3. Read the Interrupt Status (ISTAT) register.

 

 

4. If the SCSI Interrupt Pending bit is set, then read the

 

SCSI Interrupt Status Zero (SIST0) or SCSI Interrupt

 

Status One (SIST1) register to determine the cause of

 

the SCSI Interrupt and go back to Step 2.

 

 

5. If the SCSI Interrupt Pending bit is clear, and the DMA

 

Interrupt Pending bit is set, then write 0x00 value to

 

 

this register.

 

 

6. Read the DMA Status (DSTAT) register to verify the

 

 

aborted interrupt and to see if any other interrupting

 

conditions have occurred.

 

SRST

Software Reset

6

 

Setting this bit resets the LSI53C810A. All operating

 

 

registers are cleared to their respective default values

 

 

and all SCSI signals are deasserted. Setting this bit does

 

not assert the SCSI RST/ signal. This reset does not

 

 

clear the LSI53C700 family compatibility bit or any of the

 

PCI configuration registers. This bit is not self-clearing; it

 

must be cleared to clear the reset condition (a hardware

 

reset also clears this bit).

 

SIGP

Signal Process

5

 

SIGP is a R/W bit that is writable at any time, and polled

 

and reset using Chip Test Two (CTEST2). The SIGP bit

 

is used in various ways to pass a flag to or from a running

 

SCRIPTS instruction.

 

 

The only SCRIPTS instruction directly affected by the

 

 

SIGP bit is Wait for Selection/Reselection. Setting this bit

 

causes that instruction to jump to the alternate address

 

immediately. The instructions at the alternate jump

 

 

address should check the status of SIGP to determine

 

 

the cause of the jump. The SIGP bit may be used at any

 

time and is not restricted to the wait for selection/

 

 

reselection condition.

 

SEM

Semaphore

4

 

The SCRIPTS processor may set this bit using a

 

 

SCRIPTS register write instruction. An external processor

 

may also set it while the LSI53C810A is executing a

 

 

SCRIPTS operation. This bit enables the LSI53C810A to

 

notify an external processor of a predefined condition

 

 

while SCRIPTS are running. The external processor may

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LSI 53C810A technical manual Srst, Sigp, Sem