and JP44 Settings (continued)
CPU Freq.
(MHz) Host Bus Freq. (MHz) SW1 SW2 SW3 SW4 JP7 JP43 JP44
AMD K5
PR75 50 On On Off Off Closed 1-2 2-3
PR90 60 On Off Off Off Closed 1-2 2-3
PR100 66 Off On Off Off Closed 1-2 2-3
PR120 60 On Off On Off Closed 1-2 2-3
PR133 66 Off On On Off Closed 1-2 2-3
PR166 66 Off On On On Closed 1-2 2-3
AMD K6
PR166 66 Off On On On Open 2-3 1-2
PR200 66 Off On Off On Open 2-3 1-2
PR233 66 Off On Off Off Open 2-3 1-2
Table 1-3 SW2 Settings (Onboard Sound Chip)
Setting 5 Function
ON Onboard sound chip disabled
OFF Onboard sound chip enabled
Table 1-4 SW2 Settings (Password Security)
Setting 6 Function
ON Password bypass
OFF Password check

System Board 1-9
1.2.3 Connector Functions
Table 1-5 lists the different connectors on the system board and their
respective functions.
Table 1-5 Connector Functions
Connector Function
CN1 Feature connector for multimedia or
Ethernet solution
CN2 CD-audio line-in connector
CN3 Power connector
CN5 USB connector
CN6 WaveTable connector
CN7 PS/2 keyboard connector
CN8 PS/2 mouse connector
CN9 Audio I/O board connector
CN10 Diskette drive connector
CN11 IDE connector 2
CN12 IDE connector 1
CN13 Serial port 1
CN14 Serial port 2
CN17 Parallel port
CN18 CPU fan connector
CN19 Multifunction connector
CN21 Video port
CN22 Fax/modem connector
CN23 ATI multimedia connector

1-10 User’s Guide
Table 1-5 Connector Functions (continued)
Connector Function
CN31 Internal line-in connector
JP48 Hard disk and message LED (pins 1-3-5)
Power LED (pins 2-4-6)
JP50 Power-on switch connector
JP15 Standby power connector
JP30 External battery connector
See section 1.10.1 for details on power and LED cables to the
connector JP48.
1.3 ESD Precautions
Always observe the following electrostatic discharge (ESD)
precautions before installing a system component:
1. Do not remove a component from its antistatic packaging until
you are ready to install it.
2. Wear a wrist grounding strap before handling electronic
components. Wrist grounding straps are available at most
electronic component stores.
Do not attempt the procedures described in
the following sections unless you are a
qualified technician.