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ORCA (REV. B)

I-BUS

ORCA (REV. B)

Processor

CX486/AM486/80486SX/SL80486/80486DX/80486DX4/P24D/P24T

Processor Speed

25/33/40/50(internal)/50/66(internal)100(internal)MHz

Chip Set

OPTI

Video Chip Set

Cirrus Logic

Maximum Onboard Memory

128MB

Maximum Video Memory

2MB

Cache

64/128/256/512KB

BIOS

Unidentified

Dimensions

Unidentified

I/O Options

Floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial ports (2), VGA port

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

IDE interface

J2

Auxiliary keyboard connector

J14

Floppy drive interface

J3

PS/2 mouse port

J21

Parallel port

J4

Reset switch

J22

Serial port 1

J5

Speaker

J25

Serial port 2

J6

Chassis fan power

J26

IDE interface LED

J9

VGA port

J33

USER CONFIGURABLE SETTINGS

Function

Label

Position

 

IDE IRQ14 enabled

J1

Closed

 

IDE IRQ14 disabled

J1

Open

 

IDE read prefetch enabled

J8

Pins 1 & 2 closed

 

IDE read prefetch disabled

J8

Pins 2 & 3 closed

 

IDE type select primary

J11

Pins 1 & 3 closed

 

IDE type select secondary

J11

Pins 3 & 5 closed

 

IDE interface enabled

J11

Pins 2 & 4 closed

 

IDE interface disabled

J11

Pins 4 & 6 closed

Factory configured - do not alter

J12

Open

 

Floppy drive select 1.44MB

J13

Pins 1 & 2 closed

 

Floppy drive select 2.88MB

J13

Pins 3 & 4, 5 & 6 closed

CMOS memory normal operation

J17

Pins 2 & 3 closed

 

CMOS memory clear

J17

Pins 1 & 2 closed

 

PS/2 mouse IRQ12 enabled

J18

Closed

 

PS/2 mouse IRQ12 disabled

J18

Open

 

Password enabled

J19

Closed

 

Password disabled

J19

Open

 

Video IRQ9 enabled

J31

Closed

 

Video IRQ9 disabled

J31

Open

Factory configured - do not alter

J38

Unidentified

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

4MB

(1) 1M x 36

None

None

None

8MB

(1) 2M x 36

None

None

None

8MB

(1) 1M x 36

(1) 1M x 36

None

None

16MB

(1) 4M x 36

None

None

None

16MB

(1) 2M x 36

(1) 2M x 36

None

None

16MB

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

24MB

(1) 2M x 36

(1) 2M x 36

(1) 1M x 36

(1) 1M x 36

32MB

(1) 8M x 36

None

None

None

32MB

(1) 4M x 36

(1) 4M x 36

None

None

32MB

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

40MB

(1) 4M x 36

(1) 4M x 36

(1) 1M x 36

(1) 1M x 36

48MB

(1) 4M x 36

(1) 4M x 36

(1) 2M x 36

(1) 2M x 36

64MB

(1) 8M x 36

(1) 8M x 36

None

None

64MB

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

72MB

(1) 8M x 36

(1) 8M x 36

(1) 1M x 36

(1) 1M x 36

80MB

(1) 8M x 36

(1) 8M x 36

(1) 2M x 36

(1) 2M x 36

96MB

(1) 8M x 36

(1) 8M x 36

(1) 4M x 36

(1) 4M x 36

128MB

(1) 16M x 36

(1) 16M x 36

None

None

128MB

(1) 8M x 36

(1) 8M x 36

(1) 8M x 36

(1) 8M x 36

CACHE CONFIGURATION

Note: Board accepts 64KB/128KB/256KB/512KB cache. The location of banks 0 & 1 is unidentified.

CACHE JUMPER CONFIGURATION

Size

J15

64KB

Open

128KB

Pins 5 & 6 closed

256KB

Pins 3 & 4, 5 & 6 closed

512KB

Pins 1 & 2, 3 & 4, 5 & 6 closed

CACHE BANK CONFIGURATION

Setting

J16

Single bank

Pins 1 & 2 closed

Dual banks

Pins 2 & 3 closed

VIDEO MEMORY CONFIGURATION

Note: Board accepts up to 2MB of video memory. The location and chip sizes are unidentified.

CPU SPEED SELECTION

Speed

J7

J28

25MHz

Pins 1 & 3, 2 & 4 closed

Pins 5 & 6 closed

33MHz

Pins 1 & 3, 4 & 6 closed

Pins 1 & 2, 5 & 6 closed

40MHz

Pins 2 & 4, 3 & 5 closed

Pins 3 & 4, 5 & 6 closed

50iMHz

Pins 1 & 3, 2 & 4 closed

Pins 5 & 6 closed

50MHz

Pins 3 & 5, 4 & 6 closed

Pins 1 & 2, 3 & 4, 5 & 6 closed

66iMHz

Pins 1 & 3, 4 & 6 closed

Pins 1 & 2, 5 & 6 closed

100iMHz

Pins 1 & 3, 4 & 6 closed

Pins 1 & 2, 5 & 6 closed

CPU TYPE SELECTION

Type

J29

J37

Cyrix

Pins 2 & 3 closed

Pins 1 & 2, 3 & 4 closed

AMD

Pins 1 & 2 closed

Open

Intel

Pins 1 & 2 closed

Open

CPU TYPE SELECTION

Type

J36

Intel SX

Pins 2 & 3 closed

Intel DX

Pins 1 & 2, 3 & 4 closed

CPU TYPE SELECTION

Type

J24

SL80486

Pins 1 & 2, 3 & 4 closed

P24T burst

Pins 5 & 6 closed

P24T WB

Pins 7 & 8 closed

P24T WT

Open

CPU TYPE SELECTION

Type

J34

Cyrix

Pins 4 & 6 closed

SL80486

Pins 2 & 4 closed

P24D WB

Pins 3 & 5 closed

P24D WT

Pins 1 & 3 closed

CPU TYPE SELECTION

Type

J35

All CPU types

Pins 1 & 3 closed

P24T only

Pins 3 & 5 closed

Bit 0 to stop clock

Pins 2 & 4 closed

Bit 1 to stop clock

Pins 4 & 6 closed

CPU MULTIPLIER SELECTION

Multiplier

J23

Cyrix CPU

Pins 3 & 4 closed

2x

Pins 3 & 5 closed

2.5x

Pins 1 & 3 closed

3x

Open

CPU FREQUENCY SELECTION

Speed

J27

8MHz

Pins 1 & 2 closed

16MHz (DX4)

Pins 2 & 3 closed

DMA CHANNEL SELECTION

Channel

J32

1

Pins 3 & 4, 5 & 6 closed

3

Pins 1 & 2, 7 & 8 closed

IDE MODE SELECTION

Speed

J10

180ns

Pins 1 & 3, 2 & 4 closed

240ns

Pins 3 & 5, 2 & 4 closed

383ns

Pins 1 & 3, 4 & 6 closed

480ns

Pins 3 & 5, 4 & 6 closed

ON BOARD VIDEO SELECTION

Setting

J30

J39

Enabled

Pins 2 & 3 closed

Closed

Disabled

Pins 1 & 2 closed

Open