LSI Logic Confidential
Host Interface Registers
8-15
Copyright © 2001, 2002 by LSI Logic Corporation. All rights reserved.
Sdeb
Debug Interrupt
4
The host sets this read/writable bit to force the
processor’s RISC core to enter the DEBUG state. The
debug handler can poll this bit to determine the cause of
entering DEBUG state. If the processor is already in the
debug state, this bit is masked. The interrupt handler
should be used to clear this bit; this serves as the
acknowledge.
1 = Enter debug state.
0 = Normal operation.
Serr
CPU Error State or RISC Core Error Flag
3
The processor sets this bit when the RISC core enters
the ERROR state. CPUErr remains set until cleared by
software, an external reset, or when the ChipRst bit is
set.
1 = RISC core in error state.
0 = Normal operation.
Srst
CPU Reset
2
Setting this read/writable bit resets the SPARC core and
Video DSP. It does not reset other units, such as the
SDRAM controller, ME, video channel, video SPARC,
video DSP and Host interface--to allow debug access.
This bit is cleared by chip reset when no external host
interface is present (as determined by the Mode pins) to
allow the system SPARC processor to attempt booting
from PROM.
It is set by reset when the host interface is present. This
holds an DMN-8600 with an uninitialized SDRAM in reset
until the host completes downloading, when the host
clears CPU Reset to begin execution.
If the host sets CPU reset while processing is being
performed for debugging purposes, a full chip reset must
be performed with the Chip Reset bit before resuming
execution since pending RISC core transactions are left
in an undefined state.
Note:
It is not possible to predict when a write to CPURst and/or
ChipRST takes effect relative to other events in the DMN-
8600 processor due to the unpredictable latency of the
DMN-8600 internal bus arbitration.
Содержание DMN-8600
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