R

Reserved

1

IID

Illegal Instruction Detected

0

This status bit is set any time an illegal instruction is detected, whether the LSI53C810A is operating in single step mode or automatically executing SCSI SCRIPTS.

Any of the following conditions during instruction execution also set this bit:

The LSI53C810A is executing a Wait Disconnect instruction and the SCSI REQ line is asserted without a disconnect occurring.

A Move, Chained Move, or Memory Move command with a byte count of zero is fetched.

A Load/Store memory address maps back into chip register space.

Register: 0x0D (0x8D)

SCSI Status Zero (SSTAT0)

Read Only

7

6

5

4

3

2

1

 

0

ILF

ORF

OLF

AIP

LOA

WOA

RST/

 

SDP/

 

 

 

 

 

 

 

 

 

0

0

0

0

0

0

0

 

0

 

 

 

 

 

 

 

 

 

ILF

SIDL Full

 

 

 

 

 

7

 

This bit is set when the SCSI Input Data Latch (SIDL)

 

register contains data. Data is transferred from the SCSI

 

bus to the SCSI Input Data Latch register before being

 

sent to the DMA FIFO and then to the host bus. The

 

SCSI Input Data Latch (SIDL) register contains SCSI

 

data received asynchronously. Synchronous data

 

 

received does not flow through this register.

 

ORF

SODR Full

 

 

 

 

 

6

This bit is set when the SCSI Output Data Register (SODR, a hidden buffer register which is not accessible) contains data. The SODR register is used by the SCSI logic as a second storage register when sending data synchronously. It is not readable or writable by the user. It is possible to use this bit to determine how many bytes reside in the chip when an error occurs.

5-22

Operating Registers

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Image 96
LSI 53C810A technical manual Register 0x0D 0x8D, Iid, Ilf, Orf