Types of smh files – Altera Advanced SEU Detection IP Core User Manual
Page 8
Interface
Signals
Type
Width
Description
External
Memory
Avalon-MM
Master
cache_data
Outpu
t
34
• Error cache data.
• This is the location information for an EMR
cache entry.
cache_valid
Outpu
t
1
Indicates when the cache_data contents are
valid.
cache_ready
Input
1
Indicates that the reader of the Avalon Stream
interface is ready.
cache_error
Outpu
t
1
This Avalon stream control signal indicates the
current transfer is in error and should be
ignored.
Cache Status
cache_fill_level
Outpu
t
4
Indicates how many entries are in the cache.
Related Information
SMH Lookup
The .smh file represents a hash of the CRAM bit settings on a design. Related groups of CRAM are
mapped to a signal bit in the sensitivity array. During an SEU event, a design can perform a lookup
against the
.smh
to determine if a bit is used. By using the information about the location of a bit, you can
reduce the effective soft error rate in a running system.
The following criteria determine the criticality of a CRAM location in your design:
• Routing—All bits that control a utilized routing line.
• Adaptive logic modules (ALMs)—If you configure an ALM, then the megafunction considers all
CRAM bits related to that ALM sensitive.
• Logic array block (LAB) control lines—If you use an ALM in a LAB, then the megafunction considers
all bits related to the control signals feeding that LAB sensitive.
• M20K memory blocks and digital signal processing (DSP) blocks—If you use a block, then the
megafunction considers all CRAM bits related to that block sensitive.
Related Information
Off-Chip Lookup Sensitivity Processing Operation Flow
Types of SMH Files
The .smh is an Intel-format Hexadecimal file. You can generate two revisions of
.smh
files:
• Revision 1—Generated for Stratix IV family devices. This revision does not support hierarchy tagging,
and does not contain tag size or region map information.
• Revision 2—Generated for Arria V, Cyclone V, and Stratix V, and later device families. The
generated .smh contains tag size and region map information.
8
SMH Lookup
ALTADVSEU
2015.05.04
Altera Corporation
Altera Advanced SEU Detection IP Core User Guide