3.3.6

Interrupt Signal

 

 

 

 

 

 

Table 3.7 describes the Interrupt signal.

Table 3.7

Interrupt Signal

 

 

 

 

 

 

 

 

 

Name

PQFP

BGA

 

Type

 

Strength

Description

 

 

 

 

 

 

 

 

 

IRQ/

52

 

M5

 

O

 

8 mA PCI

Interrupt Request. This signal, when asserted LOW,

 

 

 

 

 

 

 

 

indicates that an interrupting condition has occurred and

 

 

 

 

 

 

 

 

that service is required from the host CPU. The output

 

 

 

 

 

 

 

 

drive of this pin is open drain.

 

 

 

 

 

 

 

 

 

1. See Register 0x4D, SCSI Test One (STEST1) in Chapter 4 for additional information on this signal.

3.4 SCSI Bus Interface Signals

The SCSI Bus Interface signals section contains tables describing the signals for the following signal groups: SCSI Bus Interface Signals, SCSI Signals, and SCSI Control Signals.

3.4.1 SCSI Bus Interface Signal

Table 3.8 describes the SCSI Bus Interface signal.

Table 3.8 SCSI Bus Interface Signal

Name

PQFP

BGA

Type

Strength

Description

 

 

 

 

 

 

SCLK

56

M6

I

N/A

SCSI Clock is used to derive all SCSI-related timings. The

 

 

 

 

 

speed of this clock is determined by the application’s

 

 

 

 

 

requirements. In some applications, SCLK may be sourced

 

 

 

 

 

internally from the PCI bus clock (CLK). If SCLK is

 

 

 

 

 

internally sourced, then the SCLK pin should be tied low.

 

 

 

 

 

 

3-8

Signal Descriptions

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LSI 53C875A technical manual Scsi Bus Interface Signals, Interrupt Signal