LSI 53C875A User Manual
Page 132
4-40
Registers
MDPE
Master Data Parity Error
6
This bit is set when the LSI53C875A as a master detects
a data parity error, or a target device signals a parity error
during a data phase. This bit is completely disabled by
the Master Parity Error Enable bit (bit 3 of
).
BF
Bus Fault
5
This bit is set when a PCI bus fault condition is detected.
A PCI bus fault can only occur when the LSI53C875A is
bus master, and is defined as a cycle that ends with a
Bad Address or Target Abort Condition.
ABRT
Aborted
4
This bit is set when an abort condition occurs. An abort
condition occurs when a software abort command is
issued by setting bit 7 of the
register.
SSI
Single Step Interrupt
3
If the Single Step Mode bit in the
register is set, this bit is set and an interrupt is generated
after successful execution of each SCRIPTS instruction.
SIR
SCRIPTS Interrupt Instruction Received
2
This status bit is set whenever an Interrupt instruction is
evaluated as true.
R
Reserved
1
IID
Illegal Instruction Detected
0
This status bit is set any time an illegal or reserved
instruction opcode is detected, whether the LSI53C875A
is operating in single step mode or automatically
executing SCSI SCRIPTS.
Any of the following conditions during instruction
execution also set this bit:
•
The LSI53C875A is executing a Wait Disconnect
instruction and the SCSI REQ line is asserted without
a disconnect occurring.
•
A Block Move instruction is executed with 0x000000
loaded into the
register,
indicating there are zero bytes to move.