IBM CORPORATION

PERSONAL SYSTEM/2 HMM

Processor

80486SX/80486DX/80486DX2/80486DX4/P24T

Processor Speed

25/33/50(internal/66(internal)/75(internal)/100(internal)/MHz

Chip Set

Unidentified

Video Chip Set

None

Maximum Onboard Memory

Unidentified

Maximum Video Memory

None

Cache

128/256KB

BIOS

Unidentified

Dimensions

254mm x 218mm

I/O Options

32-bit PCI slots (3), floppy drive interface, IDE interfaces (2), parallel port, PS/2 mouse port, serial ports (2)

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

PS/2 mouse port

J2

IDE interface 1

J21

Speaker

J5

IDE interface 2

J22

Parallel port

J8

32-bit PCI slots

PC1 – PC3

Floppy drive interface

J9

Power LED

W12

Serial port 2

J10

IDE interface LED (PCI)

W39

Serial port 1

J11

IDE interface LED (ISA)

W46

USER CONFIGURABLE SETTINGS

Function

Label

Position

»

Secondary cache write select write back

W1

Pins 2 & 3 closed

 

Secondary cache write select write through

W1

Pins 1 & 2 closed

»

Internal cache write select write through

W4

Open

 

Internal cache write select write back

W4

Closed

»

Flash BIOS normal operation

W6

Pins 2 & 3 closed

 

Flash BIOS recovery mode

W6

Pins 1 & 2 closed

»

Factory configured - do not alter

W8

Closed

»

PS/2 mouse installed

W10

Closed

 

PS/2 mouse not installed

W10

Open

 

Parity generation select DPU

W17

Pins 1 & 2 closed

 

Parity generation select CPU

W17

Pins 2 & 3 closed

»

DPU does not force parity

W18

Pins 2 & 3 closed

 

DPU forces parity

W18

Pins 1 & 2 closed

»

Factory configured - do not alter

W19

Closed

»

Cache installed

W21

Open

 

Cache not installed

W21

Closed

DRAM CONFIGURATION

Note: The maximum size and configuration is unidentified.

CACHE CONFIGURATION

Note: The location and configuration is unidentified.

CACHE JUMPER SELECTION

Size

W5

W22

W23

128KB

Open

Closed

Open

256KB

Closed

Open

Closed

CACHE TAG SELECTION

Size

W24

W26

 

7-bit

Open

Closed

 

8-bit

Closed

Closed

»

9-bit

Closed

Open

CPU SPEED SELECTION

Speed

W16

W20

25MHz

Open

Closed

33MHz

Closed

Open

50iMHz

Open

Closed

66iMHz

Closed

Open

75iMHz

Open

Closed

100iMHz

Closed

Open

CPU TYPE SELECTION

Type

W2

W3

80486SX

Pins 2 & 3 closed

Closed

80486DX

Pins 1 & 2, 3 & 4 closed

Closed

80486DX2

Pins 1 & 2, 3 & 4 closed

Closed

80486DX4

Pins 1 & 2, 3 & 4 closed

Closed

P24T

Pins 1 & 2, 3 & 4 closed

Open

CPU MULTIPLIER SELECTION

Multiplier

W33

1x

Pins 1 & 2 closed

2x

Pins 2 & 3 closed

3x

Open

DMA CHANNEL SELECTION

Channel

W43

»

ISA IDE used P10 transfer

Open

 

6

Pins 1 & 2 closed

 

7

Pins 2 & 3 closed

ISA IDE IRQ SELECTION

IRQ

W42

IRQ14

Pins 1 & 2 closed

IRQ15

Pins 2 & 3 closed

PCI IDE IRQ SELECTION

IRQ

W35

W38

»

IRQ14

Closed

Open

 

IRQ15

Open

Closed

PCI INTERRUPT SELECTION

Setting

W37

INTR_A enabled

Closed

INTR_A disabled

Open

PCI COMPLIANT IRQ SELECTION

IRQ

J101

IRQ1

Pin 2

IRQ3

Pin 3

IRQ4

Pin 4

IRQ5

Pin 5

IRQ6

Pin 6

IRQ7

Pin 7

IRQ8

Pin 8

IRQ9

Pin 9

IRQ10

Pin 10

IRQ11

Pin 11

IRQ12

Pin 12

IRQ14

Pin 13

IRQ15

Pin 14