Scsi Error Status Register - Motorola MVME162FX Programmer's Reference Manual

SCSI Error Status Register

ADR/SIZ
31
BIT
NAME
OPER R/W
RESET 0
SCLR
LTO,EXT,
PRTY
$FFF4202C (8 bits)
30 29 28
R R R
0 0 0
Writing a 1 to this bit clears bits LTO, EXT, and
PRTY. Reading this bit always yields 0.
These bits indicate the status of the last local bus
error condition encountered by the SCSI processor
while performing DMA accesses to the local bus. A
local bus error condition is flagged by the assertion
of TEA*. When the SCSI processor receives TEA*, if
the source of the error is local time-out, then LTO is
set and EXT and PRTY are cleared. If the
source of the TEA* is due to an error in going to the
VMEbus, then EXT is set and the other two status
bits are cleared. If the source of the error is DRAM
parity check error, then PRTY is set and the other
two status bits are cleared. If the source of the error
is none of the above conditions, then all three bits are
cleared. Writing a 1 to bit 24 (SCLR) also clears all
three bits.
Programming Model
27 26 25
PRTY EXT LTO
R R R
0 PL 0 PL 0 PL
3
24
SCLR
C
0 PL
3-35