Avago Technologies LSI53C1010 - Manual (Page 269)

Register Used for Debugging 12-3
12.2 Register Used for Debugging
The SCRIPTS registers and the SCSI registers contain information that
may be helpful in debugging the chip.
Table 12.1 shows the information
contained in the registers.
Table 12.1 Registers Useful for Debugging SCRIPTS Processor
Information Register Remarks
Information regarding the
most recent interrupt ISTAT Check this register first, since its contents may be
affected by reading or writing other registers.
Current SCRIPTS
instruction DCMD and DBC
(first 32-bits);
DNAD or DSPS
(second 32-bits) The DCMD and DBC always contain the opcode
of the most recently executed SCRIPTS
instruction. Use the cross reference file created
from the SCRIPTS source by NASM to interpret
the contents. The DSPS or DNAD contains the
second 32-bit field of the SCRIPTS instruction
fetched.
Next SCRIPTS
Instruction address DSP Contains the address of the next instruction to be
fetched. This is analogous to the program counter
of a microprocessor. Instruction addresses are on
8-byte boundaries (except Memory Move, which is
on a 12-byte boundary) and so the value in the
DSP should be eight past the address of the
current instruction.
SCSI Bus Control Lines SBCL Contains the current state of the SCSI control
lines.
SCSI Bus Data Lines SBDL Contains the current status of the SCSI data lines.
Last SCSI Phase
serviced SOCL Contains the phase to match (initiator) or the
phase driven (target) from the last SCRIPTS
instruction executed.
Last SCSI data byte sent SODL Contains the last byte transferred to the SCSI bus.
Last SCSI data byte
received SIDL Contains the last byte transferred in from the SCSI
bus.
First byte received from
Block Move instruction
executed SFBR Contains the first byte of a block move transferred
in from the SCSI bus. It also contains SCSI
identities after a reselection, if using the
LSI53C700 compatibility mode and if the IDs are
in the 0–7 range.
SCSI ID SCID Contains the chip’s SCSI ID.