beautypg.com

Avago Technologies LSI53C825AE User Manual

Page 219

background image

Transfer Control Instructions

5-35

IF

Interrupt-on-the-Fly

20

When this bit is set, the interrupt instruction does not halt
the SCRIPTS processor. Once the interrupt occurs, the
Interrupt-on-the-Fly bit (

Interrupt Status (ISTAT)

, bit 2) is

asserted.

JMP

Jump If True/False

19

This bit determines whether the LSI53C825A branches
when a comparison is true or when a comparison is false.
This bit applies to phase compares, data compares, and
carry tests. If both the Phase Compare and Data
Compare bits are set, then both compares must be true
to branch on a true condition. Both compares must be
false to branch on a false condition.

CD

Compare Data

18

When this bit is set, the first byte received from the SCSI
data bus (contained in the

SCSI First Byte Received

(SFBR)

register) is compared with the Data to be

Compared Field in the Transfer Control instruction. The
Wait for Valid Phase bit controls when this compare
occurs. The Jump if True/False bit determines the
condition (true or false) to branch on.

CP

Compare Phase

17

When the LSI53C825A is in Initiator mode, this bit
controls phase compare operations. When this bit is set,
the SCSI phase signals (latched by SREQ/) are
compared to the Phase Field in the Transfer Control
instruction. If they match, the comparison is true. The
Wait for Valid Phase bit controls when the compare
occurs. When the LSI53C825A is operating in Target
mode and this bit is set, it tests for an active SCSI SATN/
signal.

Bit 19

Result of
Compare

Action

0

False

Jump Taken

0

True

No Jump

1

False

No Jump

1

True

Jump Taken