Apple 250 manual Terminator

Page 23

C H A P T E R 2

Hardware Modifications

Table 2-4 lists and describes the interface signals for the 8-pin segment of the connector.

Table 2-4

Hard disk SCSI connector signal assignments: SCSI ID

 

 

 

Pin

Signal name

Description

1, 2, 3, 4, 8

Unused

These pins are not used and are not connected

 

 

electrically to the CPU

5

/ID1

SCSI ID 1

6

/ID2

SCSI ID 2

7

/ID4

SCSI ID 4

The internal hard disk is assigned a SCSI ID number (0–7). Pins 5-7 on the SCSI connector are encoded and allow the CPU to select the appropriate device. Table 2-5 shows how the ID signals are encoded.

Table 2-5

SCSI ID encoding

 

 

 

 

 

ID1: Pin 5

ID2: Pin 6

ID4: Pin 7

SCSI ID

High

High

High

0

Low

High

High

1

High

Low

High

2

Low

Low

High

3

High

High

Low

4

Low

High

Low

5

High

Low

Low

6

Low

Low

Low

7

Terminator

The hard disk has 1000-ohm termination resistors for all I/O signal lines. The lines are pulled up to through the resistors to termination power.

200 MB Hard Disk Drive

13

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Contents PowerBook Duo Limited Warranty on Media and Replacement Contents Page Figures and Tables Page Conventions Used in This Note About This NoteLCD Other Reference MaterialApda For More InformationPage Introduction to the PowerBook Duo 250 Computer PowerBook Duo 250 Computer Features Main expansion connector Page Hardware Modifications Active-Matrix Display Features MB Hard Disk Drive Inverter/Speaker BoardEnvironmental Specifications Housing Requirements1Hard disk drive housing Hardware Modifications Bracket for the hard disk drive Interface Requirements Hard Disk InterfaceGND Terminator Startup Not Applicable Random Operation Idle Standby Power RequirementsSoftware Modifications PowerBook Setup Panel PowerBook Duo 250 Control PanelsCustom and Easy Controls for Battery Conservation PowerBook Control PanelPower Conservation Index X, Y, Z
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